Python运算符、基本数据类型

一、运算符

1、算数运算：

2、比较运算：

3、赋值运算：

4、逻辑运算：

5、成员运算：

二、基本数据类型

数据类型转换图：

 

1、数字
#整型int
　　定义：age=10 #本质age=int(10)
　　注意：在整数两边加上引号就是字符串类型。

#浮点型float
　　作用：薪资，身高，体重，体质参数等浮点数相关
定义：salary=3000.3 #本质salary=float(3000.3) #二进制，十进制，八进制，十六进制 

int（整型）

　　在32位机器上，整数的位数为32位，取值范围为-2**31～2**31-1，即-2147483648～2147483647
　　在64位系统上，整数的位数为64位，取值范围为-2**63～2**63-1，即-9223372036854775808～9223372036854775807 
  1 class int(object):
  2     """
  3     int(x=0) -> int or long
  4     int(x, base=10) -> int or long
  5     
  6     Convert a number or string to an integer, or return 0 if no arguments
  7     are given.  If x is floating point, the conversion truncates towards zero.
  8     If x is outside the integer range, the function returns a long instead.
  9     
 10     If x is not a number or if base is given, then x must be a string or
 11     Unicode object representing an integer literal in the given base.  The
 12     literal can be preceded by '+' or '-' and be surrounded by whitespace.
 13     The base defaults to 10.  Valid bases are 0 and 2-36.  Base 0 means to
 14     interpret the base from the string as an integer literal.
 15     >>> int('0b100', base=0)
 16     4
 17     """
 18     def bit_length(self): 
 19         """ 返回表示该数字的时占用的最少位数 """
 20         """
 21         int.bit_length() -> int
 22         
 23         Number of bits necessary to represent self in binary.
 24         >>> bin(37)
 25         '0b100101'
 26         >>> (37).bit_length()
 27         6
 28         """
 29         return 0
 30 
 31     def conjugate(self, *args, **kwargs): # real signature unknown
 32         """ 返回该复数的共轭复数 """
 33         """ Returns self, the complex conjugate of any int. """
 34         pass
 35 
 36     def __abs__(self):
 37         """ 返回绝对值 """
 38         """ x.__abs__() <==> abs(x) """
 39         pass
 40 
 41     def __add__(self, y):
 42         """ x.__add__(y) <==> x+y """
 43         pass
 44 
 45     def __and__(self, y):
 46         """ x.__and__(y) <==> x&y """
 47         pass
 48 
 49     def __cmp__(self, y): 
 50         """ 比较两个数大小 """
 51         """ x.__cmp__(y) <==> cmp(x,y) """
 52         pass
 53 
 54     def __coerce__(self, y):
 55         """ 强制生成一个元组 """ 
 56         """ x.__coerce__(y) <==> coerce(x, y) """
 57         pass
 58 
 59     def __divmod__(self, y): 
 60         """ 相除，得到商和余数组成的元组 """ 
 61         """ x.__divmod__(y) <==> divmod(x, y) """
 62         pass
 63 
 64     def __div__(self, y): 
 65         """ x.__div__(y) <==> x/y """
 66         pass
 67 
 68     def __float__(self): 
 69         """ 转换为浮点类型 """ 
 70         """ x.__float__() <==> float(x) """
 71         pass
 72 
 73     def __floordiv__(self, y): 
 74         """ x.__floordiv__(y) <==> x//y """
 75         pass
 76 
 77     def __format__(self, *args, **kwargs): # real signature unknown
 78         pass
 79 
 80     def __getattribute__(self, name): 
 81         """ x.__getattribute__('name') <==> x.name """
 82         pass
 83 
 84     def __getnewargs__(self, *args, **kwargs): # real signature unknown
 85         """ 内部调用 __new__方法或创建对象时传入参数使用 """ 
 86         pass
 87 
 88     def __hash__(self): 
 89         """如果对象object为哈希表类型，返回对象object的哈希值。哈希值为整数。在字典查找中，哈希值用于快速比较字典的键。两个数值如果相等，则哈希值也相等。"""
 90         """ x.__hash__() <==> hash(x) """
 91         pass
 92 
 93     def __hex__(self): 
 94         """ 返回当前数的 十六进制 表示 """ 
 95         """ x.__hex__() <==> hex(x) """
 96         pass
 97 
 98     def __index__(self): 
 99         """ 用于切片，数字无意义 """
100         """ x[y:z] <==> x[y.__index__():z.__index__()] """
101         pass
102 
103     def __init__(self, x, base=10): # known special case of int.__init__
104         """ 构造方法，执行 x = 123 或 x = int(10) 时，自动调用，暂时忽略 """ 
105         """
106         int(x=0) -> int or long
107         int(x, base=10) -> int or long
108         
109         Convert a number or string to an integer, or return 0 if no arguments
110         are given.  If x is floating point, the conversion truncates towards zero.
111         If x is outside the integer range, the function returns a long instead.
112         
113         If x is not a number or if base is given, then x must be a string or
114         Unicode object representing an integer literal in the given base.  The
115         literal can be preceded by '+' or '-' and be surrounded by whitespace.
116         The base defaults to 10.  Valid bases are 0 and 2-36.  Base 0 means to
117         interpret the base from the string as an integer literal.
118         >>> int('0b100', base=0)
119         4
120         # (copied from class doc)
121         """
122         pass
123 
124     def __int__(self): 
125         """ 转换为整数 """ 
126         """ x.__int__() <==> int(x) """
127         pass
128 
129     def __invert__(self): 
130         """ x.__invert__() <==> ~x """
131         pass
132 
133     def __long__(self): 
134         """ 转换为长整数 """ 
135         """ x.__long__() <==> long(x) """
136         pass
137 
138     def __lshift__(self, y): 
139         """ x.__lshift__(y) <==> x<<y """
140         pass
141 
142     def __mod__(self, y): 
143         """ x.__mod__(y) <==> x%y """
144         pass
145 
146     def __mul__(self, y): 
147         """ x.__mul__(y) <==> x*y """
148         pass
149 
150     def __neg__(self): 
151         """ x.__neg__() <==> -x """
152         pass
153 
154     @staticmethod # known case of __new__
155     def __new__(S, *more): 
156         """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
157         pass
158 
159     def __nonzero__(self): 
160         """ x.__nonzero__() <==> x != 0 """
161         pass
162 
163     def __oct__(self): 
164         """ 返回改值的 八进制 表示 """ 
165         """ x.__oct__() <==> oct(x) """
166         pass
167 
168     def __or__(self, y): 
169         """ x.__or__(y) <==> x|y """
170         pass
171 
172     def __pos__(self): 
173         """ x.__pos__() <==> +x """
174         pass
175 
176     def __pow__(self, y, z=None): 
177         """ 幂，次方 """ 
178         """ x.__pow__(y[, z]) <==> pow(x, y[, z]) """
179         pass
180 
181     def __radd__(self, y): 
182         """ x.__radd__(y) <==> y+x """
183         pass
184 
185     def __rand__(self, y): 
186         """ x.__rand__(y) <==> y&x """
187         pass
188 
189     def __rdivmod__(self, y): 
190         """ x.__rdivmod__(y) <==> divmod(y, x) """
191         pass
192 
193     def __rdiv__(self, y): 
194         """ x.__rdiv__(y) <==> y/x """
195         pass
196 
197     def __repr__(self): 
198         """转化为解释器可读取的形式 """
199         """ x.__repr__() <==> repr(x) """
200         pass
201 
202     def __str__(self): 
203         """转换为人阅读的形式，如果没有适于人阅读的解释形式的话，则返回解释器课阅读的形式"""
204         """ x.__str__() <==> str(x) """
205         pass
206 
207     def __rfloordiv__(self, y): 
208         """ x.__rfloordiv__(y) <==> y//x """
209         pass
210 
211     def __rlshift__(self, y): 
212         """ x.__rlshift__(y) <==> y<<x """
213         pass
214 
215     def __rmod__(self, y): 
216         """ x.__rmod__(y) <==> y%x """
217         pass
218 
219     def __rmul__(self, y): 
220         """ x.__rmul__(y) <==> y*x """
221         pass
222 
223     def __ror__(self, y): 
224         """ x.__ror__(y) <==> y|x """
225         pass
226 
227     def __rpow__(self, x, z=None): 
228         """ y.__rpow__(x[, z]) <==> pow(x, y[, z]) """
229         pass
230 
231     def __rrshift__(self, y): 
232         """ x.__rrshift__(y) <==> y>>x """
233         pass
234 
235     def __rshift__(self, y): 
236         """ x.__rshift__(y) <==> x>>y """
237         pass
238 
239     def __rsub__(self, y): 
240         """ x.__rsub__(y) <==> y-x """
241         pass
242 
243     def __rtruediv__(self, y): 
244         """ x.__rtruediv__(y) <==> y/x """
245         pass
246 
247     def __rxor__(self, y): 
248         """ x.__rxor__(y) <==> y^x """
249         pass
250 
251     def __sub__(self, y): 
252         """ x.__sub__(y) <==> x-y """
253         pass
254 
255     def __truediv__(self, y): 
256         """ x.__truediv__(y) <==> x/y """
257         pass
258 
259     def __trunc__(self, *args, **kwargs): 
260         """ 返回数值被截取为整形的值，在整形中无意义 """
261         pass
262 
263     def __xor__(self, y): 
264         """ x.__xor__(y) <==> x^y """
265         pass
266 
267     denominator = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
268     """ 分母 = 1 """
269     """the denominator of a rational number in lowest terms"""
270 
271     imag = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
272     """ 虚数，无意义 """
273     """the imaginary part of a complex number"""
274 
275     numerator = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
276     """ 分子 = 数字大小 """
277     """the numerator of a rational number in lowest terms"""
278 
279     real = property(lambda self: object(), lambda self, v: None, lambda self: None)  # default
280     """ 实属，无意义 """
281     """the real part of a complex number"""
int的类源码

