if

# if.py

pwd = input('What is the password? ')

if pwd == 'apple':

print('Logging on ...')

else:

print('Incorrect password.')

 

 

运行结果：

>>>

What is the password? banana

Incorrect password.

>>>

What is the password? apple

Logging on ...

 

 

--elif

if 条件：

表达式

elif 条件：

表达式

else：

表达式

 

--条件表达式

# if1.py

food = input('What is your favorite food? ')

reply = 'Yes' if food == 'apple' else 'No'

print(reply)

 

运行结果：

>>>

What is your favorite food? apple

Yes

>>>

What is your favorite food? banana

No