【pandas】データ結合メソッド pd.concat()を利用してデータを結合する

pd.concat([df1,df2])

import pandas as pd

df1 = pd.DataFrame({'A': [1, 2], 'B': [3, 4]})
df2 = pd.DataFrame({'A': [5, 6], 'B': [7, 8]})

result = pd.concat([df1, df2])
print(result)

   A  B
0  1  3
1  2  4
0  5  7
1  6  8

 pd.concat([df1, df2], axis =1)

   A  B  A  B
0  1  3  5  7
1  2  4  6  8

pd.concat([df1, df2],ignore_index = False)

   A  B
0  1  3
1  2  4
0  5  7
1  6  8

pd.concat([df1, df2],ignore_index = True)

   A  B
0  1  3
1  2  4
2  5  7
3  6  8

pd.concat([df1, df2],keys = ["df1","df2"])

pd.concat([df1, df2],keys = ["df1","df2"])

       A  B
df1 0  1  3
    1  2  4
df2 0  5  7
    1  6  8

pd.concat([df1, df2],keys = ["df1","df2"],names = ["DataFrame","number"])

                  A  B
DataFrame number
df1       0       1  3
          1       2  4
df2       0       5  7
          1       6  8

import pandas as pd

df1 = pd.DataFrame({'A': [1, 2], 'B': [3, 4], 'C' :[2,4]})
df2 = pd.DataFrame({'A': [5, 6], 'B': [7, 8]})

result = pd.concat([df1, df2],join="inner")
print(result)

   A  B
0  1  3
1  2  4
0  5  7
1  6  8

import pandas as pd

df1 = pd.DataFrame({'A': [1, 2], 'B': [3, 4], 'C' :[2,4]})
df2 = pd.DataFrame({'A': [5, 6], 'B': [7, 8]})

result = pd.concat([df1, df2],join="inner")
print(result)

import pandas as pd

df1 = pd.DataFrame({'A': [1, 2], 'B': [3, 4], 'C' :[2,4]})
df2 = pd.DataFrame({'A': [5, 6], 'B': [7, 8]})

result = pd.concat([df1, df2],join="outer")
print(result)

   A  B    C
0  1  3  2.0
1  2  4  4.0
0  5  7  NaN
1  6  8  NaN

import pandas as pd

# サンプル DataFrame を作成
df1 = pd.DataFrame({'A': [1, 2], 'B': [3, 4]})
df2 = pd.DataFrame({'A': [5, 6], 'B': [7, 8]}, index=[1, 2])

# verify_integrity を True にして連結する
try:
    result = pd.concat([df1, df2], verify_integrity=True)
except ValueError as e:
    print("ValueError:", e)

ValueError: Indexes have overlapping values: Int64Index([0, 1], dtype='int64')