please Perl help...

Hi All,

I'm new to this group also for perl but nowadays I working around with
Perl and I need some help. this my first thread please anyone can help
me?

i have a file contains the following data.

charith 4 matara
saman 8 kandy
andrew 9 colombo
dilshan 3 galle
shanil 10 jafna
..
..
..
Here I want to replace second column (Number) with incremental number
sequence. output should be following.

charith 0 matara
saman 1 kandy
andrew 2 colombo
dilshan 3 galle
shanil 4 jafna
..
..
..

Thank you very much


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Re: please Perl help...

ׁHi Charith,

On Fri, 2 Sep 2011 20:42:31 -0700 (PDT)
Charith LokuBogahawatta wrote:

> Hi All,
>=20
> I'm new to this group also for perl but nowadays I working around with
> Perl and I need some help. this my first thread please anyone can help
> me?
>=20
> i have a file contains the following data.
>=20
> charith 4 matara
> saman 8 kandy
> andrew 9 colombo
> dilshan 3 galle
> shanil 10 jafna
> .
> .
> .
> Here I want to replace second column (Number) with incremental number
> sequence. output should be following.
>=20
> charith 0 matara
> saman 1 kandy
> andrew 2 colombo
> dilshan 3 galle
> shanil 4 jafna
> .
> .
> .

You can do it from the command line like:

shlomif@lap:~$ cat test.txt
charith 4 matara
saman 8 kandy
andrew 9 colombo
dilshan 3 galle
shanil 10 jafna
shlomif@lap:~$ perl -lan -e '$F[1] =3D ($counter++); print "@F";' test.txt=
=20
charith 0 matara
saman 1 kandy
andrew 2 colombo
dilshan 3 galle
shanil 4 jafna
shlomif@lap:~$=20

Note that the '...' delimiters won't work on Microsoft Windows, and you'll
need to use "..." instead. See http://perldoc.perl.org/perlrun.html for more
explanation on what I did here.=20

You can also use the -i flag (also from perlrun) to edit the file in-place.

Regards,

Shlomi Fish

>=20
> Thank you very much
>=20
>=20



--=20
------------------------------------------------------------ -----
Shlomi Fish http://www.shlomifish.org/
My Favourite FOSS - http://www.shlomifish.org/open-source/favourite/

â€=9CWeâ€=99re not doing it for moneyâ€=A6 weâ€=99re doing =
it for a shitload of money!â€=9D
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Re: please Perl help...

use strict;
use warnings;
while(){
my $num =3D $. - 1;
s/\d+/$num/ if /\w+\s+\d+\s+\w/;
print $_;
}

__DATA__
charith 4 matara
saman 8 kandy
andrew 9 colombo
dilshan 3 galle
shanil 10 jafna


Parag

On Fri, Sep 2, 2011 at 8:42 PM, Charith LokuBogahawatta
wrote:
> Hi All,
>
> I'm new to this group also for perl but nowadays I working around with
> Perl and I need some help. this my first thread please anyone can help
> me?
>
> i have a file contains the following data.
>
> charith 4 matara
> saman 8 kandy
> andrew 9 colombo
> dilshan 3  galle
> shanil 10 jafna
> .
> .
> .
> Here  I want to replace second column (Number) with incremental numb=
er
> sequence. output should be following.
>
> charith 0 matara
> saman 1 kandy
> andrew 2 colombo
> dilshan 3  galle
> shanil  4 jafna
> .
> .
> .
>
>  Thank you very much
>
>
> --
> To unsubscribe, e-mail: beginners-unsubscribe@perl.org
> For additional commands, e-mail: beginners-help@perl.org
> http://learn.perl.org/
>
>
>

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Re: please Perl help...

>>>>> "PK" == Parag Kalra writes:

PK> use strict;
PK> use warnings;

PK> while(){
PK> my $num = $. - 1;
PK> s/\d+/$num/ if /\w+\s+\d+\s+\w/;

there is no need for the if as you can just do a s/// directly. and it
can do the num part as well.

s/(\w+\s+)\d+(\s+\w+)/$1 . $. - 1 . $3/e ;

you could simplify the regex by assuming the only number is in the
middle as the data shows.

s/\d+/$. - 1/e ;


PK> print $_;

no need for the $_ as print defaults to printing it.

also please learn to edit quoted emails and to put your post below it.

uri

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Re: please Perl help...

Hi Parag,

a few comments on your code.

On Sat, 3 Sep 2011 23:38:31 -0700
Parag Kalra wrote:

> use strict;
> use warnings;
> while(){

You should expect the contents of the file to be in a different place than
__DATA__, so one should use open or *ARGV or whatever here.=20

> my $num =3D $. - 1;

This is not needed because one can use the /e flag to s///.=20

You may wish to have a counter that is external to the loop to keep consist=
ency
and not rely on line numbers.

> s/\d+/$num/ if /\w+\s+\d+\s+\w/;

The problem here is that:

1. The regular expression match is not anchored to the beginning of the lin=
e.

2. The substitution won't work properly if the first field contains digits.

A better way to do it would be:

s/\A(\S+\s+)\d+(\s+\S)/$1 . ($. - 1) . $2/e;

Regards,

Shlomi Fish

> print $_;
> }
>=20
> __DATA__
> charith 4 matara
> saman 8 kandy
> andrew 9 colombo
> dilshan 3 galle
> shanil 10 jafna
>=20
>=20
> Parag
>=20



--=20
------------------------------------------------------------ -----
Shlomi Fish http://www.shlomifish.org/
My Favourite FOSS - http://www.shlomifish.org/open-source/favourite/

Microsoft â€=94 making it all make sense. Ours.

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