Concatenate strings from several rows using Pandas groupby

Question

I want to merge several strings in a dataframe based on a groupedby in Pandas    This is my code so far   import pandas as pd from io import StringIO  data   StringIO      name1   hej   2014-11-01   name1   du   2014-11-02   name1   aj   2014-12-01   name1   oj   2014-12-02   name2   fin   2014-11-01   name2   katt   2014-11-02   name2   mycket   2014-12-01   name2   lite   2014-12-01          load string as stream into dataframe df   pd read csv data header 0  names   name   text   date   parse dates  2      add column with month df  month     df  date   apply lambda x  x month    I want the end result to look like this     I don t get how I can use groupby and apply some sort of concatenation of the strings in the column  text   Any help appreciated

User · Answer

we can groupby the  name  and  month  columns  then call agg   functions of Panda   s DataFrame objects   The aggregation functionality provided by the agg   function allows multiple statistics to be calculated per group in one calculation   df groupby   name    month    as index   False  agg   text       join

User · Answer

The answer by EdChum provides you with a lot of flexibility but if you just want to concateate strings into a column of list objects you can also   output series   df groupby   name   month     text   apply list

User · Answer

If you want to concatenate your  quot text quot  in a list  df groupby   name    month    as index   False  agg   text   list

User · Answer

For me the above solutions were close but added some unwanted  n s and dtype object  so here s a modified version   df groupby   name    month     text   apply lambda text     join text to string index False    str replace     n        reset index

User · Answer

You can groupby the  name  and  month  columns  then call transform which will return data aligned to the original df and apply a lambda where we join the text entries   In  119    df  text     df   name   text   month    groupby   name   month     text   transform lambda x      join x   df   name   text   month    drop duplicates   Out 119       name         text  month 0  name1       hej du     11 2  name1        aj oj     12 4  name2     fin katt     11 6  name2  mycket lite     12   I sub the original df by passing a list of the columns of interest df   name   text   month    here and then call drop duplicates  EDIT actually I can just call apply and then reset index   In  124    df groupby   name   month     text   apply lambda x      join x   reset index    Out 124       name  month         text 0  name1     11       hej du 1  name1     12        aj oj 2  name2     11     fin katt 3  name2     12  mycket lite   update  the lambda is unnecessary here   In 38   df groupby   name   month     text   apply     join  reset index    Out 38        name  month         text 0  name1     11           du 1  name1     12        aj oj 2  name2     11     fin katt 3  name2     12  mycket lite

[python-3.x] Concatenate strings from several rows using Pandas groupby

Examples related to python-3.x

Examples related to pandas

Examples related to pandas-groupby