CODEWITHSUNDEEP
regexperl
KT8
KT8

Reputation: 181

Undefined Match Found in Perl Regex Array

I have a string (e.g. '24G22') which I am trying to split into separate elements of numbers and character (i.e. 24, G, 22). For which, I wrote the regular expression as shown below.

However, for some weird reason, I get alot of undefined elements in my array which I had expected to be of the form:

@array = ('24','G', '22')

instead of

@array = ('24', undef, undef, 'G', '22', undef)

which I get from the output

Could someone help explain to me the cause of the error and how I could rectify the error and get my desired output?

Script

#!/usr/bin/perl

use strict;
use warnings;

my $string = '24G22';
my @array = ( $string =~ m/([0-9]+)|([ATGCN]+)/g );
print join("\n", @array);

Output

$ ./test_debug.pl
Use of uninitialized value $array[1] in join or string at ./test_debug.pl line 8.
Use of uninitialized value $array[2] in join or string at ./test_debug.pl line 8.
Use of uninitialized value $array[5] in join or string at ./test_debug.pl line 8.
24


G
22

Upvotes: 0

Views: 755

Answers (1)

Toto
Toto

Reputation: 91488

Just group in one group:

my @array = ( $string =~ m/([0-9]+|[ATGCN]+)/g );

because you have to catch only one group for each match.

With yours, you're matching 2 groups each times and one of them is empty.

Upvotes: 1

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