Reference library

Lists & loops

Iterate, transform, and combine sequences with readable loop patterns.

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Lists & loops easy

How to unzip a list of pairs into two lists in Python

Split a list of (a, b) tuples into two separate lists by iterating with a for loop and appending each element to its own output list.

lists tuples loops
Python 
def unzip(pairs):
    """Split a list of (a, b) pairs into two separate lists."""
    if not pairs:
        return [], []
    
    firsts = []
    seconds = []
    for a, b in pairs:
        firsts.append(a)
        seconds.append(b)
    
    return firsts, seconds


if __name__ == "__main__":
    pairs = [(1, 'a'), (…
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