text: import numpy as np
  
  import pandas as pd
  
  
  df1 = pd.DataFrame(np.ones((3,4))*0,columns=['a','b','c','d'])
  
  df2 = pd.DataFrame(np.ones((3,4))*1,columns=['a','b','c','d'])
  
  df3 = pd.DataFrame(np.ones((3,4))*2,columns=['a','b','c','d'])
  
  print(df1)
  print(df2)
  print(df3)
  
  #ignore_index 会将index进行重新重排
  res = pd.concat([df1,df2,df3],axis=0,ignore_index=True)
  
  print(res)
  
  res = pd.concat([df1,df2,df3],axis=1,ignore_index=True)  
  print(res)
  
  
  #join,['inner','outer' 默认为outer]   以下两个df有所不同
  df4 = pd.DataFrame(np.ones((3,4))*0,index=[1,2,3],columns=['a','b','c','d'])
  
  df5 = pd.DataFrame(np.ones((3,4))*1,index=[2,3,4],columns=['b','c','d','e'])
  
  print(df4)
  print(df5)
  #默认axis为0
  res = pd.concat([df4,df5],axis=0,join='inner',ignore_index=True)
  print(res)
  
  #join_axes
  #按照df4的索引进行合并，df5中有的，但df4中没有的不输出来
  res = pd.concat([df4,df5],axis=1,join_axes=[df4.index])  
  print(res)
  
  #append  默认往下加数据 即axis=0
  res = df1.append([df2,df3],ignore_index=True)
  print(res)
  
  #添加一条数据
  s1 = pd.Series([1,2,3,4],index=['a','b','c','d'])
  res = df1.append(s1,ignore_index=True)
  print(res)
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  