Control Structures

if, elif, else

n = 1
if (n > 0):
    print('n > 0')
elif (n == 0):
    print('n == 0')
else:
    print('n < 0')

Output:

n > 0

for

numbers = (1, 2, 3, 4, 5, 6, 7, 8, 9)
for n in numbers:
    if n == 2:
        continue
    elif n == 5:
        break
    else:
        pass
print(n)

Output:

5

while

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9]
while len(numbers) > 1:
    print(numbers.pop(), end=',')
print(' ... and the last number is ' + str(numbers[0]))

Output:

9,8,7,6,5,4,3,2, ... and the last number is 1
# while-else
numbers=[1,2,3,4,5,6,7,8,9]
while len(numbers) > 1:
    print(numbers.pop(), end=", ")
else:
    print(numbers[0])

Output:

9, 8, 7, 6, 5, 4, 3, 2, 1
[1]
# while-else with a break statement
numbers=[1,2,3,4,5,6,7,8,9]
while len(numbers) > 1:
    print(numbers.pop(), end=', ')    
    if len(numbers) == 5:
        break
else:
    print('else')
print(numbers)    

Output:

9, 8, 7, 6, [1, 2, 3, 4, 5]

References