python中merge与concat区别_python 合并(merge , concat , join , combine_first)
Merge1首先建立两个新的DataFrameimportpandasaspdimportnumpyasnpdf1=pd.DataFrame({'key':['a','b','c','d','e'],'data2':np.arange(5)})df2=pd.DataFrame({'key':['a','b','c'],'data1':np.arange(3)})In[238]:df1Out[238