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【Python3之基本数据类型,基本运算】

一、基本数据类型

1.字符串

类:str

方法:选中str,按住command(ctrl)+左键跳转至对应的方法

 

  • 创建
a = "hexin"
a = str('hexin')
  • 转换
age = 19
new_age = str(age)
  • 字符串的拼接
name = 'hexin'
gender = '女'
new_str = name + gender
print(new_str)

 

  • 字符串格式化  占位符
# name = '我叫李杰,性别:%s,我今年%s岁,我在说谎!'
# new_str = name %('男',19,)
# print(new_str)

name = '我叫李杰,性别:%s,我今年%s岁,我在说谎!' %('男',19,)
print(name)

 

判断子序列是否在其中

content = "123 前几天去泰国玩姑娘,一不小心染上了病,他的内心活动是,真该多来几个"

if "前几天去" in content:
print('包含敏感字符')
else:
print(content)

 

  • 移除空白  strip 
a = '   he xin  '
print(a)
new_a=a.strip()    #左右
new_a1=a.lstrip()       #左
new_a2=a.rstrip()  #右
print(new_a)
print(new_a1)
print(new_a2)

输出

   he xin  
he xin
he xin  
   he xin
  • 分割
user_info = "ex|in s123 9"
v1 = user_info.split('|')
v2 = user_info.split('|',1)
v3 = user_info.rsplit(' ',1)
print(v1)
print(v2)
print(v3)

输出

['ex', 'in s123 9']
['ex', 'in s123 9']
['ex|in s123', '9']

 

  • 长度    len()
user_info = "ex|in s123 9"
v1 = len(user_info)
print(v1)

输出

12

 

  • 索引
val = "exin"
v = val[0]
print(v)

val = input('>>>')
i = 0
while i < len(val):
    print(val[i])
    i += 1

输出

e
>>>iii
i
i
i

 

  • 切片
name = '我叫李杰,性别我今年岁,我在说谎!'
print(name[0])
print(name[0:2])
print(name[5:9])
print(name[5:])
print(name[5:-2])
print(name[-2:])

输出

我
我叫
性别我今
性别我今年岁,我在说谎!
性别我今年岁,我在说
谎!

 

 

字符串常用方法归纳如下:

  • 1)capitalize

功能:实现字符串首字母大写,自身不变,会生成一个新的值

 例子:

1 #!/usr/bin/env python
2 # -*- coding:utf-8 -*-
3 name = 'hexin'
4 v = name.capitalize() #调用str类,执行其中capitalize的方法
5 print(v)

输出:

hexin
Hexin

 

  • 2)casefold

功能:将所有大写变成小写,另外支持多门语言变化

例子:

1 name = 'HexIn'
2 v = name.casefold()
3 print(name)
4 print(v)

输出:

HexIn
hexin

 

  • 3)lower,upper

功能:

lower:将所有的大写变小写,局限英文

upper:将所有小写变大写

 

lower

例子:

1 name = 'HeXin'
2 v = name.lower()
3 print(name)
4 print(v)

结果:

HeXin
hexin

 

  • 4)center

功能:文本居中,空白处填充字符

参数1:表示总长度;参数2:空白处填充的字符(长度为1)

center

例子:

1 name = 'HeXin'
2 v = name.center(20,'*')
3 print(name)
4 print(v)

输出:

HeXin
*******HeXin********

 

  • 5)count

功能:表示要查找的子序列在字符串中出现的次数

参数1:要查找的值(子序列);参数2:起始位置(索引);参数3:结束位置(索引)

count

例子:

1 name = 'HeXinddaklfjsl;dfjcnljdajsflajdf'
2 v = name.count('a')
3 i = name.count('a',0,15)
4 print(name)
5 print(v)
6 print(i)

输出:

3
1

 

  • 6)endswith

功能:判断是否以xx结尾

参数1:判断值;参数2,3:起始和结束的位置(个数)

endswith

例子:

1 name = 'HeXinddaklfjsl;dfjcnljdajsflajdf'
2 v = name.endswith('df')
3 i = name.endswith('n',0,5)
4 print(name)
5 print(v)
6 print(i)

输出:

HeXinddaklfjsl;dfjcnljdajsflajdf
True
True

 

  • 7)expandtabs

功能:找到制表符\t,进行替换(包含前面的值)

expandtabs

例子:

1 name = "al\te\tx\nalex\tuu\tkkk"
2 v = name.expandtabs(5)  #包含前面的值,5个长度
3 print(v)

输出:

al   e    x
alex uu   kkk

 

  • 8)find

功能:找到指定子序列的索引位置,不存在返回-1

find

例子:

1 name = 'hexin'
2 v = name.find('0')
3 i = name.find('x')
4 print(v)
5 print(i)

输出:

-1
2

 

  • 9)format,%s,format_map

功能:字符串格式化

format

 

format_map

例子:

 1 tpl1 = "我是:%s;年龄:%s;性别:%s" %( 'hexin',18,'man')
 2 print(tpl1)
 3 
 4 tpl2 = "我是:{0};年龄:{1};性别:{2}"
 5 v2 = tpl2.format("李杰",19,'都行')
 6 print(v2)
 7 
 8 tpl3 = "我是:{name};年龄:{age};性别:{gender}"
 9 v3 = tpl3.format(name='李杰',age=19,gender='随意')
10 print(v3)
11 
12 tpl4 = "我是:{name};年龄:{age};性别:{gender}"
13 v4 = tpl4.format_map({'name':"李杰",'age':19,'gender':'中'})
14 print(v4)

输出:

我是:hexin;年龄:18;性别:man
我是:李杰;年龄:19;性别:都行
我是:李杰;年龄:19;性别:随意
我是:李杰;年龄:19;性别:中

 

  • 10)isalnum

功能:是否是数字或汉字

isalnum

例子:

1 name = 'hexin0好'
2 v = name.isalnum()
3 print(v)

输出:

True

 

  • 11)isdecimal,isdigit,isnumeric

功能:是否是数字

isalnum
isdecimal
isdigit

 

例子:

1 num = '二'
2 v1 = num.isdecimal() # '123'
3 v2 = num.isdigit()   # '123','②'
4 v3 = num.isnumeric() # '123','二','②'
5 print(v1,v2,v3)

输出:

False False True

 

  • 12)isidentifer

功能:是否是有效的标识符

isidentifier

例子:

1 n = '1name'
2 u = 'name'
3 v = n.isidentifier()
4 i = u.isidentifier()
5 print(v)
6 print(i)

输出:

False
True

 

  • 13)islower(isupper)

功能:是否全部是小写(大写)

islower

例子:

1 name = 'hexin'
2 name1 = 'Hexin'
3 v = name.islower()
4 i = name1.islower()
5 print(v)
6 print(i)

输出:

True
False

 

  • 14)isprintable

功能:是否包含隐含的XX(包含\n,\t等不可见字符为False)

 

isprintable

例子:

1 name = 'hexindas\talj,hexin'
2 v = name.isprintable()
3 print(v)

输出:

False

 

  • 15)join

功能:元素拼接

join

例子:

1 name = 'hexin'
2 
3 v = "_".join(name) # 内部循环每个元素
4 print(v)
5 
6 name_list = ['1','2','3','4']
7 v = "+".join(name_list)
8 print(v)

输出:

h_e_x_i_n
1+2+3+4

 

  • 16)rjust,ljust

功能:左右填充,类似center

ljust

例子:

1 name = 'hexin'
2 v = name.ljust(14,'*')
3 i = name.rjust(6,'*')
4 print(v)
5 print(i)

输出

hexin*********
*hexin

 

  • 17)maketrans,translate

功能:创建对应关系,翻译转换

maketrans

例子:

1 m = str.maketrans('aeiou','12345') # 对应关系
2 name = "akpsojfasdufasdlkfj8ausdfakjsdfl;kjer09asdf"
3 v = name.translate(m)
4 print(v)

输出:

1kps4jf1sd5f1sdlkfj815sdf1kjsdfl;kj2r091sdf

 

  • 18)partition

功能:分割,保留分割的元素

partition

例子:

1 content = "9SB6SB6"
2 v = content.partition('SB') # partition
3 print(v)

输出:

('9', 'SB', '6SB6')

 

  • 19)replace

功能:替换

replace

例子:

1 content = "1SB2SB3SB4"
2 v = content.replace('SB','Love')
3 print(v)
4 v = content.replace('SB','Love',1)
5 print(v)

输出:

1Love2Love3Love4
1Love2SB3SB4

 

  • 20)strip

功能:移除空白,\n,\t, 自定义

strip

 

例子:

1 name = 'hexin \t'
2 v = name.strip() # 空白,\n,\t
3 print(v)

输出:

hexin

 

  • 21)zfill

功能:填充0

zfill

例子:

1 name = 'hexin'
2 v = name.zfill(20)
3 print(v)

输出:

000000000000000hexin

 

2.整数

类int

  • 1)bit_length

功能:当前整数的二进制表示的最少位数

bit_length

例子:

age = 4 # 100
print(age.bit_length())

输出:

3

 

  • 2)to_bytes

功能:获取当前数据的字节表示

to_bytes

例子:

age = 15
v = age.to_bytes(10,byteorder='big')
v = age.to_bytes(10,byteorder='little')
print(v)

输出:

b'\x0f\x00\x00\x00\x00\x00\x00\x00\x00\x00'

 

3.list列表

类list

可变类型

 

  • 创建
a = ['狗','eric',123]
a = list(['狗','eric',123])
print(a)

输出

['狗', 'eric', 123]

 

  • in判断
a = ['狗','eric',123]
if 'eric' in a:
    print(True)
print(a)

输出

True
['狗', 'eric', 123]

 

  • 索引
val = a[0]

 

  • 长度
val = len(a)

 

  • 切片
a = ['狗','eric',123]
v = a[0::2]
print(v)

输出

['狗', 123]

 

补充:

  • 1)append

功能:追加

append

例子:

user_list = ['tom','刘','jack','n'] # 可变类型
user_list.append('hex')
print(user_list)

输出

['tom', '刘', 'jack', 'n', 'hex']

 

  • 2)clear

功能:清空

例子:

user_list = ['tom','刘','jack','n'] # 可变类型
user_list.clear()
print(user_list)

输出:

[]

 

  • 3)copy

功能:浅拷贝

例子:

user_list = ['tom','刘','jack','n'] 
t = user_list.copy()
print(user_list)
print(t)

输出:

['tom', '刘', 'jack', 'n']
['tom', '刘', 'jack', 'n']

 

  • 4)count

功能:计数

例子:

user_list = ['tom','n','刘','jack','n','n']
t = user_list.count('n')
print(user_list)
print(t)

输出:

['tom', 'n', '刘', 'jack', 'n', 'n']
3

 

  • 5)extend

功能:扩展原列表

例子:

user_list = ['tom','n','刘','jack','n','n']
user_list.extend('9')
print(user_list)

输出:

['tom', 'n', '刘', 'jack', 'n', 'n', '9']

 

  • 6)index

功能:查找元素索引,没有报错

例子:

user_list = ['tom','n','刘','jack','n','n']
v = user_list.index('n')
print(v)

输出:

1

 

  • 7)pop

功能:删除并获取元素,索引

例子:

user_list = ['tom','n','刘','jack','n','n']
v = user_list.pop(1)
print(v)
print(user_list)

输出:

n
['tom', '刘', 'jack', 'n', 'n']

 