 

2、布尔值
　　真或假
　　1 或 0
3、字符串
"hello world"　　#定义：在单引号\双引号\三引号内，由一串字符组成
　　字符串常用功能：
    • #1、按索引取值(正向取+反向取) ：只能取
#2、切片(顾头不顾尾，步长)　　split切割（会损耗字符串）如果没带参数则默认是按不可见切割如空格或  \t  或\n    splitlines按行切割，保存到列表中
#3、长度len
#4、成员运算in和not in
#5、移除空白strip
#6、切分split
#7、循环
  • 需要掌握的操作:　 
    • #1、strip,lstrip,rstrip删除左右或两端空格
#2、lower都变小写upper都变大写
#3、startswith,endswith
#4、format的三种玩法
#5、split,rsplit
#6、join　　#join以字符串名（保存的字符）为间隔把列表内的字符连接成字符串。
#7、replace
#8、isdigit

    • isalpha是不是纯字母

    • isdigit是不是纯数字

    • isalnum是不是字母和数字组合

    • isspase是不是纯空格 

       1 #strip
 2 name='*egon**'
 3 print(name.strip('*'))
 4 print(name.lstrip('*'))
 5 print(name.rstrip('*'))
 6 
 7 #lower,upper
 8 name='egon'
 9 print(name.lower())
10 print(name.upper())
11 
12 #startswith,endswith
13 name='alex_SB'
14 print(name.endswith('SB'))
15 print(name.startswith('alex'))
16 
17 #format的三种玩法
18 res='{} {} {}'.format('egon',18,'male')
19 res='{1} {0} {1}'.format('egon',18,'male')
20 res='{name} {age} {sex}'.format(sex='male',name='egon',age=18)
21 
22 #split
23 name='root:x:0:0::/root:/bin/bash'
24 print(name.split(':')) #默认分隔符为空格
25 name='C:/a/b/c/d.txt' #只想拿到顶级目录
26 print(name.split('/',1))
27 
28 name='a|b|c'
29 print(name.rsplit('|',1)) #从右开始切分
30 
31 #join
32 tag=' '
33 print(tag.join(['egon','say','hello','world'])) #可迭代对象必须都是字符串
34 
35 #replace
36 name='alex say :i have one tesla,my name is alex'
37 print(name.replace('alex','SB',1))
38 
39 #isdigit：可以判断bytes和unicode类型,是最常用的用于于判断字符是否为"数字"的方法
40 age=input('>>: ')
41 print(age.isdigit())
      例子
  •   1 class str(basestring):
  2     """
  3     str(object='') -> string
  4     
  5     Return a nice string representation of the object.
  6     If the argument is a string, the return value is the same object.
  7     """
  8     def capitalize(self):  
  9         """ 首字母变大写 """
 10         """
 11         S.capitalize() -> string
 12         
 13         Return a copy of the string S with only its first character
 14         capitalized.
 15         """
 16         return ""
 17 
 18     def center(self, width, fillchar=None):  
 19         """ 内容居中，width：总长度；fillchar：空白处填充内容，默认无 """
 20         """
 21         S.center(width[, fillchar]) -> string
 22         
 23         Return S centered in a string of length width. Padding is
 24         done using the specified fill character (default is a space)
 25         """
 26         return ""
 27 
 28     def count(self, sub, start=None, end=None):  
 29         """ 子序列个数 """
 30         """
 31         S.count(sub[, start[, end]]) -> int
 32         
 33         Return the number of non-overlapping occurrences of substring sub in
 34         string S[start:end].  Optional arguments start and end are interpreted
 35         as in slice notation.
 36         """
 37         return 0
 38 
 39     def decode(self, encoding=None, errors=None):  
 40         """ 解码 """
 41         """
 42         S.decode([encoding[,errors]]) -> object
 43         
 44         Decodes S using the codec registered for encoding. encoding defaults
 45         to the default encoding. errors may be given to set a different error
 46         handling scheme. Default is 'strict' meaning that encoding errors raise
 47         a UnicodeDecodeError. Other possible values are 'ignore' and 'replace'
 48         as well as any other name registered with codecs.register_error that is
 49         able to handle UnicodeDecodeErrors.
 50         """
 51         return object()
 52 
 53     def encode(self, encoding=None, errors=None):  
 54         """ 编码，针对unicode """
 55         """
 56         S.encode([encoding[,errors]]) -> object
 57         
 58         Encodes S using the codec registered for encoding. encoding defaults
 59         to the default encoding. errors may be given to set a different error
 60         handling scheme. Default is 'strict' meaning that encoding errors raise
 61         a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
 62         'xmlcharrefreplace' as well as any other name registered with
 63         codecs.register_error that is able to handle UnicodeEncodeErrors.
 64         """
 65         return object()
 66 
 67     def endswith(self, suffix, start=None, end=None):  
 68         """ 是否以 xxx 结束 """
 69         """
 70         S.endswith(suffix[, start[, end]]) -> bool
 71         
 72         Return True if S ends with the specified suffix, False otherwise.
 73         With optional start, test S beginning at that position.
 74         With optional end, stop comparing S at that position.
 75         suffix can also be a tuple of strings to try.
 76         """
 77         return False
 78 
 79     def expandtabs(self, tabsize=None):  
 80         """ 将tab转换成空格，默认一个tab转换成8个空格 """
 81         """
 82         S.expandtabs([tabsize]) -> string
 83         
 84         Return a copy of S where all tab characters are expanded using spaces.
 85         If tabsize is not given, a tab size of 8 characters is assumed.
 86         """
 87         return ""
 88 
 89     def find(self, sub, start=None, end=None):  
 90         """ 寻找子序列位置，如果没找到，返回 -1 """
 91         """
 92         S.find(sub [,start [,end]]) -> int
 93         
 94         Return the lowest index in S where substring sub is found,
 95         such that sub is contained within S[start:end].  Optional
 96         arguments start and end are interpreted as in slice notation.
 97         
 98         Return -1 on failure.
 99         """
100         return 0
101 
102     def format(*args, **kwargs): # known special case of str.format
103         """ 字符串格式化，动态参数，将函数式编程时细说 """
104         """
105         S.format(*args, **kwargs) -> string
106         
107         Return a formatted version of S, using substitutions from args and kwargs.
108         The substitutions are identified by braces ('{' and '}').
109         """
110         pass
111 
112     def index(self, sub, start=None, end=None):  
113         """ 子序列位置，如果没找到，报错 """
114         S.index(sub [,start [,end]]) -> int
115         
116         Like S.find() but raise ValueError when the substring is not found.
117         """
118         return 0
119 
120     def isalnum(self):  
121         """ 是否是字母和数字 """
122         """
123         S.isalnum() -> bool
124         
125         Return True if all characters in S are alphanumeric
126         and there is at least one character in S, False otherwise.
127         """
128         return False
129 
130     def isalpha(self):  
131         """ 是否是字母 """
132         """
133         S.isalpha() -> bool
134         
135         Return True if all characters in S are alphabetic
136         and there is at least one character in S, False otherwise.
137         """
138         return False
139 
140     def isdigit(self):  
141         """ 是否是数字 """
142         """
143         S.isdigit() -> bool
144         
145         Return True if all characters in S are digits
146         and there is at least one character in S, False otherwise.
147         """
148         return False
149 
150     def islower(self):  
151         """ 是否小写 """
152         """
153         S.islower() -> bool
154         
155         Return True if all cased characters in S are lowercase and there is
