group-by

Pandas: Per-group min start and max end across numbered columns via wide_to_long or row-wise

Dec. 7, 17:00

Pandas groupby with a Series: how index alignment affects groups and why reset_index shifts groups

Oct. 21, 05:00

Pandas lexicographic group sorting: aggregate to tuples, sort, and explode for tie-aware order

Sep. 30, 23:00

Pandas groupby: filter grouped data by original index, keep rows, and count surviving groups

Sep. 22, 17:00

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