pandas的连接函数concat()函数的具体使用方法

pd.concat(objs, axis=0, join='outer', join_axes=None, ignore_index=False,
     keys=None, levels=None, names=None, verify_integrity=False,
     copy=True)

In [1]: df1 = pd.DataFrame({'A': ['A0', 'A1', 'A2', 'A3'],
  ...:           'B': ['B0', 'B1', 'B2', 'B3'],
  ...:           'C': ['C0', 'C1', 'C2', 'C3'],
  ...:           'D': ['D0', 'D1', 'D2', 'D3']},
  ...:           index=[0, 1, 2, 3])
  ...: 
 
In [2]: df2 = pd.DataFrame({'A': ['A4', 'A5', 'A6', 'A7'],
  ...:           'B': ['B4', 'B5', 'B6', 'B7'],
  ...:           'C': ['C4', 'C5', 'C6', 'C7'],
  ...:           'D': ['D4', 'D5', 'D6', 'D7']},
  ...:           index=[4, 5, 6, 7])
  ...: 
 
In [3]: df3 = pd.DataFrame({'A': ['A8', 'A9', 'A10', 'A11'],
  ...:           'B': ['B8', 'B9', 'B10', 'B11'],
  ...:           'C': ['C8', 'C9', 'C10', 'C11'],
  ...:           'D': ['D8', 'D9', 'D10', 'D11']},
  ...:           index=[8, 9, 10, 11])
  ...: 
 
In [4]: frames = [df1, df2, df3]
 
In [5]: result = pd.concat(frames)

result = pd.concat(frames, keys=['x', 'y', 'z'])

In [8]: df4 = pd.DataFrame({'B': ['B2', 'B3', 'B6', 'B7'],
  ...:         'D': ['D2', 'D3', 'D6', 'D7'],
  ...:         'F': ['F2', 'F3', 'F6', 'F7']},
  ...:         index=[2, 3, 6, 7])
  ...: 
 
In [9]: result = pd.concat([df1, df4], axis=1)

In [10]: result = pd.concat([df1, df4], axis=1, join='inner')

In [11]: result = pd.concat([df1, df4], axis=1, join_axes=[df1.index]) #设置索引为df1的索引