156         at least one cased character in S, False otherwise.
157         """
158         return False
159 
160     def isspace(self):  
161         """
162         S.isspace() -> bool
163         
164         Return True if all characters in S are whitespace
165         and there is at least one character in S, False otherwise.
166         """
167         return False
168 
169     def istitle(self):  
170         """
171         S.istitle() -> bool
172         
173         Return True if S is a titlecased string and there is at least one
174         character in S, i.e. uppercase characters may only follow uncased
175         characters and lowercase characters only cased ones. Return False
176         otherwise.
177         """
178         return False
179 
180     def isupper(self):  
181         """
182         S.isupper() -> bool
183         
184         Return True if all cased characters in S are uppercase and there is
185         at least one cased character in S, False otherwise.
186         """
187         return False
188 
189     def join(self, iterable):  
190         """ 连接 """
191         """
192         S.join(iterable) -> string
193         
194         Return a string which is the concatenation of the strings in the
195         iterable.  The separator between elements is S.
196         """
197         return ""
198 
199     def ljust(self, width, fillchar=None):  
200         """ 内容左对齐，右侧填充 """
201         """
202         S.ljust(width[, fillchar]) -> string
203         
204         Return S left-justified in a string of length width. Padding is
205         done using the specified fill character (default is a space).
206         """
207         return ""
208 
209     def lower(self):  
210         """ 变小写 """
211         """
212         S.lower() -> string
213         
214         Return a copy of the string S converted to lowercase.
215         """
216         return ""
217 
218     def lstrip(self, chars=None):  
219         """ 移除左侧空白 """
220         """
221         S.lstrip([chars]) -> string or unicode
222         
223         Return a copy of the string S with leading whitespace removed.
224         If chars is given and not None, remove characters in chars instead.
225         If chars is unicode, S will be converted to unicode before stripping
226         """
227         return ""
228 
229     def partition(self, sep):  
230         """ 分割，前，中，后三部分 """
231         """
232         S.partition(sep) -> (head, sep, tail)
233         
234         Search for the separator sep in S, and return the part before it,
235         the separator itself, and the part after it.  If the separator is not
236         found, return S and two empty strings.
237         """
238         pass
239 
240     def replace(self, old, new, count=None):  
241         """ 替换 """
242         """
243         S.replace(old, new[, count]) -> string
244         
245         Return a copy of string S with all occurrences of substring
246         old replaced by new.  If the optional argument count is
247         given, only the first count occurrences are replaced.
248         """
249         return ""
250 
251     def rfind(self, sub, start=None, end=None):  
252         """
253         S.rfind(sub [,start [,end]]) -> int
254         
255         Return the highest index in S where substring sub is found,
256         such that sub is contained within S[start:end].  Optional
257         arguments start and end are interpreted as in slice notation.
258         
259         Return -1 on failure.
260         """
261         return 0
262 
263     def rindex(self, sub, start=None, end=None):  
264         """
265         S.rindex(sub [,start [,end]]) -> int
266         
267         Like S.rfind() but raise ValueError when the substring is not found.
268         """
269         return 0
270 
271     def rjust(self, width, fillchar=None):  
272         """
273         S.rjust(width[, fillchar]) -> string
274         
275         Return S right-justified in a string of length width. Padding is
276         done using the specified fill character (default is a space)
277         """
278         return ""
279 
280     def rpartition(self, sep):  
281         """
282         S.rpartition(sep) -> (head, sep, tail)
283         
284         Search for the separator sep in S, starting at the end of S, and return
285         the part before it, the separator itself, and the part after it.  If the
286         separator is not found, return two empty strings and S.
287         """
288         pass
289 
290     def rsplit(self, sep=None, maxsplit=None):  
291         """
292         S.rsplit([sep [,maxsplit]]) -> list of strings
293         
294         Return a list of the words in the string S, using sep as the
295         delimiter string, starting at the end of the string and working
296         to the front.  If maxsplit is given, at most maxsplit splits are
297         done. If sep is not specified or is None, any whitespace string
298         is a separator.
299         """
300         return []
301 
302     def rstrip(self, chars=None):  
303         """
304         S.rstrip([chars]) -> string or unicode
305         
306         Return a copy of the string S with trailing whitespace removed.
307         If chars is given and not None, remove characters in chars instead.
308         If chars is unicode, S will be converted to unicode before stripping
309         """
310         return ""
311 
312     def split(self, sep=None, maxsplit=None):  
313         """ 分割， maxsplit最多分割几次 """
314         """
315         S.split([sep [,maxsplit]]) -> list of strings
316         
317         Return a list of the words in the string S, using sep as the
318         delimiter string.  If maxsplit is given, at most maxsplit
319         splits are done. If sep is not specified or is None, any
320         whitespace string is a separator and empty strings are removed
321         from the result.
322         """
323         return []
324 
325     def splitlines(self, keepends=False):  
326         """ 根据换行分割 """
327         """
328         S.splitlines(keepends=False) -> list of strings
329         
330         Return a list of the lines in S, breaking at line boundaries.
331         Line breaks are not included in the resulting list unless keepends
332         is given and true.
333         """
334         return []
335 
336     def startswith(self, prefix, start=None, end=None):  
337         """ 是否起始 """
338         """
339         S.startswith(prefix[, start[, end]]) -> bool
340         
341         Return True if S starts with the specified prefix, False otherwise.
342         With optional start, test S beginning at that position.
343         With optional end, stop comparing S at that position.
344         prefix can also be a tuple of strings to try.
345         """
346         return False
347 
348     def strip(self, chars=None):  
349         """ 移除两段空白 """
350         """
351         S.strip([chars]) -> string or unicode
352         
353         Return a copy of the string S with leading and trailing
354         whitespace removed.
355         If chars is given and not None, remove characters in chars instead.
