Python数据转换与运算

整形 int

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}

a = 1
b = 2.1
print(a+b)
print(a-b)
print(a*b)
print(a/b)  a/0  # ZeroDivisionError: division by zero


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'


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'


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'


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