如何连接两个熊猫数据框

Question

I have two pandas data frames:

df1
    id frid title
    1  1    abc
    2  1    ddd
    3  2    ghc
    4  3    frg
    5  1    def

df2
    frid comment
    1    w
    2    s
    3    e

Now I want to merge these two data frames based on the field frid . In other words, I want to add column comment to df1 . How can I do this? I know about join command, but it works differently ( df1.join(df2) ).

The result should be:

df
    id frid title comment
    1  1    abc   w
    2  1    ddd   w
    3  2    ghc   s
    4  3    frg   e
    5  1    def   w

Answer 1

use merge and pass the column you want to merge on, by default this performs an 'inner' merge:

In [198]:
df1.merge(df2, on='frid')

Out[198]:
   id  frid title comment
0   1     1   abc       w
1   2     1   ddd       w
2   5     1   def       w
3   3     2   ghc       s
4   4     3   frg       e