356         If chars is unicode, S will be converted to unicode before stripping
357         """
358         return ""
359 
360     def swapcase(self):  
361         """ 大写变小写，小写变大写 """
362         """
363         S.swapcase() -> string
364         
365         Return a copy of the string S with uppercase characters
366         converted to lowercase and vice versa.
367         """
368         return ""
369 
370     def title(self):  
371         """
372         S.title() -> string
373         
374         Return a titlecased version of S, i.e. words start with uppercase
375         characters, all remaining cased characters have lowercase.
376         """
377         return ""
378 
379     def translate(self, table, deletechars=None):  
380         """
381         转换，需要先做一个对应表，最后一个表示删除字符集合
382         intab = "aeiou"
383         outtab = "12345"
384         trantab = maketrans(intab, outtab)
385         str = "this is string example....wow!!!"
386         print str.translate(trantab, 'xm')
387         """
388 
389         """
390         S.translate(table [,deletechars]) -> string
391         
392         Return a copy of the string S, where all characters occurring
393         in the optional argument deletechars are removed, and the
394         remaining characters have been mapped through the given
395         translation table, which must be a string of length 256 or None.
396         If the table argument is None, no translation is applied and
397         the operation simply removes the characters in deletechars.
398         """
399         return ""
400 
401     def upper(self):  
402         """
403         S.upper() -> string
404         
405         Return a copy of the string S converted to uppercase.
406         """
407         return ""
408 
409     def zfill(self, width):  
410         """方法返回指定长度的字符串，原字符串右对齐，前面填充0。"""
411         """
412         S.zfill(width) -> string
413         
414         Pad a numeric string S with zeros on the left, to fill a field
415         of the specified width.  The string S is never truncated.
416         """
417         return ""
418 
419     def _formatter_field_name_split(self, *args, **kwargs): # real signature unknown
420         pass
421 
422     def _formatter_parser(self, *args, **kwargs): # real signature unknown
423         pass
424 
425     def __add__(self, y):  
426         """ x.__add__(y) <==> x+y """
427         pass
428 
429     def __contains__(self, y):  
430         """ x.__contains__(y) <==> y in x """
431         pass
432 
433     def __eq__(self, y):  
434         """ x.__eq__(y) <==> x==y """
435         pass
436 
437     def __format__(self, format_spec):  
438         """
439         S.__format__(format_spec) -> string
440         
441         Return a formatted version of S as described by format_spec.
442         """
443         return ""
444 
445     def __getattribute__(self, name):  
446         """ x.__getattribute__('name') <==> x.name """
447         pass
448 
449     def __getitem__(self, y):  
450         """ x.__getitem__(y) <==> x[y] """
451         pass
452 
453     def __getnewargs__(self, *args, **kwargs): # real signature unknown
454         pass
455 
456     def __getslice__(self, i, j):  
457         """
458         x.__getslice__(i, j) <==> x[i:j]
459                    
460                    Use of negative indices is not supported.
461         """
462         pass
463 
464     def __ge__(self, y):  
465         """ x.__ge__(y) <==> x>=y """
466         pass
467 
468     def __gt__(self, y):  
469         """ x.__gt__(y) <==> x>y """
470         pass
471 
472     def __hash__(self):  
473         """ x.__hash__() <==> hash(x) """
474         pass
475 
476     def __init__(self, string=''): # known special case of str.__init__
477         """
478         str(object='') -> string
479         
480         Return a nice string representation of the object.
481         If the argument is a string, the return value is the same object.
482         # (copied from class doc)
483         """
484         pass
485 
486     def __len__(self):  
487         """ x.__len__() <==> len(x) """
488         pass
489 
490     def __le__(self, y):  
491         """ x.__le__(y) <==> x<=y """
492         pass
493 
494     def __lt__(self, y):  
495         """ x.__lt__(y) <==> x<y """
496         pass
497 
498     def __mod__(self, y):  
499         """ x.__mod__(y) <==> x%y """
500         pass
501 
502     def __mul__(self, n):  
503         """ x.__mul__(n) <==> x*n """
504         pass
505 
506     @staticmethod # known case of __new__
507     def __new__(S, *more):  
508         """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
509         pass
510 
511     def __ne__(self, y):  
512         """ x.__ne__(y) <==> x!=y """
513         pass
514 
515     def __repr__(self):  
516         """ x.__repr__() <==> repr(x) """
517         pass
518 
519     def __rmod__(self, y):  
520         """ x.__rmod__(y) <==> y%x """
521         pass
522 
523     def __rmul__(self, n):  
524         """ x.__rmul__(n) <==> n*x """
525         pass
526 
527     def __sizeof__(self):  
528         """ S.__sizeof__() -> size of S in memory, in bytes """
529         pass
530 
531     def __str__(self):  
532         """ x.__str__() <==> str(x) """
533         pass
    str类源码 
     1 #find,rfind,index,rindex,count
 2 name='egon say hello'
 3 print(name.find('o',1,3)) #顾头不顾尾,找不到则返回-1不会报错,找到了则显示索引
 4 # print(name.index('e',2,4)) #同上,但是找不到会报错
 5 print(name.count('e',1,3)) #顾头不顾尾,如果不指定范围则查找所有
 6 
 7 #center,ljust,rjust,zfill
 8 name='egon'
 9 print(name.center(30,'-'))
10 print(name.ljust(30,'*'))
11 print(name.rjust(30,'*'))
12 print(name.zfill(50)) #用0填充
13 
14 #expandtabs
15 name='egon\thello'
16 print(name)
17 print(name.expandtabs(1))
18 
19 #captalize,swapcase,title
20 print(name.capitalize()) #首字母大写
21 print(name.swapcase()) #大小写翻转
22 msg='egon say hi'
23 print(msg.title()) #每个单词的首字母大写
24 
25 #is数字系列
26 #在python3中
27 num1=b'4' #bytes
28 num2=u'4' #unicode,python3中无需加u就是unicode
29 num3='四' #中文数字
30 num4='Ⅳ' #罗马数字
31 
32 #isdigt:bytes,unicode
33 print(num1.isdigit()) #True
34 print(num2.isdigit()) #True
35 print(num3.isdigit()) #False
36 print(num4.isdigit()) #False
37 
38 #isdecimal:uncicode
39 #bytes类型无isdecimal方法
40 print(num2.isdecimal()) #True
41 print(num3.isdecimal()) #False
42 print(num4.isdecimal()) #False
43 
44 #isnumberic:unicode,中文数字,罗马数字
45 #bytes类型无isnumberic方法
46 print(num2.isnumeric()) #True
47 print(num3.isnumeric()) #True
48 print(num4.isnumeric()) #True
49 
50 #三者不能判断浮点数
51 num5='4.3'
52 print(num5.isdigit())
53 print(num5.isdecimal())
54 print(num5.isnumeric())
55 '''
56 总结:
57     最常用的是isdigit,可以判断bytes和unicode类型,这也是最常见的数字应用场景
58     如果要判断中文数字或罗马数字,则需要用到isnumeric
59 '''
60 
61 #is其他
62 print('===>')
63 name='egon123'
64 print(name.isalnum()) #字符串由字母或数字组成
65 print(name.isalpha()) #字符串只由字母组成
66 
67 print(name.isidentifier())
68 print(name.islower())
69 print(name.isupper())
70 print(name.isspace())
71 print(name.istitle())
    其他操作（了解） 
     1 # 写代码,有如下变量,请按照要求实现每个功能 （共6分，每小题各0.5分）
 2 name = " aleX"
 3 # 1)    移除 name 变量对应的值两边的空格,并输出处理结果
 4 # 2)    判断 name 变量对应的值是否以 "al" 开头,并输出结果

