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Another small speed up can be achieved by replacing

```my \$leaps =  int( (\$y - 1970) / 4 + 0.5 );
((((\$y-1970)*365 +\$leaps+MONTHS->{\$m}+(\$d-1))*24 +\$H)*60 +\$M)*60 +
+\$S;

with

```(((int((\$y-1970)*365.25-.5)+MONTHS->{\$m}+\$d)*24 +\$H)*60 +\$M)*60 +\$S;

in my experiments between 5 to 10%. All other attempts using split and unpack are much slower. I found substr to be very fast:

```sub str2epoch3 {
(((int((substr(\$_,12,4)-1970)*365.25-.5)+
MONTHS->{substr(\$_,8,3)}+substr(\$_,5,2))*24 +substr(\$_,1
+7,2))*60 +
substr(\$_,20,2))*60 +substr(\$_,23,2);
}

about 60% faster than BrowserUk's code. I wonder whether there is something wrong...

Here is my full code:
```use strict;
use warnings;
use Benchmark qw/cmpthese/;

use constant MONTHS => { qw[
Jan 0 Feb 31 Mar 59 Apr 90 May 120 Jun 151
Jul 181 Aug 212 Sep 242 Oct 272 Nov 303 Dec 334
] };

sub str2epoch {
my( \$d, \$m, \$y, \$H, \$M, \$S ) = \$_ =~
m[^.... (\d\d) (...) (\d\d\d\d) (\d\d):(\d\d):(\d\d)]
my \$leaps =  int( (\$y - 1970) / 4 + 0.5 );
((((\$y-1970)*365 +\$leaps+MONTHS->{\$m}+(\$d-1))*24 +\$H)*60 +\$M)*60 +
+\$S;
}

sub str2epoch2 {
my( \$d, \$m, \$y, \$H, \$M, \$S ) = \$_ =~
m[^.... (\d\d) (...) (\d\d\d\d) (\d\d):(\d\d):(\d\d)]
(((int((\$y-1970)*365.25-.5)+MONTHS->{\$m}+\$d)*24 +\$H)*60 +\$M)*60 +\$
+S;
}

sub str2epoch3 {
(((int((substr(\$_,12,4)-1970)*365.25-.5)+
MONTHS->{substr(\$_,8,3)}+substr(\$_,5,2))*24 +substr(\$_
+,17,2))*60 +
substr(\$_,20,2))*60 +substr(\$_,23,2);
}

my \$str = 'Fri, 01 Mar 2013 01:21:14 +0000';

cmpthese( -3, {BrowserUK => sub { str2epoch (\$str) },
BUK2      => sub { str2epoch2(\$str) },
substr    => sub { str2epoch3(\$str) }, }
);

In reply to Re^2: High-speed Date Formatting by hdb
in thread *SOLVED* High-speed Date Formatting by Endless

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