Just playing around a bit with some text and grep and running into a problem I can't understand. Hoping one of you can enlighten me to what I'm overlooking.

Given two arrays with elements that consist of 3 space delimited characters, I want to print out any elements from array two for which the first two characters match an element from array 1. If I use grep in a scalar context, I can get it to work:

my @data1 = ( "a 1 a", "a 2 T", "a 3 C" );
my @data2 = ( "a 2 Y", "a 3 R", "a 4 Q", "b 5 R" );

for ( @data2 ) {
    my ($match) = $_ =~ /^(\w\s+\d)/;
    if ( grep { /$match/ } @data1 ) {
            print  "$_\n";
    }
}

[download]
This correctly prints the result: 
$ perl compare.pl
a 2 Y
a 3 R

[download]

However, if I try to use grep in a list context, storing the matches in '@result', I only get the second match and not the first:

my @results;
for my $elem ( @data1 ) {
    my ($match) = $elem =~ /(\w\s+\d)/;
    @results = grep { /$match/ } @data2;
}
 print "$_\n" for @results;

[download]
$ perl compare.pl
a 3 R

[download]

What am I missing here? Why are both matches not being stored in @results?

In reply to Help understand why this grep does not work by drmrgd

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