I'm wondering if there is any Perl function that acts as inverse of substr. If substr selects a part of the string defined by coordinates, this function skips this part and instead captures string parts flanking given coordinates.
It can be just done using substr with coordinates I want for each flank, but I was wondering if there is something built-in for such cases.
Easiest and fastest way is probably to use four-parameter substring.
use strict;
use warnings;
use feature 'say';
my $orig = 'aaabbbccc';
my $middle = substr( $orig, 3, 3 );
substr( my $flanks = $orig, 3, 3, '/' );
say $orig; # aaabbbccc
say $middle; # bbb
say $flanks; # aaa/ccc
If you don't want the slash in the output, then substr( my $flanks = $orig, 3, 3, '' ).
This can be handled with substr(), if you add some Perl logic. substr() can be used to delete part of a string by adding an empty string as REPLACEMENT, as denoted in the documentation:
substr EXPR,OFFSET,LENGTH,REPLACEMENT
For example, you can do this:
my $org = "foo bar baz";
my $flank = $org;
my $mid = substr($flank, 4, 3, '');
print "Original: $org\nMid: $mid\nFlank: $flank\n";
Which will print this:
Original: foo bar baz
Mid: bar
Flank: foo baz