  • 8)remove

功能:删除,值

例子:

user_list = ['tom','n','刘','jack','n','n']
user_list.remove('n')
print(user_list)

输出:

['tom', '刘', 'jack', 'n', 'n']

 

  • 9)reverse

功能:翻转

例子:

user_list = ['tom','n','刘','jack','n','n']
user_list.reverse()
print(user_list)

输出:

['n', 'n', 'jack', '刘', 'n', 'tom']

 

  • 10)sort

功能:排序

例子:

num = [11,2,3,6,111]
num.sort()
print(num)
num.sort(reverse=True)
print(num)

输出:

[2, 3, 6, 11, 111]
[111, 11, 6, 3, 2]

 

4.range

  • 1)创建

py2.7:立即生成数字

range(1,11) # 生成 1,23,,4,56.10

 

py3:不会立即生成,只有循环迭代,才一个个生成;

for i in range(1,11): 
    print(i)

for j in range(1,11,2): 
    print(j)

for k in range(10,0,-1): 
    print(k)
1
2
3
4
5
6
7
8
9
10
1
3
5
7
9
10
9
8
7
6
5
4
3
2
1

 

例子

# li = ['eric','alex','tony']
# for i in range(0,len(li)):
# ele = li[i]
# print(ele)


li = ['eric','alex','tony']
for i in li:
print(i)

# for i in range(0,len(li)):
# print(i+1,li[i])

输出

eric
alex
tony

5.enumerate

功能:额外生成一列有序的数字

例子

li = ['eric','alex','tony']
for i,ele in enumerate(li,1):
    print(i,ele)

#1 eric
#2 alex
#3 tony
li = ['eric','alex','tony']
for i,ele in enumerate(li,1):
    print(i,ele)

v = input('请输入商品序号:')
v = int(v)
item = li[v-1]
print(item)


#1 eric
#2 alex
#3 tony
#请输入商品序号:1
#eric

 

6.tuple元组

不可被修改类型,儿子不可被修改,孙子可以

  • 1)创建
user_tuple = ('hex','eric','seven','hex')
  • 2)count

功能:获取个数

user_tuple = ('hex','eric','seven','hex')
v = user_tuple.count('hex')
print(v)

#2
  • 3)index

功能:获取值得第一个索引位置

user_tuple = ('hex','eric','seven','hex')
v = user_tuple.index('hex')
print(v)

#0

 

  • 4)注意:元组最后加逗号

例子

li = ('hx',)
print(li)

 

  • 5)本身不可修改,但是孙子可以

user_tuple = ('alex','eric','seven',['1','2','3'],'a4')
# user_tuple[0] = 123 执行错误
# user_tuple[3] = [11,22,33] 执行错误
user_tuple[3][1] = '0'
print(user_tuple)

 

7.dict

可变类型

  • 创建
 v = { 'name': 'al','password': '123123'}

 

  • 1)clear

功能:清空

dic = {'k1':'v1','k2':'v2'}
dic.clear()
print(dic)

 

  • 2)copy

功能:浅拷贝

dic = {'k1':'v1','k2':'v2'}
v = dic.copy()
print(v)

 

  • 3)get

功能:根据key获取指定value,不存在不报错

dic = {'k1':'v1','k2':'v2'}
v = dic.get('k1111',1111)
print(v)

 

  • 4)pop

功能:删除并获取对应的value值

# dic = {'k1':'v1','k2':'v2'}
# v = dic.pop('k1')
# print(dic)
# print(v)

输出:

{'k2': 'v2'}
v1

 

  • 5)popitem

功能:随机删除键值对,并获取到删除的键值

dic = {'k1':'v1','k2':'v2'}
v = dic.popitem()
print(dic)
print(v)

输出:

{'k1': 'v1'}
('k2', 'v2')

 

dic = {'k1':'v1','k2':'v2'}
k,v = dic.popitem() # ('k2', 'v2')
print(dic)
print(k,v)

