小白必看的python中的Bool运算和真假值

在python中，任何对象都可以判断其真假值：True，False

在if或while条件判断中，下面的情况值为False：

1.None

2.Flase

3.数值为0的情况，如：0,0.0,0j

4.所有空序列，如：'',(),[]

5.所有空mapping，如：{}

6.instances of user-defined classes, if the class defines a __bool__() or __len__() method,

when that method returns the integer zero or bool value False.

All other values are considered true — so objects of many types are always true.

在运算操作和内建函数返回Boolean结果0或者Flase表示false(更多学习内容，请点击Python学习网)

1或True表示true

python中的Boolean运算如下：

print('x or y -> if x is false,then y, else x ')
x, y= 2,0
print('{} or {} = {}'.format(x, y, xor y))
x1, y1= 0,10
print('{} or {} = {}'.format(x1, y1, x1or y1))
x2, y2= 0,0
print('{} or {} = {}'.format(x2, y2, x2or y2))
  
print('#' * 50)
print('x and y -> if x is false,then x, else y ')
print('{} and {} = {}'.format(x, y, xand y))
x1, y1= 0,10
print('{} and {} = {}'.format(x1, y1, x1and y1))
x2, y2= 0,0
print('{} and {} = {}'.format(x2, y2, x2and y2))
  
print('#' * 50)
print('not x -> if x is false,then True,else False ')
x= 2
print('not {} = {}'.format(x,not x))
x= 0
print('not {} = {}'.format(x,not x))

运行结果：

>>>
x or y -> if x is false,then y, else x
or 0 = 2
or 10 = 10
or 0 = 0
##################################################
x and y -> if x is false,then x, else y
and 0 = 0
and 10 = 0
and 0 = 0
##################################################
not x -> if x is false,then True,else False
not 2 = False
not 0 = True
>>>