if, elif, else

Python intermédiaire

Hugo Bowne-Anderson

Data Scientist at DataCamp

Vue d’ensemble

  • Opérateurs de comparaison
    • <, >, >=, <=, ==, !=
  • Opérateurs booléens
    • and, or, not
  • Déclarations conditionnelles
    • if, else, elif
Python intermédiaire

if

if condition :
    expression

control.py

z = 4

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

if

if condition :
    expression
  • expression ne fait pas partie de if

control.py

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

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
Python intermédiaire

if

if condition :
    expression

control.py

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

Python intermédiaire

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
Python intermédiaire

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
Python intermédiaire

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
Python intermédiaire

Passons à la pratique !

Python intermédiaire

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