Repeated execution of a statement until a condition becomes false (loop until condition changes).

Expresses repetition until a condition becomes true; conveys ongoing activity until a goal is reached.

Used when an action must be repeated until a certain state is reached, such as polling for completion, waiting for user input, or processing items until a queue is empty.

Polling loops, game loops, waiting for external events, processing batches until empty.

while not <condition>: <statement>

while not <condition>: <statement>

<condition>: boolean expression; <statement>: statement or block to repeat.

• finished
• done
• ready
• exit
• flag
• done_flag

• condition variable (e.g.
• not done
• not ready
• not exit)
• action statement (e.g.
• do_work()
• process_item()
• read_input())

Failing to update the condition inside the loop causing infinite loop; using assignment (=) instead of comparison (==) in condition; incorrect indentation; confusing 'while not' with 'while' (inverted logic).

while finished: (loop while true), while True: with break when condition met, until loop (in some languages) which repeats until condition true.

Confusing 'while not' with 'while' (negation confusion); accidental infinite loops if condition never changes.

• while-loop patterns

Expresses a busy-wait or polling loop; assumes condition will eventually become true; may consume CPU unless combined with sleep or delay.

Communicates persistent effort until a goal is achieved; conveys expectation of eventual termination.

Keep working until finished.

Common polling idiom; ensure the condition is updated inside the loop to avoid infinite spinning.

Consider using event‑driven callbacks or async/await instead of busy‑wait loops for better efficiency.