http://www.perlmonks.org?node_id=427189


in reply to To Single Quote or to Double Quote

Here's a benchmark, comparing the difference between a double quoted string, and a single quoted string:
#!/usr/bin/perl use strict; use warnings; use Benchmark("cmpthese"); cmpthese(-1, { "double", q !eval q {$a = "this is a string"}!, 'single', q !eval q {$b = 'this is a string'}!, });
And the results:
Rate single double single 34133/s -- -1% double 34462/s 1% --
Now, before you think double quotes are faster, the results of another run:
Rate double single double 33810/s -- -0% single 33811/s 0% --
When I ran this 10 times, double quotes won 5 times, single quotes won 4 times, and there was one tie. The difference was never more than 1%.

So my conclusion, on this single benchmark, is, performance wise, it doesn't matter. If you still want to claim there's a performance difference, come with either a better benchmark, or a discussion of the code of perl that shows there's a difference.