Python数据转换与运算

整形 int

增删改

增
　　a = 1
改
　　a = 2
删
　　del a

转换

a = 1
str
　　str(a)  # '1'
list
　　list(a)  # TypeError: 'int' object is not iterable
　　[a]  # [1]
dict
　　dict(a)  # TypeError: 'int' object is not iterable
　　res = {}
　　res.setdefault(a)  # {1:None}
tuple
　　tuple(a)  # TypeError: 'int' object is not iterable
　　(a,)  # (1,)
set
　　set(a)  # TypeError: 'int' object is not iterable
　　{a}  # {1}

运算

float
　　a = 1
　　b = 2.1
　　print(a+b)
　　print(a-b)
　　print(a*b)
　　print(a/b)  a/0  # ZeroDivisionError: division by zero
str
　　a = 1
　　b = '2'
　　print(a + b)  # TypeError: unsupported operand type(s) for +: 'int' and 'str'
　　b = 'addsad'
　　print(a + b)  # TypeError: unsupported operand type(s) for +: 'int' and 'str'
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'int' and 'str'
　　print(a * b)  # addsad
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'int' and 'str'
list
　　a = 2
　　b = [1,2,3]
　　print(a + b)  # TypeError: unsupported operand type(s) for +: 'int' and 'list'
　　print(a * b)  # [1, 2, 3, 1, 2, 3]
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'int' and 'list'
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'int' and 'list'
dict
　　a = 2
　　b = {'c': 1, 'd': 2}
　　print(a + b)  # TypeError: unsupported operand type(s) for +: 'int' and 'dict'
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'int' and 'dict'
　　print(a * b)  # TypeError: unsupported operand type(s) for *: 'int' and 'dict'
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'int' and 'dict'
tuple
　　a = 2
　　b = (1,2,3)
　　print(a + b)  # TypeError: unsupported operand type(s) for +: 'int' and 'tuple'
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'int' and 'tuple'
　　print(a * b)  # (1, 2, 3, 1, 2, 3)
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'int' and 'tuple'
set
　　a = 2
　　b = {1,2,3}
　　print(a + b)  # TypeError: unsupported operand type(s) for +: 'int' and 'set'
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'int' and 'set'
　　print(a * b)  # TypeError: unsupported operand type(s) for *: 'int' and 'set'
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'int' and 'set'

 

字符型 string

增删改

增
    a = 'dasd'
改
    a = 'dasdasd'
删
    del a

转换

a = '123'
int
　　print(int(a))  # 123
list
　　print(list(a))  # ['1','2','3']
　　[a]  # ['123']
dict
　　print(dict(a))  # ValueError: dictionary update sequence element #0 has length 1; 2 is required
　　res = {}　　
　　res.setdefault(a)  # {'123':None}
tuple
　　print(tuple(a))  # ('1', '2', '3')
　　(a,)  # ('123',)
set
　　print(set(a))  # {'1', '2', '3'}
　　{a}  # {'123'}

a = 'afasfa'
int
　　print(int(a))  # ValueError: invalid literal for int() with base 10: 'afasfa'
list
　　print(list(a))  # ['a', 'f', 'a', 's', 'f', 'a']
　　[a]  # ['afasfa']
dict
　　print(dict(a))  # ValueError: dictionary update sequence element #0 has length 1; 2 is required
　　res = {}
　　res.setdefault(a)  # {'afasfa':None}
tuple
　　print(tuple(a))  # ('a', 'f', 'a', 's', 'f', 'a')
　　(a)  # ('afasfa')
set
　　print(set(a))  # {'a', 's', 'f'}  集合去重
　　{a}  # {'afasfa'}

