Control Flow

Conditional Statements

if

name = 'Arthur'
if name == 'Arthur':
    print("I didn't know we 'ad a king!")

NOTE

• Indentation creates a block

• A colon, :, is required at the beginning of a block

• Use 4 spaces per indentation level (from the official style guide)

elif

name = 'Galahad
if name == 'Arthur':
    print("I didn't know we 'ad a king!")
elif name == 'Galahad':
    print("Sir Galahad! You would not be so ungallant as to refuse our hospitality.")

else

name = 'Galahad
if name == 'Arthur':
    print("I didn't know we 'ad a king!")
elif name == 'Galahad':
    print("Sir Galahad! You would not be so ungallant as to refuse our hospitality.")
else:
    print("Who are you?")

Loops

while loop

i = 0
while i < 11:
    print('Loop #', i)
    i += 1

for loop

for char in 'spam':
    print(char)

range range(start, stop, step)

The range function returns a sequence of numbers that starts from start (0 by default) and stops before stop, in increments of step (1 by default).

for i in range(11):
    print('Loop #', i)

for i in range(1, 11):
    print('Loop #', i)

for i in range(10, 101, 10):
    print('Loop #', i)

break & continue You can stop a loop with break or skip to the next iteration with continue

for i in range(100):
    if i % 2 != 0:
        print('odd number')
        continue
    elif i == 42:
        print('Stop at 42')
        break
    else:
        print(i)