 5 # 3)    判断 name 变量对应的值是否以 "X" 结尾,并输出结果

 6 # 4)    将 name 变量对应的值中的 “l” 替换为 “p”,并输出结果
 7 # 5)    将 name 变量对应的值根据 “l” 分割,并输出结果。
 8 # 6)    将 name 变量对应的值变大写,并输出结果

 9 # 7)    将 name 变量对应的值变小写,并输出结果

10 # 8)    请输出 name 变量对应的值的第 2 个字符?
11 # 9)    请输出 name 变量对应的值的前 3 个字符?
12 # 10)    请输出 name 变量对应的值的后 2 个字符?

13 # 11)    请输出 name 变量对应的值中 “e” 所在索引位置?

14 # 12)    获取子序列,去掉最后一个字符。如: oldboy 则获取 oldbo
15 # 写代码,有如下变量,请按照要求实现每个功能 （共6分，每小题各0.5分）
16 name = " aleX"
17 # 1)    移除 name 变量对应的值两边的空格,并输出处理结果
18 name = ' aleX'
19 a=name.strip()
20 print(a)
21 
22 # 2)    判断 name 变量对应的值是否以 "al" 开头,并输出结果

23 name=' aleX'
24 if name.startswith(name):
25     print(name)
26 else:
27     print('no')
28 
29 # 3)    判断 name 变量对应的值是否以 "X" 结尾,并输出结果

30 name=' aleX'
31 if name.endswith(name):
32     print(name)
33 else:
34     print('no')
35 
36 # 4)    将 name 变量对应的值中的 “l” 替换为 “p”,并输出结果
37 name=' aleX'
38 print(name.replace('l','p'))
39 
40 # 5)    将 name 变量对应的值根据 “l” 分割,并输出结果。
41 name=' aleX'
42 print(name.split('l'))
43 
44 # 6)    将 name 变量对应的值变大写,并输出结果

45 name=' aleX'
46 print(name.upper())
47 
48 # 7)    将 name 变量对应的值变小写,并输出结果

49 name=' aleX'
50 print(name.lower())
51 
52 # 8)    请输出 name 变量对应的值的第 2 个字符?
53 name=' aleX'
54 print(name[1])
55 
56 # 9)    请输出 name 变量对应的值的前 3 个字符?
57 name=' aleX'
58 print(name[:3])
59 
60 # 10)    请输出 name 变量对应的值的后 2 个字符?

61 name=' aleX'
62 print(name[-2:])
63 
64 # 11)    请输出 name 变量对应的值中 “e” 所在索引位置?

65 name=' aleX'
66 print(name.index('e'))
67 
68 # 12)    获取子序列,去掉最后一个字符。如: oldboy 则获取 oldbo。
69 name=' aleX'
70 a=name[:-1]
71 print(a)
    练习

     

4、列表
创建列表：
1
2
3
name_list = ['alex', 'seven', 'eric']
或
name_list ＝ list(['alex', 'seven', 'eric'])
空列表name_list=[]

列表里面可以存放数字，浮点数，字符串，对象等。

基本操作：

  • 索引
  • 1

     

  • 追加 
    列表名.append()表示向列表末尾增加一个元素；
列表名.extend()表示向列表添加多个元素，参数是一个列表；

列表名.insert()表示向列表添加1个元素，参数1是插入的索引位置，参数2是插入的内容；

     

  • 删除 
    列表名.remove()表示删除1个元素，参数是列表的其中之一，否则会报错；

 del 列表名 或 del 列表名[1] 表示删除一个列表或列表的一个元素；

列表名.pop()表示取出最后一个元素有返回值，无参；

     

  • 长度
  • 切片 
    列表名[:]表示从头到尾（可以用做拷贝一个新的）
列表名[1:3]表示从索引为1到3的元素
  • 循环
  • 成员关系符in和not in
  • 可以比较大小
  • 可以用+拼接两个列表
  • 列表*n

  • 列表名.sort()表示列表内的元素从小到大排列的意思

     列表名.sort(reverse=True)表示列表内的元素从大到小排列的意思

     列表名.reverse（）表示列表内的元素倒序排列的意思

     列表中的元素是字典时的排序需要匿名函数：

       列表名.sort(key=lambda x:x[‘name’])

  • 列表名.count（元素名）返回一个元素的索引；
  • 列表名.index（参1，参2，参3）参1是一个元素，参2和参3表示索引号，表示参1在参2和参3之间的索引号；
  •   1 class list(object):
  2     """
  3     list() -> new empty list
  4     list(iterable) -> new list initialized from iterable's items
  5     """
  6     def append(self, p_object): # real signature unknown; restored from __doc__
  7         """ L.append(object) -- append object to end """
  8         pass
  9 
 10     def count(self, value): # real signature unknown; restored from __doc__
 11         """ L.count(value) -> integer -- return number of occurrences of value """
 12         return 0
 13 
 14     def extend(self, iterable): # real signature unknown; restored from __doc__
 15         """ L.extend(iterable) -- extend list by appending elements from the iterable """
 16         pass
 17 
 18     def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
 19         """
 20         L.index(value, [start, [stop]]) -> integer -- return first index of value.
 21         Raises ValueError if the value is not present.
 22         """
 23         return 0
 24 
 25     def insert(self, index, p_object): # real signature unknown; restored from __doc__
 26         """ L.insert(index, object) -- insert object before index """
 27         pass
 28 
 29     def pop(self, index=None): # real signature unknown; restored from __doc__
 30         """
 31         L.pop([index]) -> item -- remove and return item at index (default last).
 32         Raises IndexError if list is empty or index is out of range.
 33         """
 34         pass
 35 
 36     def remove(self, value): # real signature unknown; restored from __doc__
 37         """
 38         L.remove(value) -- remove first occurrence of value.
 39         Raises ValueError if the value is not present.
 40         """
 41         pass
 42 
 43     def reverse(self): # real signature unknown; restored from __doc__
 44         """ L.reverse() -- reverse *IN PLACE* """
 45         pass
 46 
 47     def sort(self, cmp=None, key=None, reverse=False): # real signature unknown; restored from __doc__
 48         """
 49         L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*;
 50         cmp(x, y) -> -1, 0, 1
 51         """
 52         pass
 53 
 54     def __add__(self, y): # real signature unknown; restored from __doc__
 55         """ x.__add__(y) <==> x+y """
 56         pass
 57 
 58     def __contains__(self, y): # real signature unknown; restored from __doc__
 59         """ x.__contains__(y) <==> y in x """
 60         pass
 61 
 62     def __delitem__(self, y): # real signature unknown; restored from __doc__
 63         """ x.__delitem__(y) <==> del x[y] """
 64         pass
 65 
 66     def __delslice__(self, i, j): # real signature unknown; restored from __doc__
 67         """
 68         x.__delslice__(i, j) <==> del x[i:j]
 69                    
 70                    Use of negative indices is not supported.
 71         """
 72         pass
 73 
 74     def __eq__(self, y): # real signature unknown; restored from __doc__
 75         """ x.__eq__(y) <==> x==y """
 76         pass
 77 
 78     def __getattribute__(self, name): # real signature unknown; restored from __doc__
 79         """ x.__getattribute__('name') <==> x.name """
 80         pass
 81 
 82     def __getitem__(self, y): # real signature unknown; restored from __doc__
 83         """ x.__getitem__(y) <==> x[y] """
 84         pass
 85 
 86     def __getslice__(self, i, j): # real signature unknown; restored from __doc__
 87         """
 88         x.__getslice__(i, j) <==> x[i:j]
 89                    
 90                    Use of negative indices is not supported.
 91         """
 92         pass
 93 
 94     def __ge__(self, y): # real signature unknown; restored from __doc__
 95         """ x.__ge__(y) <==> x>=y """
 96         pass
 97 
 98     def __gt__(self, y): # real signature unknown; restored from __doc__
 99         """ x.__gt__(y) <==> x>y """
100         pass
101 
102     def __iadd__(self, y): # real signature unknown; restored from __doc__
103         """ x.__iadd__(y) <==> x+=y """
104         pass
105 
106     def __imul__(self, y): # real signature unknown; restored from __doc__
107         """ x.__imul__(y) <==> x*=y """
108         pass
109 
110     def __init__(self, seq=()): # known special case of list.__init__
111         """
112         list() -> new empty list
113         list(iterable) -> new list initialized from iterable's items
114         # (copied from class doc)
115         """
116         pass
117 
118     def __iter__(self): # real signature unknown; restored from __doc__
119         """ x.__iter__() <==> iter(x) """
120         pass
121 
122     def __len__(self): # real signature unknown; restored from __doc__
123         """ x.__len__() <==> len(x) """
124         pass
125 
126     def __le__(self, y): # real signature unknown; restored from __doc__
127         """ x.__le__(y) <==> x<=y """
128         pass
129 
130     def __lt__(self, y): # real signature unknown; restored from __doc__
131         """ x.__lt__(y) <==> x<y """
132         pass
133 
134     def __mul__(self, n): # real signature unknown; restored from __doc__
135         """ x.__mul__(n) <==> x*n """
136         pass
137 
138     @staticmethod # known case of __new__
139     def __new__(S, *more): # real signature unknown; restored from __doc__
140         """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
141         pass
142 
143     def __ne__(self, y): # real signature unknown; restored from __doc__
144         """ x.__ne__(y) <==> x!=y """
145         pass
146 
147     def __repr__(self): # real signature unknown; restored from __doc__
148         """ x.__repr__() <==> repr(x) """
149         pass
150 
151     def __reversed__(self): # real signature unknown; restored from __doc__
152         """ L.__reversed__() -- return a reverse iterator over the list """
153         pass
154 
155     def __rmul__(self, n): # real signature unknown; restored from __doc__
156         """ x.__rmul__(n) <==> n*x """
157         pass
158 
159     def __setitem__(self, i, y): # real signature unknown; restored from __doc__
160         """ x.__setitem__(i, y) <==> x[i]=y """
161         pass
162 
163     def __setslice__(self, i, j, y): # real signature unknown; restored from __doc__
164         """
165         x.__setslice__(i, j, y) <==> x[i:j]=y
166                    
167                    Use  of negative indices is not supported.
168         """
169         pass
170 
171     def __sizeof__(self): # real signature unknown; restored from __doc__
172         """ L.__sizeof__() -- size of L in memory, in bytes """
173         pass
174 
175     __hash__ = None
    list源码
     1 1. 有列表data=['alex',49,[1900,3,18]]，分别取出列表中的名字，年龄，出生的年，月，日赋值给不同的变量
 2 
 3 2. 用列表模拟队列
 4 
 5 3. 用列表模拟堆栈
 6 
 7 4. 有如下列表，请按照年龄排序（涉及到匿名函数）
 8 l=[
 9     {'name':'alex','age':84},
10     {'name':'oldboy','age':73},
11     {'name':'egon','age':18},
12 ]
13 答案：
14 l.sort(key=lambda item:item['age'])
15 print(l)
    练习