输出:

{'k2': 'v2'}
k1 v1

 

dic = {'k1':'v1','k2':'v2'}
v = dic.popitem() # ('k2', 'v2')
print(dic)
print(v[0],v[1])

输出:

{'k1': 'v1'}
k2 v2

 

  • 6)setdefault

功能:增加,如果不存在即删除

dic = {'k1':'v1','k2':'v2'}
dic.setdefault('k3','v3')
print(dic)
dic.setdefault('k1','1111111')
print(dic)

输出:

{'k2': 'v2', 'k1': 'v1', 'k3': 'v3'}
{'k2': 'v2', 'k1': 'v1', 'k3': 'v3'}

 

  • 7)update

功能:批量增加或修改

dic = {'k1':'v1','k2':'v2'}
dic.update({'k3':'v3','k1':'v24'})
print(dic)

输出:

{'k1': 'v24', 'k2': 'v2', 'k3': 'v3'}

 

  • 8)fromkeys

功能:从序列键和值设置为value来创建一个新的字典。

例子:

dic = dict.fromkeys(['k1','k2','k3'],123)
dic['k1'] = 'asdfjasldkf'
print(dic)

输出:

{'k2': 123, 'k1': 'asdfjasldkf', 'k3': 123}

 

8.set

集合,不可重复列表,可变类型。

 

  • 1)创建
s1 = {"alex",'eric','tony'}
print(type(s1))
print(s1)

输出:

<class 'set'>
{'alex', 'eric', 'tony'}

 

  • 2)difference

功能:输出s1中存在,s2中不存在的值

s1 = {"alex",'eric','tony','ii'}
s2 = {"alex",'eric','tony','hexin'}
v = s1.difference(s2)
print(v)

 输出:

{'ii'}

 

  • 3)difference_update

功能:s1中存在,s2中不存在,然后对s1清空,然后在重新赋值

s1 = {"alex",'eric','tony','ii'}
s2 = {"alex",'eric','tony','hexin'}
s1.difference_update(s2)
print(s1)

输出:

{'ii'}

 

  • 4)symmetric_difference

功能:s1中存在,s2中不存在的值及s2中存在,s1中不存在的值

s1 = {"alex",'eric','tony','ii'}
s2 = {"alex",'eric','tony','hexin'}
v = s1.symmetric_difference(s2)
print(v)
{'ii', 'hexin'}

 

  • 5)intersection

功能:交集

s1 = {"alex",'eric','tony','ii'}
s2 = {"alex",'eric','tony','hexin'}
v = s1.intersection(s2)
print(v)

输出:

{'eric', 'alex', 'tony'}

 

  • 6)union

功能:并集

s1 = {"alex",'eric','tony','ii'}
s2 = {"alex",'eric','tony','hexin'}
v = s1.union(s2)
print(v)

输出:

{'alex', 'hexin', 'eric', 'ii', 'tony'}

 

  • 7)discard

功能:移除

s1 = {"alex",'eric','tony','ii'}
s2 = {"alex",'eric','tony','hexin'}
s1.discard('alex')
print(s1)

输出:

{'eric', 'tony', 'ii'}

 

  • 8)update

功能:添加

s1 = {"alex",'eric','tony','李泉','李泉11'}
s1.update({'alex','123123','fff'})
print(s1)

输出:

{'fff', '李泉', '123123', 'tony', 'alex', 'eric', '李泉11'}

 

9.布尔值

  • 创建
a = True
b = Flase
 
  • 转换
数字转换只有0是Flase,字符串只有""为Flase
v = bool(12)
print(v)

二、基本运算

1.算数运算:

注:运算符的执行顺序,从前往后

 

2.比较运算:

 

3.赋值运算:

 

4.逻辑运算:

 

5.成员运算:

 

posted on 2017-06-19 22:04 小火星_Hirsi 阅读(...) 评论(...) 编辑 收藏