How do i found the NumTrans column sum of data.table for Cust_map==1 and 2

Question

> SS
   Cust_map Merch_Map_final TXN_MTH        SPND_CATGY NumTrans
1:        1            2412  201310 BUSINESS SERVICES        2
2:        1            2412  201401 BUSINESS SERVICES        3
3:        1            2412  201403 BUSINESS SERVICES        3
4:        1            2412  201406 BUSINESS SERVICES        3
5:        1            2412  201407 BUSINESS SERVICES        2
6:        2            2415  201310  GROCERY                 5

score 0 · Accepted Answer · edited Mar 03 '16 at 19:03

0

We can group by 'Cust_map' and get the sum of 'NumTrans'

SS[, .(NumTrans = sum(NumTrans)), by = Cust_map]

edited Mar 03 '16 at 19:03

David Arenburg

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answered Mar 03 '16 at 17:51

akrun

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How do i found the NumTrans column sum of data.table for Cust_map==1 and 2

1 Answers1