     

5、元祖tuple：无法变化
创建元祖：
1
2
3
ages = (11, 22, 33, 44, 55)
或
ages = tuple((11, 22, 33, 44, 55))
空元组： ages=()
1个元组：ages=(1，)
 
基本操作：
  • 索引 
    元组名[1]
  • 切片 
    元组名[:]表示从头到尾（可以用做拷贝一个新的）
    元组名[1:3]表示从索引为1到3的元素

     

  • 循环
  • 长度
  • 包含in和not in 
      1 lass tuple(object):
  2     """
  3     tuple() -> empty tuple
  4     tuple(iterable) -> tuple initialized from iterable's items
  5     
  6     If the argument is a tuple, the return value is the same object.
  7     """
  8     def count(self, value): # real signature unknown; restored from __doc__
  9         """ T.count(value) -> integer -- return number of occurrences of value """
 10         return 0
 11 
 12     def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
 13         """
 14         T.index(value, [start, [stop]]) -> integer -- return first index of value.
 15         Raises ValueError if the value is not present.
 16         """
 17         return 0
 18 
 19     def __add__(self, y): # real signature unknown; restored from __doc__
 20         """ x.__add__(y) <==> x+y """
 21         pass
 22 
 23     def __contains__(self, y): # real signature unknown; restored from __doc__
 24         """ x.__contains__(y) <==> y in x """
 25         pass
 26 
 27     def __eq__(self, y): # real signature unknown; restored from __doc__
 28         """ x.__eq__(y) <==> x==y """
 29         pass
 30 
 31     def __getattribute__(self, name): # real signature unknown; restored from __doc__
 32         """ x.__getattribute__('name') <==> x.name """
 33         pass
 34 
 35     def __getitem__(self, y): # real signature unknown; restored from __doc__
 36         """ x.__getitem__(y) <==> x[y] """
 37         pass
 38 
 39     def __getnewargs__(self, *args, **kwargs): # real signature unknown
 40         pass
 41 
 42     def __getslice__(self, i, j): # real signature unknown; restored from __doc__
 43         """
 44         x.__getslice__(i, j) <==> x[i:j]
 45                    
 46                    Use of negative indices is not supported.
 47         """
 48         pass
 49 
 50     def __ge__(self, y): # real signature unknown; restored from __doc__
 51         """ x.__ge__(y) <==> x>=y """
 52         pass
 53 
 54     def __gt__(self, y): # real signature unknown; restored from __doc__
 55         """ x.__gt__(y) <==> x>y """
 56         pass
 57 
 58     def __hash__(self): # real signature unknown; restored from __doc__
 59         """ x.__hash__() <==> hash(x) """
 60         pass
 61 
 62     def __init__(self, seq=()): # known special case of tuple.__init__
 63         """
 64         tuple() -> empty tuple
 65         tuple(iterable) -> tuple initialized from iterable's items
 66         
 67         If the argument is a tuple, the return value is the same object.
 68         # (copied from class doc)
 69         """
 70         pass
 71 
 72     def __iter__(self): # real signature unknown; restored from __doc__
 73         """ x.__iter__() <==> iter(x) """
 74         pass
 75 
 76     def __len__(self): # real signature unknown; restored from __doc__
 77         """ x.__len__() <==> len(x) """
 78         pass
 79 
 80     def __le__(self, y): # real signature unknown; restored from __doc__
 81         """ x.__le__(y) <==> x<=y """
 82         pass
 83 
 84     def __lt__(self, y): # real signature unknown; restored from __doc__
 85         """ x.__lt__(y) <==> x<y """
 86         pass
 87 
 88     def __mul__(self, n): # real signature unknown; restored from __doc__
 89         """ x.__mul__(n) <==> x*n """
 90         pass
 91 
 92     @staticmethod # known case of __new__
 93     def __new__(S, *more): # real signature unknown; restored from __doc__
 94         """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
 95         pass
 96 
 97     def __ne__(self, y): # real signature unknown; restored from __doc__
 98         """ x.__ne__(y) <==> x!=y """
 99         pass
100 
101     def __repr__(self): # real signature unknown; restored from __doc__
102         """ x.__repr__() <==> repr(x) """
103         pass
104 
105     def __rmul__(self, n): # real signature unknown; restored from __doc__
106         """ x.__rmul__(n) <==> n*x """
107         pass
108 
109     def __sizeof__(self): # real signature unknown; restored from __doc__
110         """ T.__sizeof__() -- size of T in memory, in bytes """
111         pass
    tuple源码
    #简单购物车,要求如下：
实现打印商品详细信息，用户输入商品名和购买个数，则将商品名，价格，购买个数加入购物列表，如果输入为空或其他非法输入则要求用户重新输入　　

msg_dic={
'apple':10,
'tesla':100000,
'mac':3000,
'lenovo':30000,
'chicken':10,
}


msg_dic={
'apple':10,
'tesla':100000,
'mac':3000,
'lenovo':30000,
'chicken':10,
}
goods_l=[]
while True:
    for key,item in msg_dic.items():
        print('name:{name} price:{price}'.format(price=item,name=key))
    choice=input('商品>>: ').strip()
    if not choice or choice not in msg_dic:continue
    count=input('购买个数>>: ').strip()
    if not count.isdigit():continue
    goods_l.append((choice,msg_dic[choice],count))

    print(goods_l)
    练习

     元组无法改变，那么怎么更新了，可以通过切片与+   。

  • In [5]: temp=('hhh','yyy','333',)

In [6]: temp=temp[:2]+('rrr')+temp[2:]
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-6-6aac021c153b> in <module>()
----> 1 temp=temp[:2]+('rrr')+temp[2:]

TypeError: can only concatenate tuple (not "str") to tuple

In [7]: temp=temp[:2]+('rrr',)+temp[2:]
  • 元组*n表示一个元组里面的元素*n. 
    In [3]: 8*(8)
Out[3]: 64

