Boolean operations and true and false values

In python, any object can determine its true or false value: True, False

In the if or while conditional judgment, the following situation value is False:

1.None

2.Flase

3. When the value is 0, such as: 0,0.0,0j

4. All empty sequences, such as: '', (), []

5. All empty mappings, such as: {}

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.

In operation operations and built-in functions, the Boolean result is returned 0 or False means false

1 or True means true

Boolean operations in python are as follows:

print('x or y -> if x is false,then y, else x ')
x, y = 2, 0
print('{} or {} = {}'.format(x, y, x or y))
x1, y1 = 0, 10
print('{} or {} = {}'.format(x1, y1, x1 or y1))
x2, y2 = 0, 0
print('{} or {} = {}'.format(x2, y2, x2 or y2))
  
print('#' * 50)
print('x and y -> if x is false,then x, else y ')
print('{} and {} = {}'.format(x, y, x and y))
x1, y1 = 0, 10
print('{} and {} = {}'.format(x1, y1, x1 and y1))
x2, y2 = 0, 0
print('{} and {} = {}'.format(x2, y2, x2 and 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))

​

Run result:

>>>>

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

>>>