pandas merge dataframe with NaN (or “unknown”) for missing values

Question

I have 2 dataframes, one of which has supplemental information for some (but not all) of the rows in the other.

names = df({\'names\':[\'bob\',\'frank\',\'james\         


        

Answer 1

I think you want to perform an outer merge:

In [60]:

pd.merge(names, info, how='outer')
Out[60]:
     names position classification
0      bob      dev            NaN
1    frank      dev          thief
2    james      dev            NaN
3      tim      sys           good
4  ricardo      sys            NaN
5     mike      sys            NaN
6     mark      sup          thief
7     joan      sup            NaN
8      joe      sup          thief

There is section showing the type of merges can perform: http://pandas.pydata.org/pandas-docs/stable/merging.html#database-style-dataframe-joining-merging