[Python] Pivot Table (피벗테이블)

[Python] Pivot Table (피벗테이블)

• groupby 집계의 다차원 버전이다.

import numpy as np
import pandas as pd
import seaborn as sns
titanic = sns.load_dataset('titanic')

survived

pclass

sex

age

sibsp

parch

fare

embarked

class

who

adult_male

deck

embark_town

alive

alone

0

0

3

male

22

1

0

7.25

S

Third

man

TRUE

Southampton

no

FALSE

1

1

1

female

38

1

0

71.2833

C

First

woman

FALSE

C

Cherbourg

yes

FALSE

2

1

3

female

26

0

0

7.925

S

Third

woman

FALSE

Southampton

yes

TRUE

3

1

1

female

35

1

0

53.1

S

First

woman

FALSE

C

Southampton

yes

FALSE

4

0

3

male

35

0

0

8.05

S

Third

man

TRUE

Southampton

no

TRUE

성별과 자석 등급별 생존율

groupby

titanic.groupby(['sex','class'])['survived'].aggregate('mean').unstack()

• unstack()

type(titanic.groupby(['sex','class'])['survived'].aggregate('mean').unstack())

-> pandas.core.frame.DataFrame

 

no_stack = titanic.groupby(['sex','class'])['survived'].mean()
no_stack

• unstack()함수를 호출하지 않으면 index기준 위->아래로 재구조화된다.
• type(no_stack) => series

nostack.loc['male'].loc['Second']

pivot

titanic.pivot_table('survived',index='sex',columns='class')

• 데이터를 보면 1등석에 탄 여성은 거의 생존했지만 3등석에 탄 남성은 거의 생존하지 못했다.