[Israel.pm] why does upper-casing costs more than lower-casing?

[Nathan Abu]

Hi,

been wondering why does *uc* takes almost twice the time compared to *lc*?

code:

*#!/usr/bin/perl*
*use warnings;*
*use strict;*
*use Benchmark qw(cmpthese timethese :hireswallclock);*
*my $string  = 'Phone: 054-8765434 Email: nabu at lknhy4564.com 054-3232
888-22222 abdsx';*
*
*
*cmpthese(*
*    timethese(*
*        50_000_000,*
*        {   to_lower => sub { lc($string); },*
*            to_upper => sub { uc($string); }*
*        }*
*    )*
*)*
*
*
which results in:
*Benchmark: timing 50000000 iterations of to_lower, to_upper...*
*  to_lower: 8.45244 wallclock secs ( 8.45 usr + -0.00 sys =  8.45 CPU) @
5917159.76/s (n=50000000)*
*  to_upper: 15.321 wallclock secs (15.31 usr +  0.00 sys = 15.31 CPU) @
3265839.32/s (n=50000000)*
*              Rate to_upper to_lower*
*to_upper 3265839/s       --     -45%*
*to_lower 5917160/s      81% *
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