city = college_data["CITY"]print(city)print("<"+"="*75+">")print("类型为:",type(city))
INSTNM
Alabama A & M University Normal
University of Alabama at Birmingham Birmingham
Amridge University Montgomery
University of Alabama in Huntsville Huntsville
...
Rasmussen College - Overland Park Overland Park
National Personal Training Institute of Cleveland Highland Heights
Bay Area Medical Academy - San Jose Satellite Location San Jose
Excel Learning Center-San Antonio South San Antonio
Name: CITY, Length: 7535, dtype: object
<===========================================================================>
类型为: <class 'pandas.core.series.Series'>
INSTNM
Alabama A & M University Normal
University of Alabama at Birmingham Birmingham
Amridge University Montgomery
University of Alabama in Huntsville Huntsville
Name: CITY, dtype: object
14.1.2.3 分片获取
# 获取整数索引 [0,10) 步长为2,这样选出的依然为Series
city[0:10:2]
INSTNM
Alabama A & M University Normal
Amridge University Montgomery
Alabama State University Montgomery
Central Alabama Community College Alexander City
Auburn University at Montgomery Montgomery
Name: CITY, dtype: object
14.1.3 loc 用法
传入索引标签选取一个
city["Alabama A & M University"]
'Normal'
14.1.3.1 通过标签列表选取多行
# 这样通过传入的标签索引列表选取多行,返回的依然是Series
city[["Alabama A & M University","Amridge University"]]
INSTNM
Alabama A & M University Normal
Amridge University Montgomery
Name: CITY, dtype: object
14.1.3.2 分片选取
# 选取标签索引 [start_target,end_target] 步长为1的行,返回的是Series,注意这里是端点值都能取到
city["Alabama A & M University":"University of Alabama in Huntsville":1]
INSTNM
Alabama A & M University Normal
University of Alabama at Birmingham Birmingham
Amridge University Montgomery
University of Alabama in Huntsville Huntsville
Name: CITY, dtype: object
14.2 选取DataFrame的行
14.2.1 iloc用法
14.2.1.1 传入一个整数索引值获取一行数据(返回类型为Series)
college_data.iloc[0]
CITY Normal
STABBR AL
HBCU 1
MENONLY 0
...
PCTFLOAN 0.8284
UG25ABV 0.1049
MD_EARN_WNE_P10 30300
GRAD_DEBT_MDN_SUPP 33888
Name: Alabama A & M University, Length: 26, dtype: object
# 获取标签索引对应的数据行,返回类型为Series
college_data.loc["University of Alabama at Birmingham"]
CITY Birmingham
STABBR AL
HBCU 0
MENONLY 0
...
PCTFLOAN 0.5214
UG25ABV 0.2422
MD_EARN_WNE_P10 39700
GRAD_DEBT_MDN_SUPP 21941.5
Name: University of Alabama at Birmingham, Length: 26, dtype: object
14.2.2.2 传入一个标签列表获取多行
# 根据传入的标签列表返回相应的数据行,返回类型为DataFrame
college_data.loc[["University of Alabama at Birmingham","The University of Alabama"]]
CITY
STABBR
HBCU
MENONLY
...
PCTFLOAN
UG25ABV
MD_EARN_WNE_P10
GRAD_DEBT_MDN_SUPP
INSTNM
University of Alabama at Birmingham
Birmingham
AL
0.0
0.0
...
0.5214
0.2422
39700
21941.5
The University of Alabama
Tuscaloosa
AL
0.0
0.0
...
0.4010
0.0853
41900
23750
2 rows × 26 columns
14.2.2.3 分片获取
# 获取[start_target,end_tartget] 步长为 1 的数据行,返回为DataFrame
college_data.loc["University of Alabama at Birmingham":"University of Alabama in Huntsville":1]
CITY
STABBR
HBCU
MENONLY
...
