两表拼接 pd.concat

a = pd.DataFrame([[1,2,3],

                  [4,5,6],

                  [7,8,9]],columns=['a','b','c'])

b = pd.DataFrame([[11,23,45],

                  [22,23,24],

                  [31,32,33]],columns=['a','b','c'])

pd.concat([a,b],axis=0,ignore_index=True)