Simple counter

[ooids]

Hi,

I have a simple input file:
1
1
1
1
2
2
2
2
3
3
3

I need to create an additional column in the file which is based on the first columns numbers:

1 1
1 2
1 2
1 3
2 1
2 2
2 2
2 3
3 1
3 2
3 3

etc

Any ideas would be great!

Many Thanks

 

[feherke]

Hi

Assuming that doubling the "2" lines is a typo ( you provided no rule for that ) :

awk 'l!=$1{l=$1;i=0}{$2=++i}1' /input/file

Feherke.

http://rootshell.be/~feherke/

 

[ooids]

Hi Feherke,

No typos.
The first new occurrence of a number = 1
Subsequent occurrences of the same number = 2
The last occurrence of the number = 3

Hope that makes sense - what I am struggling with is being able to compare the current line with the previous one so I know when the number changes

Thanks!

 

[PHV]

One way:
awk 'function p(){if{print l"\t1";for(i=2;i<n;++i)print l"\t2";if(n>1)print l"\t3"}}l!=$1{p();n=0;l=$1}{++n}END{p()}' /path/to/input

Hope This Helps, PH.
FAQ219-2884
FAQ181-2886

 

[ooids]

Many thanks!