Win8 Strawberry 5.30.3.1 (64) Sat 09/26/2020 11:37:04 C:\@Work\Perl\monks >perl use strict; use warnings; my $kards; my $bad = 'AKQJT98765432KKKK'; my $card = 'K'; my $e_string = "$kards = $bad =~ tr/$card//"; # print "e_string: >$e_string< \n"; # for debug eval $e_string; print "1: Num of '$card' in $bad is == $kards \n"; my $kings = $bad =~ tr/K//; print "2: Num of '$card' in $bad is == $kings \n"; __END__ Use of uninitialized value $kards in concatenation (.) or string at - line 8. Use of uninitialized value $kards in concatenation (.) or string at - line 12. 1: Num of 'K' in AKQJT98765432KKKK is == 2: Num of 'K' in AKQJT98765432KKKK is == 5