How to find the maximum value of each group after groupby () grouping operation

This article mainly shows you "how to find the maximum value of each group after the grouping operation through groupby ()". The content is simple and clear. I hope it can help you solve your doubts. Let me lead you to study and learn how to find the maximum value of each group after grouping operation through groupby ().

Load the data source:

Import pandas as pd df3 = pd.read_excel (r "D:\ my documents\ jupyter.xlsx", sheet_name = 1) df3

1. Method one

Df4 = df3.groupby ("city"). Apply (lambda x: X [x. Sales quantity = = x. Sales quantity .max ()) df4

two。 Method two

Df3.groupby (["city"]) ["sales quantity"] .agg (max) idx = df3.groupby (["city"]) ["sales quantity"] .transform (max) idxidx1 = idx = = df3 ["sales quantity"] idx1 df3 [idx1]

3. Method three

Df3.sort_values (by = "sales quantity", ascending = False) .groupby ("city", as_index=False) .first ()

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