Python: for, while, Loops

By Xah Lee. Date: . Last updated: .

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

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