Transpose a matrix in Python

Rows become columns in one idiom.

def transpose(matrix):
    if not matrix:
        return []
    return [list(row) for row in zip(*matrix)]

How it works

1. zip(*matrix) unpacks the rows as separate arguments.
2. zip regroups them element-by-element into columns.
3. Each column tuple becomes a list.

Keywords and builtins used here

• def
• for
• if
• list
• return
• transpose
• zip

The run, in numbers

Lines

4

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90

Tokens

28

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95 tpm

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Type this snippet

Step 7 of 10 in Collections, step 29 of 72 in Language basics.

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