merge 메서드 사용¶

연결 전용 메서드¶

In [1]:

import pandas as pd

In [2]:

person = pd.read_csv('../../data/survey_person.csv')   # 관측한 사람
site = pd.read_csv('../../data/survey_site.csv')   # 관측 위치
survey = pd.read_csv('../../data/survey_survey.csv')   # 관측 날짜
visited = pd.read_csv('../../data/survey_visited.csv')   # 날씨 정보
person

Out[2]:

	ident	personal	family
0	dyer	William	Dyer
1	pb	Frank	Pabodie
2	lake	Anderson	Lake
3	roe	Valentina	Roerich
4	danforth	Frank	Danforth

In [3]:

survey

Out[3]:

	taken	person	quant	reading
0	619	dyer	rad	9.82
1	619	dyer	sal	0.13
2	622	dyer	rad	7.80
3	622	dyer	sal	0.09
4	734	pb	rad	8.41
5	734	lake	sal	0.05
6	734	pb	temp	-21.50
7	735	pb	rad	7.22
8	735	NaN	sal	0.06
9	735	NaN	temp	-26.00
10	751	pb	rad	4.35
11	751	pb	temp	-18.50
12	751	lake	sal	0.10
13	752	lake	rad	2.19
14	752	lake	sal	0.09
15	752	lake	temp	-16.00
16	752	roe	sal	41.60
17	837	lake	rad	1.46
18	837	lake	sal	0.21
19	837	roe	sal	22.50
20	844	roe	rad	11.25

In [4]:

site

Out[4]:

	name	lat	long
0	DR-1	-49.85	-128.57
1	DR-3	-47.15	-126.72
2	MSK-4	-48.87	-123.40

In [5]:

visited

Out[5]:

	ident	site	dated
0	619	DR-1	1927-02-08
1	622	DR-1	1927-02-10
2	734	DR-3	1939-01-07
3	735	DR-3	1930-01-12
4	751	DR-3	1930-02-26
5	752	DR-3	NaN
6	837	MSK-4	1932-01-14
7	844	DR-1	1932-03-22

In [6]:

# 0,2,6 번째 행의 데이터
visited_subset = visited.loc[[0,2,6], ]
print(visited_subset)
print(site)

   ident   site       dated
0    619   DR-1  1927-02-08
2    734   DR-3  1939-01-07
6    837  MSK-4  1932-01-14
    name    lat    long
0   DR-1 -49.85 -128.57
1   DR-3 -47.15 -126.72
2  MSK-4 -48.87 -123.40

In [7]:

# merge : 기본적으로 내부 조인을 실행하며 메서드를 사용한
# 데이터 프레임(site)을 왼쪽으로 지정, 첫 번째 인자값으로
# 지정한 데이터 프레임(visited_subset)을 오른쪽으로 지정
# 열 이름 일치 - 왼쪽 프레임을 기준으로 연결

o2o_merge = site.merge(visited_subset, left_on='name', \
                      right_on='site')
print(o2o_merge)

    name    lat    long  ident   site       dated
0   DR-1 -49.85 -128.57    619   DR-1  1927-02-08
1   DR-3 -47.15 -126.72    734   DR-3  1939-01-07
2  MSK-4 -48.87 -123.40    837  MSK-4  1932-01-14

In [8]:

m2o_merge = site.merge(visited, left_on='name', right_on='site')
print(m2o_merge)

    name    lat    long  ident   site       dated
0   DR-1 -49.85 -128.57    619   DR-1  1927-02-08
1   DR-1 -49.85 -128.57    622   DR-1  1927-02-10
2   DR-1 -49.85 -128.57    844   DR-1  1932-03-22
3   DR-3 -47.15 -126.72    734   DR-3  1939-01-07
4   DR-3 -47.15 -126.72    735   DR-3  1930-01-12
5   DR-3 -47.15 -126.72    751   DR-3  1930-02-26
6   DR-3 -47.15 -126.72    752   DR-3         NaN
7  MSK-4 -48.87 -123.40    837  MSK-4  1932-01-14

In [9]:

ps = person.merge(survey, left_on='ident', right_on='person')
vs = visited.merge(survey, left_on='ident', right_on='taken')
ps

Out[9]:

	ident	personal	family	taken	person	quant	reading
0	dyer	William	Dyer	619	dyer	rad	9.82
1	dyer	William	Dyer	619	dyer	sal	0.13
2	dyer	William	Dyer	622	dyer	rad	7.80
3	dyer	William	Dyer	622	dyer	sal	0.09
4	pb	Frank	Pabodie	734	pb	rad	8.41
5	pb	Frank	Pabodie	734	pb	temp	-21.50
6	pb	Frank	Pabodie	735	pb	rad	7.22
7	pb	Frank	Pabodie	751	pb	rad	4.35
8	pb	Frank	Pabodie	751	pb	temp	-18.50
9	lake	Anderson	Lake	734	lake	sal	0.05
10	lake	Anderson	Lake	751	lake	sal	0.10
11	lake	Anderson	Lake	752	lake	rad	2.19
12	lake	Anderson	Lake	752	lake	sal	0.09
13	lake	Anderson	Lake	752	lake	temp	-16.00
14	lake	Anderson	Lake	837	lake	rad	1.46
15	lake	Anderson	Lake	837	lake	sal	0.21
16	roe	Valentina	Roerich	752	roe	sal	41.60
17	roe	Valentina	Roerich	837	roe	sal	22.50
18	roe	Valentina	Roerich	844	roe	rad	11.25

