create hashes using regex

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

SO basically I have a file that looks like this

TCONS_00000047 XLOC_000039

TCONS_00000718 XLOC_000456

TCONS_00000938 XLOC_000610

TCONS_00004086 XLOC_002872

TCONS_00004252 XLOC_003003

TCONS_00004975 XLOC_003624

TCONS_00004976 XLOC_003624

TCONS_00005492 XLOC_004020

there are more like that . How do i declare a hash for all the keys and variables at once? This is what i did

open(IN, $file)||die "Can not open file: $file\n";

%hash =( 'TCONS_00[0-9]+' => 'XLOC_[0-9]+');


@keys= keys %hash;
@values= values %hash;

print @keys;
print @values;

close(IN);
[download]

The hash took the key as a string, not a regex operation. What can i do?

Comment on create hashes using regex Download Code

Replies are listed 'Best First'.
Re: create hashes using regex by hdb (Monsignor) on Jun 12, 2013 at 17:45 UTC
Well, for one you do not link your file or file handle in any way to the declaration of the hash. How shall Perl know that you want to apply those expressions to the contents of your file? Also, regular expression matching is done using the `m//` operator or `/regexp/`. Nowhere you tell Perl that you expect matching. Thirdly, you need to use capture groups `(...)` in regular expressions to retrieve information. And then you need to loop some how over the lines of your file or apply the regexes repeatedly in some way. If you put these points into action, it could look like the code below. I am reading from the DATA handle for convenience and read all lines into an unnamed array. `use strict; use warnings; my %hash = map { /(TCONS_00[0-9]+)\s+(XLOC_[0-9]+)/ } <DATA>; my @keys= keys %hash; my @values= values %hash; print "@keys\n"; print "@values\n"; __DATA__ TCONS_00000047 XLOC_000039 TCONS_00000718 XLOC_000456 TCONS_00000938 XLOC_000610 TCONS_00004086 XLOC_002872 TCONS_00004252 XLOC_003003 TCONS_00004975 XLOC_003624 TCONS_00004976 XLOC_003624 TCONS_00005492 XLOC_004020` [download]	[reply] [d/l] [select]
Re^2: create hashes using regex by bingalee (Acolyte) on Jun 12, 2013 at 18:33 UTC
thank you so much..	[reply]
Re: create hashes using regex by frozenwithjoy (Priest) on Jun 12, 2013 at 17:54 UTC
Here is a non-regex solution, too: `#!/usr/bin/env perl use strict; use warnings; my %hash = map { chomp; split /\t/; } <DATA>; use Data::Printer; p %hash; __DATA__ TCONS_00000047 XLOC_000039 TCONS_00000718 XLOC_000456 TCONS_00000938 XLOC_000610 TCONS_00004086 XLOC_002872 TCONS_00004252 XLOC_003003 TCONS_00004975 XLOC_003624 TCONS_00004976 XLOC_003624 TCONS_00005492 XLOC_004020` [download] Output: `{ TCONS_00000047 "XLOC_000039", TCONS_00000718 "XLOC_000456", TCONS_00000938 "XLOC_000610", TCONS_00004086 "XLOC_002872", TCONS_00004252 "XLOC_003003", TCONS_00004975 "XLOC_003624", TCONS_00004976 "XLOC_003624", TCONS_00005492 "XLOC_004020" }` [download]	[reply] [d/l] [select]
Re: create hashes using regex by Cristoforo (Curate) on Jun 12, 2013 at 19:07 UTC
Another way (slurping the entire file into 1 string). `#!/usr/bin/perl use strict; use warnings; my $file = <<EOF; TCONS_00000047 XLOC_000039 TCONS_00000718 XLOC_000456 TCONS_00000938 XLOC_000610 TCONS_00004086 XLOC_002872 TCONS_00004252 XLOC_003003 TCONS_00004975 XLOC_003624 TCONS_00004976 XLOC_003624 TCONS_00005492 XLOC_004020 EOF open my $fh, "<", \$file; my $slurp; do {local $/; $slurp = <$fh>}; my %hash = split ' ', $slurp; use Data::Dumper; print Dumper \%hash;` [download] `$VAR1 = { 'TCONS_00004086' => 'XLOC_002872', 'TCONS_00004976' => 'XLOC_003624', 'TCONS_00004975' => 'XLOC_003624', 'TCONS_00000718' => 'XLOC_000456', 'TCONS_00000047' => 'XLOC_000039', 'TCONS_00005492' => 'XLOC_004020', 'TCONS_00000938' => 'XLOC_000610', 'TCONS_00004252' => 'XLOC_003003' };` [download]	[reply] [d/l] [select]
Re: create hashes using regex by Laurent_R (Canon) on Jun 12, 2013 at 17:49 UTC
A quick try under the Perl debugger: `DB<1> $c = "TCONS_00000047 XLOC_000039"; DB<2> %h = map { $1, $2 if /(TCONS_00[0-9]+) (XLOC_[0-9]+)/; } ($c); DB<3> x %h 0 'TCONS_00000047' 1 'XLOC_000039'` [download] EDIT: HDB typed faster than me. ;-)	[reply] [d/l]