Python · Theory

for Loop vs while Loop in Python

Theory

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for Loop vs while Loop in Python

for is for walking a known sequence or range: for name in names, for i in range(5). while is for “until this becomes false”: while not done, while line != "". You can fake one with the other, but readers suffer. Prefer for when you have items. Prefer while when the stop is a condition, not a list.

Best-fit examples: print each mark → for. Read input until quit → while. range belongs with for. Infinite risk belongs with while.

for Loop vs while Loop in Python — output: for Asha, for Ravi, while 2, while 1.

Diagram

i = 1
    │ i <= 3 ?
    ▼ yes
  print(i); i += 1
    │
    ▼ i = 4 → stop

Exam tip

One best-fit example for each loop.

Example

# for vs while
for x in ["Asha", "Ravi"]:
    print("for", x)
n = 2
while n > 0:
    print("while", n)
    n -= 1

for Loop vs while Loop in Python — output: for Asha, for Ravi, while 2, while 1.

Short notes

DefFor = iterate
RuleWhile = condition
RememberPick for readability

Python · Theory

for Loop vs while Loop in Python

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Theory

28/268

for Loop vs while Loop in Python

Best-fit examples: print each mark → for. Read input until quit → while. range belongs with for. Infinite risk belongs with while.

for Loop vs while Loop in Python — output: for Asha, for Ravi, while 2, while 1.

Diagram

i = 1
    │ i <= 3 ?
    ▼ yes
  print(i); i += 1
    │
    ▼ i = 4 → stop

Exam tip

One best-fit example for each loop.

Example

# for vs while
for x in ["Asha", "Ravi"]:
    print("for", x)
n = 2
while n > 0:
    print("while", n)
    n -= 1

for Loop vs while Loop in Python — output: for Asha, for Ravi, while 2, while 1.

Short notes

DefFor = iterate
RuleWhile = condition
RememberPick for readability

for Loop vs while Loop in Python

Example

Short notes

Questions

for Loop vs while Loop in Python

Example

Short notes

Questions