# list: list Comprehension

## list Comprehension

>>> squares = [x**2 for x in range(10)]
>>> squares
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
• Provide a concise way to create lists.
• Consists of brackets containing an expression followed by a for clause, then zero or more for or if clauses.
• Result will be a new list resulting from evaluating the expression in the context of the for and if clauses which follow it.
• >>> combs = [(x, y) for x in [1,2,3] for y in [3,1,4] if x != y] >>> combs [(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)] # same as >>> combs = [] >>> for x in [1,2,3]: ... for y in [3,1,4]: ... if x != y: ... combs.append((x, y)) ... >>> combs [(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)].

## Related concepts

list Comprehension

## list: list Comprehension — Structure map

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