How to add a new column into a dataframe based on rows of an other dataframe?

Question

I have two Dataframes : DF1(That i've just resampled): Mi_pollution.head(): Sensor_ID Time_Instant Measurement 0 10273 2013-11-01 00:00:00 46 1 10273 2013-11-01 01:00:00 51 2 10273 2013-11-01 02:00:00 39 3 10273 2013-11-01 03:00:00 30 4 10273 2013-11-01 04:00:00 37 And I have the DF2 : Pollutants.head(): Sensor_ID Sensor_Street_Name Sensor_Lat Sensor_Long Sensor_Type UOM Time_Instant 0 20020 Milano -via Carlo Pascal 45.478452 9.235016 Ammonia µg/m YYYY/MM/DD 1 17127 Milano - viale Marche 45.496067 9.193023 Benzene µg/m YYYY/MM/DD HH24:MI 2 17126 Milano -via Carlo Pascal 45.478452 9.235016 Benzene µg/m YYYY/MM/DD HH24:MI 3 6057 Milano - via Senato 45.470780 9.197180 Benzene µg/m YYYY/MM/DD HH24:MI 4 6062 Milano - P.zza Zavattari 45.476089 9.143509 Benzene µg/m YYYY/MM/DD HH24:MI And What I'm trying to to do , is to create new columns based on the pollutants and add them to DF1 and assign each measurement based on the Sensor , like This: Sensor_ID Time_Instant Ammonia Benzene Nitrogene …... 0 20020 2013-12-01 00:00:00 4.8 Nan Nan 1 20020 2013-12-01 01:00:00 5.3 Nan Nan 2 20020 2013-12-01 02:00:00 3.0 Nan Nan . . 56 14330 2013-11-01 00:00:00 Nan 6.3 Nan 57 14330 2013-11-01 01:00:00 Nan 5.3 Nan . . Any Suggestion Would be much appreciated , Thank U all. JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

Assuming you're joining on Sensor_ID (there aren't any common Sensor_IDs between the two dataframes in the small example you gave), you could merge the dfs on Sensor_ID (and possibly Time_Instant?). Then you can use pivot_table to transpose the row values (Sensor_Type) to column headings, then fill in the row values with Measurement. For example: df3 = df1.merge(df2, on='Sensor_ID', how='left')\ .pivot_table(index=['Sensor_ID','Sensor_Street_Name','Other columns'], values='Measurement', columns='Sensor_Type')\ .reset_index()