In [4]: 8*(8,)
Out[4]: (8, 8, 8, 8, 8, 8, 8, 8)

     

 

 

6、字典（无序）
创建字典： 
#定义：key必须是不可变类型，value可以是任意类型，，，
1
2
3
person = {"name": "mr.wu", 'age': 18}
或
person = dict({"name": "mr.wu", 'age': 18})

常用操作：

  • 索引
  • 新增
  • 删除
  • 循环
  • 长度
    • 键、值、键值对键keys()，值values()，键值对items()
  • 按key存取值：可存可取
  • 成员运算in和not in
  •   1 class dict(object):
  2     """
  3     dict() -> new empty dictionary
  4     dict(mapping) -> new dictionary initialized from a mapping object's
  5         (key, value) pairs
  6     dict(iterable) -> new dictionary initialized as if via:
  7         d = {}
  8         for k, v in iterable:
  9             d[k] = v
 10     dict(**kwargs) -> new dictionary initialized with the name=value pairs
 11         in the keyword argument list.  For example:  dict(one=1, two=2)
 12     """
 13 
 14     def clear(self): # real signature unknown; restored from __doc__
 15         """ 清除内容 """
 16         """ D.clear() -> None.  Remove all items from D. """
 17         pass
 18 
 19     def copy(self): # real signature unknown; restored from __doc__
 20         """ 浅拷贝 """
 21         """ D.copy() -> a shallow copy of D """
 22         pass
 23 
 24     @staticmethod # known case
 25     def fromkeys(S, v=None): # real signature unknown; restored from __doc__
 26         """
 27         dict.fromkeys(S[,v]) -> New dict with keys from S and values equal to v.
 28         v defaults to None.
 29         """
 30         pass
 31 
 32     def get(self, k, d=None): # real signature unknown; restored from __doc__
 33         """ 根据key获取值，d是默认值 """
 34         """ D.get(k[,d]) -> D[k] if k in D, else d.  d defaults to None. """
 35         pass
 36 
 37     def has_key(self, k): # real signature unknown; restored from __doc__
 38         """ 是否有key """
 39         """ D.has_key(k) -> True if D has a key k, else False """
 40         return False
 41 
 42     def items(self): # real signature unknown; restored from __doc__
 43         """ 所有项的列表形式 """
 44         """ D.items() -> list of D's (key, value) pairs, as 2-tuples """
 45         return []
 46 
 47     def iteritems(self): # real signature unknown; restored from __doc__
 48         """ 项可迭代 """
 49         """ D.iteritems() -> an iterator over the (key, value) items of D """
 50         pass
 51 
 52     def iterkeys(self): # real signature unknown; restored from __doc__
 53         """ key可迭代 """
 54         """ D.iterkeys() -> an iterator over the keys of D """
 55         pass
 56 
 57     def itervalues(self): # real signature unknown; restored from __doc__
 58         """ value可迭代 """
 59         """ D.itervalues() -> an iterator over the values of D """
 60         pass
 61 
 62     def keys(self): # real signature unknown; restored from __doc__
 63         """ 所有的key列表 """
 64         """ D.keys() -> list of D's keys """
 65         return []
 66 
 67     def pop(self, k, d=None): # real signature unknown; restored from __doc__
 68         """ 获取并在字典中移除 """
 69         """
 70         D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
 71         If key is not found, d is returned if given, otherwise KeyError is raised
 72         """
 73         pass
 74 
 75     def popitem(self): # real signature unknown; restored from __doc__
 76         """ 获取并在字典中移除 """
 77         """
 78         D.popitem() -> (k, v), remove and return some (key, value) pair as a
 79         2-tuple; but raise KeyError if D is empty.
 80         """
 81         pass
 82 
 83     def setdefault(self, k, d=None): # real signature unknown; restored from __doc__
 84         """ 如果key不存在，则创建，如果存在，则返回已存在的值且不修改 """
 85         """ D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D """
 86         pass
 87 
 88     def update(self, E=None, **F): # known special case of dict.update
 89         """ 更新
 90             {'name':'alex', 'age': 18000}
 91             [('name','sbsbsb'),]
 92         """
 93         """
 94         D.update([E, ]**F) -> None.  Update D from dict/iterable E and F.
 95         If E present and has a .keys() method, does:     for k in E: D[k] = E[k]
 96         If E present and lacks .keys() method, does:     for (k, v) in E: D[k] = v
 97         In either case, this is followed by: for k in F: D[k] = F[k]
 98         """
 99         pass
100 
101     def values(self): # real signature unknown; restored from __doc__
102         """ 所有的值 """
103         """ D.values() -> list of D's values """
104         return []
105 
106     def viewitems(self): # real signature unknown; restored from __doc__
107         """ 所有项，只是将内容保存至view对象中 """
108         """ D.viewitems() -> a set-like object providing a view on D's items """
109         pass
110 
111     def viewkeys(self): # real signature unknown; restored from __doc__
112         """ D.viewkeys() -> a set-like object providing a view on D's keys """
113         pass
114 
115     def viewvalues(self): # real signature unknown; restored from __doc__
116         """ D.viewvalues() -> an object providing a view on D's values """
117         pass
118 
119     def __cmp__(self, y): # real signature unknown; restored from __doc__
120         """ x.__cmp__(y) <==> cmp(x,y) """
121         pass
122 
123     def __contains__(self, k): # real signature unknown; restored from __doc__
124         """ D.__contains__(k) -> True if D has a key k, else False """
125         return False
126 
127     def __delitem__(self, y): # real signature unknown; restored from __doc__
128         """ x.__delitem__(y) <==> del x[y] """
129         pass
130 
131     def __eq__(self, y): # real signature unknown; restored from __doc__
132         """ x.__eq__(y) <==> x==y """
133         pass
134 
135     def __getattribute__(self, name): # real signature unknown; restored from __doc__
136         """ x.__getattribute__('name') <==> x.name """
137         pass
138 
139     def __getitem__(self, y): # real signature unknown; restored from __doc__
140         """ x.__getitem__(y) <==> x[y] """
141         pass
142 
143     def __ge__(self, y): # real signature unknown; restored from __doc__
144         """ x.__ge__(y) <==> x>=y """
145         pass
146 
147     def __gt__(self, y): # real signature unknown; restored from __doc__
148         """ x.__gt__(y) <==> x>y """
149         pass
150 
151     def __init__(self, seq=None, **kwargs): # known special case of dict.__init__
152         """
153         dict() -> new empty dictionary
154         dict(mapping) -> new dictionary initialized from a mapping object's
155             (key, value) pairs
156         dict(iterable) -> new dictionary initialized as if via:
157             d = {}
158             for k, v in iterable:
159                 d[k] = v
160         dict(**kwargs) -> new dictionary initialized with the name=value pairs
161             in the keyword argument list.  For example:  dict(one=1, two=2)
162         # (copied from class doc)
163         """
164         pass
165 
166     def __iter__(self): # real signature unknown; restored from __doc__
167         """ x.__iter__() <==> iter(x) """
168         pass
169 
170     def __len__(self): # real signature unknown; restored from __doc__
171         """ x.__len__() <==> len(x) """
172         pass
173 
174     def __le__(self, y): # real signature unknown; restored from __doc__
175         """ x.__le__(y) <==> x<=y """
176         pass
177 
178     def __lt__(self, y): # real signature unknown; restored from __doc__
179         """ x.__lt__(y) <==> x<y """
180         pass
181 
182     @staticmethod # known case of __new__
183     def __new__(S, *more): # real signature unknown; restored from __doc__
184         """ T.__new__(S, ...) -> a new object with type S, a subtype of T """
185         pass
186 
187     def __ne__(self, y): # real signature unknown; restored from __doc__
188         """ x.__ne__(y) <==> x!=y """
189         pass
190 
191     def __repr__(self): # real signature unknown; restored from __doc__
192         """ x.__repr__() <==> repr(x) """
193         pass
194 
195     def __setitem__(self, i, y): # real signature unknown; restored from __doc__
196         """ x.__setitem__(i, y) <==> x[i]=y """
197         pass
198 
199     def __sizeof__(self): # real signature unknown; restored from __doc__
200         """ D.__sizeof__() -> size of D in memory, in bytes """
201         pass
202 
203     __hash__ = None
    dict

