if、elif、else

Python 中级

Hugo Bowne-Anderson

Data Scientist at DataCamp

概览

比较运算符
- <、>、>=、<=、==、!=
布尔运算符
- and、or、not
条件语句
- if、else、elif

if

if condition :
    expression

control.py

z = 4

if z % 2 == 0 :    # True
    print("z is even")

z is even

if

if condition :
    expression

expression 不属于 if 语句块

control.py

z = 4
if z % 2 == 0 :    # True
    print("z is even")

z is even

if

if condition :
    expression

control.py

z = 4
if z % 2 == 0 :
    print("checking "  + str(z))
    print("z is even")

checking 4
z is even

if

if condition :
    expression

control.py

z = 5
if z % 2 == 0 :    # False
    print("checking "  + str(z))
    print("z is even")

else

if condition :
    expression
else :
    expression

control.py

z = 5
if z % 2 == 0 :    # False
    print("z is even")
else :
    print("z is odd")

z is odd

elif

if condition :
    expression
elif condition :
    expression
else :
    expression

control.py

z = 3
if z % 2 == 0 :
    print("z is divisible by 2")    # False
elif z % 3 == 0 :
    print("z is divisible by 3")    # True
else :
    print("z is neither divisible by 2 nor by 3")

z is divisible by 3

elif

if condition :
    expression
elif condition :
    expression
else :
    expression

control.py

z = 6
if z % 2 == 0 :
    print("z is divisible by 2")    # True
elif z % 3 == 0 :
    print("z is divisible by 3")    # Never reached
else :
    print("z is neither divisible by 2 nor by 3")

z is divisible by 2

Ayo berlatih!

Python 中级