Python · Theory

Loops in Python

Theory

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Loops in Python

A loop repeats a block until you stop it. for walks each item in a list, string, or range. while repeats while a condition stays true. Pick for when you know the items. Pick while when you wait until something becomes false — like “until the user types quit”.

break leaves the loop. continue skips the rest of this round. pass does nothing. while True without a break or an update never ends — the terminal just sits there. That infinite-loop trap is worth one sentence in the viva.

Loops in Python — output — for 1 2 3 then while 3 2 1.

Exam tip

Define loop, then for vs while in one line each.

Example

# Loops
for i in range(1, 4):
    print("for", i)
n = 3
while n > 0:
    print("while", n)
    n -= 1

Loops in Python — output: for 1 2 3 then while 3 2 1.

Short notes

DefRepeat a block.
Rulefor = items. while = condition.
TrapInfinite while True.

Python · Theory

Loops in Python

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Theory

21/268

Loops in Python

Loops in Python — output — for 1 2 3 then while 3 2 1.

Exam tip

Define loop, then for vs while in one line each.

Example

# Loops
for i in range(1, 4):
    print("for", i)
n = 3
while n > 0:
    print("while", n)
    n -= 1

Loops in Python — output: for 1 2 3 then while 3 2 1.

Short notes

DefRepeat a block.
Rulefor = items. while = condition.
TrapInfinite while True.

Loops in Python

Example

Short notes

Questions

Loops in Python

Example

Short notes

Questions