How to sum some columns in a row

Question

I have:

df = pd.DataFrame({
  "ID": [55218,55218,55218,55222],
  "Cluster": [0,0,1,1],  
  "Rating":[-1,2,0,2]})

I want to sum the Rating of e.g. Cluster "0" for every "ID"

My expected output is:

df_new = pd.DataFrame({
  "ID": [55218,55218,55218,55222], 
  "Cluster": [0,1,1], 
  "Sum": [1,0,2] })

Please retake the [tour], read [what's on-topic here](/help/on-topic), [ask], and the [question checklist](//meta.stackoverflow.com/q/260648/843953), and provide a [mre]. "Implement this feature for me" is off-topic for this site. You have to _make an honest attempt_, and then ask a _specific question_ about your algorithm or technique. — Pranav Hosangadi, Nov 03 '20 at 16:11

score -1 · Accepted Answer · answered Nov 03 '20 at 16:12

-1

Use groupby

df.groupby("ID")["Cluster"].sum().reset_index()

answered Nov 03 '20 at 16:12

Wasif

2

Questions as basic as this one have usually been asked and answered. Please look for duplicates before posting simple, one-line answers. – Pranav Hosangadi Nov 03 '20 at 16:16

1 Answers1