Add a column to a CSV that's a sum of the two previous columns

Question

I am trying to manipulate a big data set, but I will use a simple example here. I am trying to add two columns to form a third column.

Input CSV

Desired Output CSV

1,11,12
2,12,14
3,13,16
4,14,18
5,15,20

I have been trying the below line and I am getting the wrong output.

awk -F, '{$3=$1+$2;} {print $1,$2,$3}' OFS=, filename.csv

@terdon i have used multiple csv file types and my results always come out jumbled together. I am just using small data sets but need this to work at scale. It works with just using a two column output but once I try to add the third I run into problems. — hmm1050, Apr 29 '17 at 0:52

steve · Accepted Answer · 2017-04-27 19:26:15Z

3

Either of these:

awk -F, '{print $1","$2","$1+$2}' filename.csv
awk -F, '{$0=$1","$2","$1+$2}1' filename.csv

And for what it's worth, your example in the question worked fine for me. Locally and via awk.js.org tool.

$ awk -F, '{$3=$1+$2;} {print $1,$2,$3}' OFS=, filename.csv
1,11,12
2,12,14
3,13,16
4,14,18
5,15,20
$

answered Apr 27 '17 at 19:09

steve

15.1k2 gold badges29 silver badges56 bronze badges

1

whoa, awk REPL! nice – Neil McGuigan Apr 27 '17 at 19:47
@steve I am working from both the unix and linux cmd line, and my results keep getting jumbled like so, ,110 ,131 ,152 ,173 ,194 ,215 ,236 ,257 9,18,27 – hmm1050 Apr 29 '17 at 0:46

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LittleSmurfie · Accepted Answer · 2017-04-27 19:05:45Z

1

awk -F ',' '{$3=$1+$2;} {print $1","$2","$3}' filename.csv

answered Apr 27 '17 at 19:05

LittleSmurfie

1876 bronze badges

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2 Answers 2