pandas之透视表和交叉表

import pandas as pd
import warnings

warnings.filterwarnings('ignore')

# 读取用户表
users = pd.read_table('./users.dat', header=None, names=['UserID', 'Gender', 'Age', 'Occupation', 'Zip-code'], sep='::',
                      engine='python')
# print(users.head())
# 读取评分表
ratings = pd.read_table('./ratings.dat', header=None, names=['UserID', 'MovieID', 'Rating', 'Timestamp'], sep='::',
                        engine='python')
# print(ratings.head())
# 读取电影详情表
movies = pd.read_table('./movies.dat', header=None, names=['MovieID', 'Title', 'Genres'], sep='::', engine='python')
# print(movies.head())
# 将表进行合并
data = pd.merge(pd.merge(ratings, users), movies)
print(data.head())

# 使用pivot_table方法查看，每一部电影不同性别的平均评分
data_gender = pd.pivot_table(data, index='Title', columns='Gender', values='Rating', margins=True)
# data_gender = data.pivot_table(index='Title', columns='Gender', values='Rating')
print(data_gender.head())

# 使用groupby方法
data_gender = data.groupby(['Title', 'Gender']).agg({'Rating': 'mean'})
print(data_gender.head())

# 使用crosstab方法查看每一部电影不同性别的平均评分
data_gender = pd.crosstab(data.Title, data.Gender, data.Rating, aggfunc='mean')
print(data_gender.head())


输出结果：
   UserID  MovieID  ...                                   Title  Genres
0       1     1193  ...  One Flew Over the Cuckoo's Nest (1975)   Drama
1       2     1193  ...  One Flew Over the Cuckoo's Nest (1975)   Drama
2      12     1193  ...  One Flew Over the Cuckoo's Nest (1975)   Drama
3      15     1193  ...  One Flew Over the Cuckoo's Nest (1975)   Drama
4      17     1193  ...  One Flew Over the Cuckoo's Nest (1975)   Drama

[5 rows x 10 columns]
Gender                                F         M       All
Title                                                      
$1,000,000 Duck (1971)         3.375000  2.761905  3.027027
'Night Mother (1986)           3.388889  3.352941  3.371429
'Til There Was You (1997)      2.675676  2.733333  2.692308
'burbs, The (1989)             2.793478  2.962085  2.910891
...And Justice for All (1979)  3.828571  3.689024  3.713568
                                    Rating
Title                     Gender          
$1,000,000 Duck (1971)    F       3.375000
                          M       2.761905
'Night Mother (1986)      F       3.388889
                          M       3.352941
'Til There Was You (1997) F       2.675676
Gender                                F         M
Title                                            
$1,000,000 Duck (1971)         3.375000  2.761905
'Night Mother (1986)           3.388889  3.352941
'Til There Was You (1997)      2.675676  2.733333
'burbs, The (1989)             2.793478  2.962085
...And Justice for All (1979)  3.828571  3.689024

import pandas as pd

data = pd.DataFrame({'Sample': range(1, 11),
                     'Gender': ['Female', 'Male', 'Female', 'Male', 'Male', 'Male', 'Female', 'Female', 'Male',
                                'Female'],
                     'Handedness': ['Right-handed', 'Left-handed', 'Right-handed', 'Right-handed', 'Left-handed',
                                    'Right-handed', 'Right-handed', 'Left-handed', 'Right-handed', 'Right-handed']})
print(data)

# 方法1 ：使用pivot_table
data1 = pd.pivot_table(data, index='Gender', columns='Handedness', aggfunc=len, margins=True)
print(data1)

# 方法2：使用crosstab
data2 = pd.crosstab(data.Gender, data.Handedness, data.Sample, aggfunc=len, margins=True)
print(data2)

输出结果：
   Sample  Gender    Handedness
0       1  Female  Right-handed
1       2    Male   Left-handed
2       3  Female  Right-handed
3       4    Male  Right-handed
4       5    Male   Left-handed
5       6    Male  Right-handed
6       7  Female  Right-handed
7       8  Female   Left-handed
8       9    Male  Right-handed
9      10  Female  Right-handed
                Sample                 
Handedness Left-handed Right-handed All
Gender                                 
Female               1            4   5
Male                 2            3   5
All                  3            7  10
Handedness  Left-handed  Right-handed  All
Gender                                    
Female                1             4    5
Male                  2             3    5
All                   3             7   10