运算

int
   a = 'afasfa'
　　b = 2
　　print(a + b)  # TypeError: can only concatenate str (not "int") to str
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'str' and 'int'
　　print(a * b)  # afasfaafasfa
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'str' and 'int'
str
　　a = '2'
　　b = 'dada'
　　print(a + b)  # 2dada
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'str' and 'str'
　　print(a * b)  # TypeError: can't multiply sequence by non-int of type 'str'
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'str' and 'str'
list
　　a = 'asdad'
　　b = ['das','das','dasd']
　　print(a + b)  # TypeError: can only concatenate str (not "list") to str
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'str' and 'list'
　　print(a * b)  # TypeError: can't multiply sequence by non-int of type 'list'
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'str' and 'list'
dict
　　a = 'dasda'
　　b = {'sd':'dasd','dsad':'dad'}
　　print(a + b)  # TypeError: can only concatenate str (not "dict") to str
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'str' and 'dict'
　　print(a * b)  # TypeError: can't multiply sequence by non-int of type 'dict'
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'str' and 'dict'
tuple
　　a = 'dasda'
　　b = (1,'dasd','dasda')
　　print(a + b)  # TypeError: can only concatenate str (not "tuple") to str
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'str' and 'tuple'
　　print(a * b)  # TypeError: can't multiply sequence by non-int of type 'tuple'
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'str' and 'tuple'
set
　　a = 'dasd'
　　b = {'asda','dad','dada'}
　　print(a + b)  # TypeError: can only concatenate str (not "set") to str
　　print(a - b)  # TypeError: unsupported operand type(s) for -: 'str' and 'set'
　　print(a * b)  # TypeError: can't multiply sequence by non-int of type 'set'
　　print(a / b)  # TypeError: unsupported operand type(s) for /: 'str' and 'set'

 

列表list

 增删改

增
    a = ['1','2','3']
    a = a.append('4')  # ['1','2','3','4']
    a = a.insert(3,'4') # ['1','2','3','4']
    a = a.extend(['4'])  # ['1','2','3','4']
删　
　　 del a
　　 a.remove('1')  # ['2','3']
　　 a.pop(1)  # ['1','3']
　　 a.clear()  # []
改
　　a[1] = '3'  # ['1','3','3']

转换

a = ['1','2','3']
int
　　int(a)  # TypeError: int() argument must be a string, a bytes-like object or a number, not 'list'
str
　　str(a)  # ['1', '2', '3']
dict
　　dict(a)  # ValueError: dictionary update sequence element #0 has length 1; 2 is required
tuple
　　tuple(a)  # ('1', '2', '3')
set
　　set(a)  # {'3', '2', '1'}

运算

int
    a = ['1','2','3']
    b = 2
    print(a + b)  # TypeError: can only concatenate list (not "int") to list
    print(a - b)  # TypeError: unsupported operand type(s) for -: 'list' and 'int'
    print(a * b)  # ['1', '2', '3', '1', '2', '3']
    print(a / b)  # TypeError: unsupported operand type(s) for /: 'list' and 'int'

str
    a = ['1','2','3']
    b = 'dasd'
    print(a + b)  # TypeError: can only concatenate list (not "str") to list
    print(a - b)  # TypeError: unsupported operand type(s) for -: 'list' and 'str'
    print(a * b)  # TypeError: can't multiply sequence by non-int of type 'str'
    print(a / b)  # TypeError: unsupported operand type(s) for /: 'list' and 'str'

list
    a = ['1','2','3']
    b = ['4','5','6']
    print(a + b)  # ['1', '2', '3', '4', '5', '6']
    print(a - b)  # TypeError: unsupported operand type(s) for -: 'list' and 'list'
    print(a * b)  # TypeError: can't multiply sequence by non-int of type 'list'
    print(a / b)  # TypeError: unsupported operand type(s) for /: 'list' and 'list'

dict
    a = ['1','2','3']
    b = {'a':4,'c':5}
    print(a + b)  # TypeError: can only concatenate list (not "dict") to list
    print(a - b)  # TypeError: unsupported operand type(s) for -: 'list' and 'dict'
    print(a * b)  # TypeError: can't multiply sequence by non-int of type 'dict'
    print(a / b)  # TypeError: unsupported operand type(s) for /: 'list' and 'dict'

tuple
    a = ['1','2','3']
    b = ('4','5','6')
    print(a + b)  # TypeError: can only concatenate list (not "tuple") to list
    print(a - b)  # TypeError: unsupported operand type(s) for -: 'list' and 'tuple'
    print(a * b)  # TypeError: can't multiply sequence by non-int of type 'tuple'
    print(a / b)  # TypeError: unsupported operand type(s) for /: 'list' and 'tuple'

set
    a = ['1','2','3']
    b = {'4','5','6'}
    print(a + b)  # TypeError: can only concatenate list (not "set") to list
    print(a - b)  # TypeError: unsupported operand type(s) for -: 'list' and 'set'
    print(a * b)  # TypeError: can't multiply sequence by non-int of type 'set'
    print(a / b)  # TypeError: unsupported operand type(s) for /: 'list' and 'set'

 

字典dict