To deliver the same result (i. e. undef) for not found input values, the tr solution has to be a bit more elaborate.

Somewhat along the line of

my $found = (my $pat = substr($0,0,1)) =~ tr/abcd/-=~^/;
$pat = $found ? $pat : undef;

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In reply to Re^2: Interesting line which I read from Monk's snippets by pKai
in thread Interesting line which I read from Monk's snippets by jesuashok

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