Python: for, while, Loops

For Loop

# python 3

# creates a list, 1 to 3
aa = range(1, 4)

for xx in aa:
    print(xx)

• range(n) → return a list from 0 to n, not including n
• range(a,b) → return a list from a to b, not including b
• range(a,b,step) → return a list from a to b, not including b, in steps of step

While Loop

# python 3

x = 1
while x <= 5:
    print(x)
    x += 1

Exit Loop

Use break or continue to exit loop.

• break → exit the loop.
• continue → skip rest of loop code and start the next iteration.

# python 3

for x in range(1, 10):
    print(x)
    if x == 4:
        break
# prints 1 to 4

See also:

• Python: Loop Thru List
• Python: Loop Thru Dictionary