AWK - calculated field

Author

calculated field

Matias Woloski

2004-05-04, 12:53 pm

Supose I have this file
001; DESC1; 0,231; 23100
002; DESC2; 0,312; 31200
001; DESC1; 0,169; 16900

I need to modify the fourth field of each record of a file, overwriting all
the values. The value 23100 is a multiplication between 0,231 and K, which
in this case is 100000.

Is awk suitable for this task? any hints?

thanks,
Matias

Barry Margolin

2004-05-04, 12:53 pm

In article <c773ok$emp5$1@ID-148083.news.uni-berlin.de>,
"Matias Woloski" <woloski@sion.com> wrote:

> Supose I have this file
> 001; DESC1; 0,231; 23100
> 002; DESC2; 0,312; 31200
> 001; DESC1; 0,169; 16900
>
> I need to modify the fourth field of each record of a file, overwriting all
> the values. The value 23100 is a multiplication between 0,231 and K, which
> in this case is 100000.
>
> Is awk suitable for this task? any hints?

awk '{$4 = <new value>; print}' oldfile > newfile

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***

Icarus Sparry

2004-05-04, 12:53 pm

On Tue, 04 May 2004 00:47:41 -0300, Matias Woloski wrote:

> Supose I have this file
> 001; DESC1; 0,231; 23100
> 002; DESC2; 0,312; 31200
> 001; DESC1; 0,169; 16900
>
> I need to modify the fourth field of each record of a file, overwriting all
> the values. The value 23100 is a multiplication between 0,231 and K, which
> in this case is 100000.
>
> Is awk suitable for this task? any hints?

Awk is very suitable.

awk 'BEGIN {k=100000 ;FS=";"; OFS=";"} { f3=$3 ; sub(",",".",f3) ; $4=f3*k; print}'

or

awk -F';' '{ f3=$3 ; sub(",",".",f3) ; $4=f3*100000 ; printf("%s; %s; %s; %d\n",$1,$2,$3,$4) }'

will do it. Some versions of awk may be less us-centric, and therefore
understand a "decimal comma" instead of a "decimal point", particularly if
you have the correct locale settings. If so you can avoid all the mucking
around with f3 etc and write

awk 'BEGIN {k=100000 ;FS=";"; OFS=";"} { $4=$3*k; print}'

William Park

2004-05-04, 12:53 pm

In <comp.lang.awk> Matias Woloski <woloski@sion.com> wrote:
> Supose I have this file
> 001; DESC1; 0,231; 23100
> 002; DESC2; 0,312; 31200
> 001; DESC1; 0,169; 16900
>
> I need to modify the fourth field of each record of a file, overwriting all
> the values. The value 23100 is a multiplication between 0,231 and K, which
> in this case is 100000.
>
> Is awk suitable for this task? any hints?

Yes. Hint:
awk '{print 0.123 * 100000}'

--
William Park, Open Geometry Consulting, <opengeometry@yahoo.ca>
Linux solution/training/migration, Thin-client

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