use strict;
use warnings;
use diagnostics;

my @list = (["qwe", 1], ["qwer", 2], ["tyui", 3], ["asdf", 4], ["ghjk"
+, 5], ["zxcv", 6] );
for my $item ("qwe", "qwer", "tyu", "yui", "tyui") {
    print grep($_->[0] ~~ /^$item$/, @list) . " " . $item . "\n";
}
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Though of course if you check for equality, you can also write grep($_->[0] eq $item, @list)