Tabele przestawne
Manipulacja danymi z pandas
Maggie Matsui
Senior Content Developer at DataCamp
Od grupowania do tabeli przestawnej
dogs.groupby("color")["weight_kg"].mean()
color
Black 26
Brown 24
Gray 17
Tan 2
White 74
Name: weight_kg, dtype: int64
dogs.pivot_table(values="weight_kg",
index="color")
weight_kg
color
Black 26.5
Brown 24.0
Gray 17.0
Tan 2.0
White 74.0
Różne statystyki
dogs.pivot_table(values="weight_kg", index="color", aggfunc="median")
weight_kg
color
Black 26.5
Brown 24.0
Gray 17.0
Tan 2.0
White 74.0
Wiele statystyk
dogs.pivot_table(values="weight_kg", index="color", aggfunc=["mean", "median"])
mean median
weight_kg weight_kg
color
Black 26.5 26.5
Brown 24.0 24.0
Gray 17.0 17.0
Tan 2.0 2.0
White 74.0 74.0
Tabela przestawna na dwóch zmiennych
dogs.groupby(["color", "breed"])["weight_kg"].mean()
dogs.pivot_table(values="weight_kg", index="color", columns="breed")
breed Chihuahua Chow Chow Labrador Poodle Schnauzer St. Bernard
color
Black NaN NaN 29.0 24.0 NaN NaN
Brown NaN 24.0 24.0 NaN NaN NaN
Gray NaN NaN NaN NaN 17.0 NaN
Tan 2.0 NaN NaN NaN NaN NaN
White NaN NaN NaN NaN NaN 74.0
Uzupełnianie brakujących wartości w tabelach przestawnych
dogs.pivot_table(values="weight_kg", index="color", columns="breed", fill_value=0)
breed Chihuahua Chow Chow Labrador Poodle Schnauzer St. Bernard
color
Black 0 0 29 24 0 0
Brown 0 24 24 0 0 0
Gray 0 0 0 0 17 0
Tan 2 0 0 0 0 0
White 0 0 0 0 0 74
Sumowanie w tabelach przestawnych
dogs.pivot_table(values="weight_kg", index="color", columns="breed",
fill_value=0, margins=True)
breed Chihuahua Chow Chow Labrador Poodle Schnauzer St. Bernard All
color
Black 0 0 29 24 0 0 26.500000
Brown 0 24 24 0 0 0 24.000000
Gray 0 0 0 0 17 0 17.000000
Tan 2 0 0 0 0 0 2.000000
White 0 0 0 0 0 74 74.000000
All 2 24 26 24 17 74 27.714286
Ćwiczmy!
Manipulacja danymi z pandas
