How to increment a column value with an increasing number in a csv file

Question

I have a text file with 3 columns as below.

$ cat test.txt
1,A,300
1,B,300
1,C,300

Till now i have tried as, awk -F, '{$3=$3+1;print}' OFS=, test.txt

But output is coming as:

1,A,301
1,B,301
1,C,301

& below is my desired output

Now i want to increment the third column only, the output should be like below

1,A,300
1,B,301
1,C,302

How can I achieve the desired output?

If any of the following answer helped you in your goal please accept/upvote the answer for closure by ticking right sign besides the answer. — P...., Mar 27 '17 at 11:05

NeronLeVelu · Answer 1 · 2017-02-02T10:47:42.527

3

could be, assuming line are sequential like your sample)

awk -F ',' '{sub($3"$",$3+NR-1)}7' YourFile

it use the line numer as increment value, changing the line end and not the field value (different from an awk POV, that don't need to rebuild the line with separator)

Alternative if empty or other line between modifiable lines (i arbitrary use NF as filter but it depend of your criteria if any)

awk -F ',' 'NF{sub($3"$",$3+i++)}7' YourFile

edited Feb 02 '17 at 10:47

answered Feb 02 '17 at 09:36

NeronLeVelu

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What is "7" in this example? – Sebastian Aug 15 '21 at 11:57
any number other than 0 will print the current line. 7 is a private joke with some other awk writer – NeronLeVelu Sep 09 '21 at 12:02

score 2 · Answer 2 · edited Nov 22 '20 at 16:03

2

 awk 'BEGIN{x=0;FS=OFS=","} NF>1{$3=$3+x;x++}1' inputfile
1,A,300

1,B,301

1,C,302

Explanation:

BEGIN Block : It contains x which is a counter initially set to zero, FS and OFS . /./ is used to ignore blank lines(Remove this part if there are no blank lines). $3=$3+x : This will add the value of counter to $3. x++ : To increment the current value of the counter.

edited Nov 22 '20 at 16:03

JohnC

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answered Feb 02 '17 at 05:43

P....

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x=0 could be omitted, its 0 by default if used as adding value for unassigned variable. your `x++` could be directly included in `$3=$3+x++`, and `$3=$3+` could be rewrite with `$3+=`. your /./ is also at risk with space line, use maybe a `NF > 1` or `/[^[:blank:]]/`. Your code is correct, do the job so worth the +1 – NeronLeVelu Feb 02 '17 at 09:45

score 0 · Answer 3 · answered Feb 02 '17 at 05:42

0

try this NR starts at 1 so NR -1 should give you the correct number

 awk -F, '{$3=$3+NR-1;print}' OFS=, test.txt

answered Feb 02 '17 at 05:42

Mitesh Pant

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James Brown · Answer 4 · 2017-02-02T08:23:46.360

0

Yet another:

awk 'BEGIN{ FS=OFS="," } ($3+=i++)||1 ' file

edited Feb 02 '17 at 08:23

answered Feb 02 '17 at 05:51

James Brown

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1

Note that this will skip lines where `$3 + i == 0`. – Thor Feb 02 '17 at 07:45
2

For a golfed version I would go with: `awk '{$3+=i++} 1' FS=, OFS=,`. – Thor Feb 02 '17 at 07:48
empty lines have now an `,,3` in my case (sample of OP is ambiguous about space between lines with `,`) – NeronLeVelu Feb 02 '17 at 09:47
2

@NeronLeVelu: Right, avoid it by checking for empty lines: `NF {$3+=i++} 1` – Thor Feb 02 '17 at 10:11
@Thor just learn with your comment that NF is 0 if empty line and not 1 as i supected (1 with empty field value) – NeronLeVelu Feb 02 '17 at 10:33

Ramya · Answer 5 · 2020-01-21T04:43:10.163

-1

awk 'BEGIN{i=0;FS=OFS=","} NF>1{$3=$3+i;i++}1' filename

It contains x which is a counter initially set to zero, FS and OFS . /./ is used to ignore blank lines(Remove this part if there are no blank lines).

$3=$3+i : This will add the value of counter to $3. i++ : To increment the value of counter. Must and should give space betwen awk and begin as well as filename and end of the file

edited Jan 21 '20 at 04:43

answered Jan 21 '20 at 04:34

Ramya

1
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Thanks for your contribution, however, the answer is not readable, can you please format it and add more details? – Sid Jan 21 '20 at 05:34

How to increment a column value with an increasing number in a csv file

5 Answers5