In [10]:

vs

Out[10]:

	ident	site	dated	taken	person	quant	reading
0	619	DR-1	1927-02-08	619	dyer	rad	9.82
1	619	DR-1	1927-02-08	619	dyer	sal	0.13
2	622	DR-1	1927-02-10	622	dyer	rad	7.80
3	622	DR-1	1927-02-10	622	dyer	sal	0.09
4	734	DR-3	1939-01-07	734	pb	rad	8.41
5	734	DR-3	1939-01-07	734	lake	sal	0.05
6	734	DR-3	1939-01-07	734	pb	temp	-21.50
7	735	DR-3	1930-01-12	735	pb	rad	7.22
8	735	DR-3	1930-01-12	735	NaN	sal	0.06
9	735	DR-3	1930-01-12	735	NaN	temp	-26.00
10	751	DR-3	1930-02-26	751	pb	rad	4.35
11	751	DR-3	1930-02-26	751	pb	temp	-18.50
12	751	DR-3	1930-02-26	751	lake	sal	0.10
13	752	DR-3	NaN	752	lake	rad	2.19
14	752	DR-3	NaN	752	lake	sal	0.09
15	752	DR-3	NaN	752	lake	temp	-16.00
16	752	DR-3	NaN	752	roe	sal	41.60
17	837	MSK-4	1932-01-14	837	lake	rad	1.46
18	837	MSK-4	1932-01-14	837	lake	sal	0.21
19	837	MSK-4	1932-01-14	837	roe	sal	22.50
20	844	DR-1	1932-03-22	844	roe	rad	11.25

In [11]:

# ps 데이터 프레임의 ident, taken, quant, reading 열의 값과 vs 데이터
ps_vs = ps.merge(vs, left_on = \
                 ['ident', 'taken','quant', 'reading'],
                 right_on =['person', 'ident', 'quant', 'reading'])
ps_vs
# 중복된 열 이름(ident, taken, person)에 접미사 _x(왼쪽), _y(오른쪽)가 추가됨

Out[11]:

	ident_x	personal	family	taken_x	person_x	quant	reading	ident_y	site	dated	taken_y	person_y
0	dyer	William	Dyer	619	dyer	rad	9.82	619	DR-1	1927-02-08	619	dyer
1	dyer	William	Dyer	619	dyer	sal	0.13	619	DR-1	1927-02-08	619	dyer
2	dyer	William	Dyer	622	dyer	rad	7.80	622	DR-1	1927-02-10	622	dyer
3	dyer	William	Dyer	622	dyer	sal	0.09	622	DR-1	1927-02-10	622	dyer
4	pb	Frank	Pabodie	734	pb	rad	8.41	734	DR-3	1939-01-07	734	pb
5	pb	Frank	Pabodie	734	pb	temp	-21.50	734	DR-3	1939-01-07	734	pb
6	pb	Frank	Pabodie	735	pb	rad	7.22	735	DR-3	1930-01-12	735	pb
7	pb	Frank	Pabodie	751	pb	rad	4.35	751	DR-3	1930-02-26	751	pb
8	pb	Frank	Pabodie	751	pb	temp	-18.50	751	DR-3	1930-02-26	751	pb
9	lake	Anderson	Lake	734	lake	sal	0.05	734	DR-3	1939-01-07	734	lake
10	lake	Anderson	Lake	751	lake	sal	0.10	751	DR-3	1930-02-26	751	lake
11	lake	Anderson	Lake	752	lake	rad	2.19	752	DR-3	NaN	752	lake
12	lake	Anderson	Lake	752	lake	sal	0.09	752	DR-3	NaN	752	lake
13	lake	Anderson	Lake	752	lake	temp	-16.00	752	DR-3	NaN	752	lake
14	lake	Anderson	Lake	837	lake	rad	1.46	837	MSK-4	1932-01-14	837	lake
15	lake	Anderson	Lake	837	lake	sal	0.21	837	MSK-4	1932-01-14	837	lake
16	roe	Valentina	Roerich	752	roe	sal	41.60	752	DR-3	NaN	752	roe
17	roe	Valentina	Roerich	837	roe	sal	22.50	837	MSK-4	1932-01-14	837	roe
18	roe	Valentina	Roerich	844	roe	rad	11.25	844	DR-1	1932-03-22	844	roe

[23.06.15] Python merge - 10(2)

merge 메서드 사용¶

연결 전용 메서드¶