How to Efficiently Find the First Matching Item in an Iterable?

Get the First Item from an Iterable That Matches a Condition

To retrieve the first element matching a specified condition from an iterable, avoid processing the entire iterable, which could be extensive. You can employ the following Python functions:

Python 2.6 and Python 3:

• next(x for x in the_iterable if condition): Raises StopIteration if no match is found.
• next((x for x in the_iterable if condition), default_value): Returns default_value (e.g., None) if no match is found.

Python

• use the .next() method of iterable: Raises StopIteration if iterable has no matching items.
• wrap the iterable in a function: Return the first match found, or raise StopIteration if no match is found. Implement this with itertools, for loops, generators, or try/except blocks.

Example Uses:

iterable = range(10)

# Get the first element greater than 3
first_match_gt_3 = next(x for x in iterable if condition)  # Python 2.6+

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