[PYTHON/PANDAS] merge 함수 : on/how 인자를 사용해 FULL JOIN 데이터 만들기

■ merge 함수에서 on/how 인자를 사용해 FULL JOIN 데이터를 만드는 방법을 보여준다.

▶ main.py


import pandas as pd
import numpy  as np

dataFrame1 = pd.DataFrame({"key" : ["A", "B", "C", "D"], "value" : np.random.randn(4)})
dataFrame2 = pd.DataFrame({"key" : ["B", "D", "D", "E"], "value" : np.random.randn(4)})

print(dataFrame1)

"""
  key     value
0   A -0.050330
1   B  0.754153
2   C  0.693311
3   D -0.543704
"""

print()

print(dataFrame2)

"""
  key     value
0   B -0.291885
1   D  0.871071
2   D  0.270238
3   E  0.509288
"""

print()

dataFrame3 = pd.merge(dataFrame1, dataFrame2, on = "key", how = "outer") # FULL JOIN

print(dataFrame3)

"""
  key   value_x   value_y
0   A -0.050330       NaN
1   B  0.754153 -0.291885
2   C  0.693311       NaN
3   D -0.543704  0.871071
4   D -0.543704  0.270238
5   E       NaN  0.509288
"""

import pandas as pd

import numpy as np

dataFrame1 = pd.DataFrame({"key" : ["A", "B", "C", "D"], "value" : np.random.randn(4)})

dataFrame2 = pd.DataFrame({"key" : ["B", "D", "D", "E"], "value" : np.random.randn(4)})

print(dataFrame1)

"""

key value

0 A -0.050330

1 B 0.754153

2 C 0.693311

3 D -0.543704

"""

print()

print(dataFrame2)

"""

key value

0 B -0.291885

1 D 0.871071

2 D 0.270238

3 E 0.509288

"""

print()

dataFrame3 = pd.merge(dataFrame1, dataFrame2, on = "key", how = "outer") # FULL JOIN

print(dataFrame3)

"""

key value_x value_y

0 A -0.050330 NaN

1 B 0.754153 -0.291885

2 C 0.693311 NaN

3 D -0.543704 0.871071

4 D -0.543704 0.270238

5 E NaN 0.509288

"""

▶ requirements.txt


numpy==2.1.2
pandas==2.2.3
python-dateutil==2.9.0.post0
pytz==2024.2
six==1.16.0
tzdata==2024.2

numpy==2.1.2

pandas==2.2.3

python-dateutil==2.9.0.post0

pytz==2024.2

six==1.16.0

tzdata==2024.2

※ pip install pandas 명령을 실행했다.