Replace space with tab between square bracket

amparida has asked for the wisdom of the Perl Monks concerning the following question:

Hi, I need help to Replace space with tab inside square bracket. input:

[8/29/2013 7:16:45 AM] User abc def [DEFAULT]
[8/29/2013 7:16:45 AM] User xyz abc [DEFAULT]
[download]

Output:

[8/29/2013<tab>7:16:45<tab>AM] User abc def [DEFAULT]
[8/29/2013<tab>7:16:45<tab>AM] User xyz abc [DEFAULT]
[download]

I know how to replace. But need help to do this replace operation for the string present in square bracket. Regards, amiya here my code

#!/usr/bin/perl -w

use strict;


open(FILE, "<input.txt") || die "File not found";
my @lines = <FILE>;
close(FILE);

my @newlines;
foreach(@lines) {

$_ =~ s/\s+/\t/g;
push(@newlines,"$_\n");
  
}
my $file = "output.txt";
unlink $file;
open(FILE, '>>',$file) || die "FILE not found";
print FILE @newlines;

close(FILE);
print "Done \n";

input.txt: 
[8/29/2013 7:16:45 AM] User abc def [DEFAULT]
[8/29/2013 7:16:45 AM] User xyz abc [DEFAULT]

output.txt: with my code
[8/29/2013<tab>7:16:45<tab>AM]<tab>User<tab>abc<tab>def<tab>[DEFAULT]
[8/29/2013<tab>7:16:45<tab>AM]<tab>User<tab>xyz<tab>abc<tab>[DEFAULT]

Output.txt:(expected)
[8/29/2013<tab>7:16:45<tab>AM] User abc def [DEFAULT]
[8/29/2013<tab>7:16:45<tab>AM] User xyz abc [DEFAULT]
[download]

Comment on Replace space with tab between square bracket Select or Download Code

Replies are listed 'Best First'.
Re: Replace space with tab between square bracket by kcott (Archbishop) on Aug 31, 2013 at 12:57 UTC
G'day amparida, Welcome to the monastery. Your problem is "`$_ =~ s/\s+/\t/g;`" which targets all spaces, not just those within the brackets. If you have Perl 5.14.0 (or later), you can do this: `$ perl -Mstrict -Mwarnings -E ' my $x = "[8/29/2013 7:16:45 AM] User abc def [DEFAULT]"; $x =~ s{\[([^\]])\]}{"[" . $1 =~ y/ /\t/r . "]"}eg; say $x; ' \| cat -vet [8/29/2013^I7:16:45^IAM] User abc def [DEFAULT]$` [download] For earlier versions, this works: `$ perl -Mstrict -Mwarnings -E ' my $x = "[8/29/2013 7:16:45 AM] User abc def [DEFAULT]"; $x =~ s{\[([^\]])\]}{"[" . do { (my $y = $1) =~ y/ /\t/; $y } . " +]"}eg; say $x; ' \| cat -vet [8/29/2013^I7:16:45^IAM] User abc def [DEFAULT]$` [download] [Note: `cat -vet` shows tabs as "`^I`" and newlines as "`$`".] Update (Perl version clarification): My reference to Perl 5.14.0 relates to the use of the '`r`' modifier in '`y/ /\t/r`'. After posting, I noticed I'd also used '`-E`' and '`say $x;`'; for versions prior to 5.10.0, use '`-e`' and '`print "$x\n";`'. -- Ken	[reply] [d/l] [select]
Re^2: Replace space with tab between square bracket by amparida (Initiate) on Aug 31, 2013 at 13:09 UTC
thank you very much Ken. It is working.	[reply]
Re: Replace space with tab between square bracket by toolic (Bishop) on Aug 31, 2013 at 12:15 UTC
Update your post using code tags for your input data: Writeup Formatting Tips Show the code you've tried. Show the output you expect (in code tags).	[reply]
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Re: Replace space with tab between square bracket by hdb (Monsignor) on Aug 31, 2013 at 12:52 UTC
In split, using parentheses in the regular expression captures the separators as well. So `split /(\[.?\])/` will split your string into the pieces in brackets and the others assuming a well-formed input and no nesting. Then do the replacing and join everything together again. `use strict; use warnings; my $input = '[8/29/2013 7:16:45 AM] User abc def [DEFAULT] [8/29/2013 +7:16:45 AM] User xyz abc [DEFAULT]'; my $output = join '', map { s/\s/\t/g if /\[/; $_ } split /(\[.?\])/, + $input; print "$output\n";` [download]	[reply] [d/l] [select]