PCTFLOAN
UG25ABV
MD_EARN_WNE_P10
GRAD_DEBT_MDN_SUPP
INSTNM
University of Alabama at Birmingham
Birmingham
AL
0.0
0.0
...
0.5214
0.2422
39700
21941.5
Amridge University
Montgomery
AL
0.0
0.0
...
0.7795
0.8540
40100
23370
University of Alabama in Huntsville
Huntsville
AL
0.0
0.0
...
0.4596
0.2640
45500
24097
3 rows × 26 columns
14.3 同时选取DataFrame的行和列
14.3.1 获取前n行m列
14.3.1.1 用 iloc 方法实现
# 获取前面两行三列数据
college_data.iloc[:2,:3]
CITY
STABBR
HBCU
INSTNM
Alabama A & M University
Normal
AL
1.0
University of Alabama at Birmingham
Birmingham
AL
0.0
14.3.1.2 用 loc方法 实现
# 获取行索引从[start_target,end_target]的行,和列索引为[start,end]的列
college_data.loc[:"University of Alabama at Birmingham",:"HBCU"]
CITY
STABBR
HBCU
INSTNM
Alabama A & M University
Normal
AL
1.0
University of Alabama at Birmingham
Birmingham
AL
0.0
14.3.2 获取全部行中的前n列
14.3.2.1 用 iloc 方法实现
college_data.iloc[:,:2]
CITY
STABBR
INSTNM
Alabama A & M University
Normal
AL
University of Alabama at Birmingham
Birmingham
AL
Amridge University
Montgomery
AL
University of Alabama in Huntsville
Huntsville
AL
...
...
...
Rasmussen College - Overland Park
Overland Park
KS
National Personal Training Institute of Cleveland
Highland Heights
OH
Bay Area Medical Academy - San Jose Satellite Location
San Jose
CA
Excel Learning Center-San Antonio South
San Antonio
TX
7535 rows × 2 columns
14.3.2.2 用 loc 方法实现
college_data.loc[:,:"STABBR"]
CITY
STABBR
INSTNM
Alabama A & M University
Normal
AL
University of Alabama at Birmingham
Birmingham
AL
Amridge University
Montgomery
AL
University of Alabama in Huntsville
Huntsville
AL
...
...
...
Rasmussen College - Overland Park
Overland Park
KS
National Personal Training Institute of Cleveland
Highland Heights
OH
Bay Area Medical Academy - San Jose Satellite Location
San Jose
CA
Excel Learning Center-San Antonio South
San Antonio
TX
7535 rows × 2 columns
14.3.3 选取不连续的行和列
14.3.3.1 用 iloc 方法实现
college_data.iloc[[1,3,5,7],[2,4,6,8]]
HBCU
WOMENONLY
SATVRMID
DISTANCEONLY
INSTNM
University of Alabama at Birmingham
0.0
0.0
570.0
0.0
University of Alabama in Huntsville
0.0
0.0
595.0
0.0
The University of Alabama
0.0
0.0
555.0
0.0
Athens State University
0.0
0.0
NaN
0.0
14.3.3.2 用 loc 方法实现
# 这里实现的需求同上
college_data.loc[["University of Alabama at Birmingham","University of Alabama in Huntsville","The University of Alabama","Athens State University"],["HBCU","WOMENONLY","SATVRMID","DISTANCEONLY"]]
HBCU
WOMENONLY
SATVRMID
DISTANCEONLY
INSTNM
University of Alabama at Birmingham
0.0
0.0
570.0
0.0
University of Alabama in Huntsville
0.0
0.0
595.0
0.0
The University of Alabama
0.0
0.0
555.0
0.0
Athens State University
0.0
0.0
NaN
0.0
14.3.4 选取某一个标量的值
14.3.4.1 用 iloc方法实现
# 选取第四行四列的值
college_data.iloc[3,3]
0.0
14.3.4.2 用 loc 方法实现
# 实现的需求同上
college_data.loc["Athens State University","MENONLY"]