Two paths. See index, also quotemeta for  \Q \E interpolation modifiers. (Update: Note that, of course, this approach will not work if the sub-string being searched for is longer than the target string; e.g.,  'helper' will not match to anything in the  @WORDS example array below.) 

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @WORDS = qw(trying helping doing do xdo help hel xhelp);
 my $s = 'help';
 ;;
 my @hits = grep m{ \A \Q$s\E }xms, @WORDS;
 dd \@hits;
 ;;
 $s = 'do';
 @hits = grep index($_, $s) == 0, @WORDS;
 dd \@hits;
 ;;
 dd \@WORDS;
"
["helping", "help"]

["doing", "do"]

["trying", "helping", "doing", "do", "xdo", "help", "hel", "xhelp"]

[download]

Update: If the strings being compared can be of any length relative to each other, here's a way to find strings that are identical at their beginnings. (This can easily be changed to find strings identical at their ends by throwing in a couple of reverse function calls.) 

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @words = qw(he xhelper hello hel help helper helping);
 my $t = 'helper';
 ;;
 my @hits = grep overlap($_, $t, 3), @words;
 dd \@hits;
 ;;
 @hits = grep overlap($_, $t, 4), @words;
 dd \@hits;
 ;;
 @hits = grep overlap($_, $t, 6), @words;
 dd \@hits;
 ;;
 @hits = grep overlap($_, $t, 7), @words;
 dd \@hits;
 ;;
 sub overlap {
   my ($s, $t, $min) = @_;
   ;;
   return ($s ^ $t) =~ m{ \A \x00{$min,} }xms;
   }
"
["hello", "hel", "help", "helper", "helping"]

["help", "helper", "helping"]

["helper"]

[]

[download]

In reply to Re: Searching for a string within an array using regex by AnomalousMonk
in thread Searching for a string within an array using regex by Aquilae

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