comment on

"In general" is misleading.

In the particular case where you've no variables in the string, sure, maybe, but it's not an interesting use case.

#!/usr/bin/perl
use strict;
use warnings;
use Benchmark ('cmpthese');
my $dqv = 0;
my $sqv = 0;

cmpthese(1000000, {
                 double => \&dq,
                 single => \&sq,
                });

sub dq {
  $dqv++;
  my $str = "see $dqv run                                             
+                                        and $dqv";
}

sub sq {
  $sqv++;
  my $str = 'see '.$dqv.' run                                         
+                                            and '.$dqv;
}
[download]

The difference is substantial, but only when you make perl work harder to find the variable, hence the extra spaces in the string.

            Rate double single
double  943396/s     --   -37%
single 1492537/s    58%     --
[download]

In reply to Re^2: Optimizing Perl Code - single versus double quotes really that important? by j0wal
in thread Optimizing Perl Code - single versus double quotes really that important? by MashMashy

Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
Want more info? How to link or How to display code and escape characters are good places to start.


There's more than one way to do things
	PerlMonks