     

    1 有如下值集合 [11,22,33,44,55,66,77,88,99,90...]，将所有大于 66 的值保存至字典的第一个key中，将小于 66 的值保存至第二个key的值中

即： {'k1': 大于66的所有值, 'k2': 小于66的所有值}




a={'k1':[],'k2':[]}
c=[11,22,33,44,55,66,77,88,99,90]
for i in c:
    if i>66:
        a['k1'].append(i)
    else:
        a['k2'].append(i)
print(a)
    练习1
    2 统计s='hello alex alex say hello sb sb'中每个单词的个数

结果如：{'hello': 2, 'alex': 2, 'say': 1, 'sb': 2}


s='hello alex alex say hello sb sb'

l=s.split()
dic={}
for item in l:
    if item in dic:
        dic[item]+=1
    else:
        dic[item]=1
print(dic
    练习2
    s='hello alex alex say hello sb sb'
dic={}
words=s.split()
print(words)
for word in words: #word='alex'
    dic[word]=s.count(word)
    print(dic)


#利用setdefault解决重复赋值
'''
setdefault的功能
1：key存在，则不赋值，key不存在则设置默认值
2：key存在，返回的是key对应的已有的值，key不存在，返回的则是要设置的默认值
d={}
print(d.setdefault('a',1)) #返回1

d={'a':2222}
print(d.setdefault('a',1)) #返回2222
'''
s='hello alex alex say hello sb sb'
dic={}
words=s.split()
for word in words: #word='alex'
    dic.setdefault(word,s.count(word))
    print(dic)



#利用集合，去掉重复，减少循环次数
s='hello alex alex say hello sb sb'
dic={}
words=s.split()
words_set=set(words)
for word in words_set:
    dic[word]=s.count(word)
    print(dic)
    setdefault的功能

     

七 集合 

复制代码
#作用：去重，关系运算，

#定义：
            知识点回顾
            可变类型是不可hash类型
            不可变类型是可hash类型

#定义集合:
            集合：可以包含多个元素，用逗号分割，
            集合的元素遵循三个原则：
             1：每个元素必须是不可变类型(可hash，可作为字典的key)
             2:没有重复的元素
             3：无序

注意集合的目的是将不同的值存放到一起，不同的集合间用来做关系运算，无需纠结于集合中单个值
 

#优先掌握的操作：
#1、长度len
#2、成员运算in和not in

#3、|合集
#4、&交集
#5、-差集
#6、^对称差集
#7、==
#8、父集：>,>= 
#9、子集：<,<=    
一.关系运算
　　有如下两个集合，pythons是报名python课程的学员名字集合，linuxs是报名linux课程的学员名字集合
　　pythons={'alex','egon','yuanhao','wupeiqi','gangdan','biubiu'}
　　linuxs={'wupeiqi','oldboy','gangdan'}
　　1. 求出即报名python又报名linux课程的学员名字集合
　　2. 求出所有报名的学生名字集合
　　3. 求出只报名python课程的学员名字
　　4. 求出没有同时这两门课程的学员名字集合
练习1
# 有如下两个集合，pythons是报名python课程的学员名字集合，linuxs是报名linux课程的学员名字集合
pythons={'alex','egon','yuanhao','wupeiqi','gangdan','biubiu'}
linuxs={'wupeiqi','oldboy','gangdan'}
# 求出即报名python又报名linux课程的学员名字集合
print(pythons & linuxs)
# 求出所有报名的学生名字集合
print(pythons | linuxs)
# 求出只报名python课程的学员名字
print(pythons - linuxs)
# 求出没有同时这两门课程的学员名字集合
print(pythons ^ linuxs)
练习2
二.去重

　　 1. 有列表l=['a','b',1,'a','a']，列表元素均为可hash类型，去重，得到新列表,且新列表无需保持列表原来的顺序

　　 2.在上题的基础上，保存列表原来的顺序

　　 3.去除文件中重复的行，肯定要保持文件内容的顺序不变
　　 4.有如下列表，列表元素为不可hash类型，去重，得到新列表，且新列表一定要保持列表原来的顺序

l=[
    {'name':'egon','age':18,'sex':'male'},
    {'name':'alex','age':73,'sex':'male'},
    {'name':'egon','age':20,'sex':'female'},
    {'name':'egon','age':18,'sex':'male'},
    {'name':'egon','age':18,'sex':'male'},
去重
#去重,无需保持原来的顺序
l=['a','b',1,'a','a']
print(set(l))

#去重,并保持原来的顺序
#方法一:不用集合
l=[1,'a','b',1,'a']

l1=[]
for i in l:
    if i not in l1:
        l1.append(i)
print(l1)
#方法二:借助集合
l1=[]
s=set()
for i in l:
    if i not in s:
        s.add(i)
        l1.append(i)

print(l1)


#同上方法二,去除文件中重复的行
import os
with open('db.txt','r',encoding='utf-8') as read_f,\
        open('.db.txt.swap','w',encoding='utf-8') as write_f:
    s=set()
    for line in read_f:
        if line not in s:
            s.add(line)
            write_f.write(line)
os.remove('db.txt')
os.rename('.db.txt.swap','db.txt')

#列表中元素为可变类型时,去重,并且保持原来顺序
l=[
    {'name':'egon','age':18,'sex':'male'},
    {'name':'alex','age':73,'sex':'male'},
    {'name':'egon','age':20,'sex':'female'},
    {'name':'egon','age':18,'sex':'male'},
    {'name':'egon','age':18,'sex':'male'},
]
# print(set(l)) #报错:unhashable type: 'dict'
s=set()
l1=[]
for item in l:
    val=(item['name'],item['age'],item['sex'])
    if val not in s:
        s.add(val)
        l1.append(item)

print(l1)






#定义函数,既可以针对可以hash类型又可以针对不可hash类型
def func(items,key=None):
    s=set()
    for item in items:
        val=item if key is None else key(item)
        if val not in s:
            s.add(val)
            yield item

print(list(func(l,key=lambda dic:(dic['name'],dic['age'],dic['sex']))))
练习3
PS：循环，range，continue 和 break
 

三、其他：

1、for循环
用户按照顺序循环可迭代对象中的内容，
PS：break、continue
1
2
3
li = [11,22,33,44]
for item in li:
    print item
2、enumrate
为可迭代的对象添加序号
1
2
3
li = [11,22,33]
for k,v in enumerate(li, 1):
    print(k,v)
3、range和xrange
指定范围，生成指定的数字
1
2
3
4
5
6
7
8
print range(1, 10)
# 结果：[1, 2, 3, 4, 5, 6, 7, 8, 9]
 
print range(1, 10, 2)
# 结果：[1, 3, 5, 7, 9]
 
print range(30, 0, -2)
# 结果：[30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2]　　

练习题

一、元素分类

有如下值集合 [11,22,33,44,55,66,77,88,99,90...]，将所有大于 66 的值保存至字典的第一个key中，将小于 66 的值保存至第二个key的值中。
即： {'k1': 大于66的所有值, 'k2': 小于66的所有值}

二、查找
查找列表中元素，移除每个元素的空格，并查找以 a或A开头 并且以 c 结尾的所有元素。
    li = ["alec", " aric", "Alex", "Tony", "rain"]
    tu = ("alec", " aric", "Alex", "Tony", "rain") 
    dic = {'k1': "alex", 'k2': ' aric',  "k3": "Alex", "k4": "Tony"}
posted @ 2018-04-05 19:33  不变的真理  阅读(889)  评论(0)    收藏  举报