On Tue, 26 Sep 2006 21:45:58 +1000, David Tulloh wrote: > Google Kreme wrote: >> On 25 Sep 2006, at 06:11 , Sancar Saran wrote: >> ... >> >> If this is generating hundred of K of HTML, use ' instead of " >> >> (yes, it's faster). >> > > I've seen this stated several times and at first glance it seems to make > sense. The double quoted version has all the \n and related characters > that need to be handled. > > Except that php is a C program and uses the printf family of functions. > This means that all the single quoted strings actually have to be > converted to escaped versions of double quoted strings, so internally > '\n' becomes "\\n". > > You can see this in some benchmarks, I ran the following script and a > single quoted version from the command line. I ran each 10 times, > interleaved to try to balance changes in the system load. > > <?php > $str=""; > for($i=0; $i<10000000; $i++) > $str.="foo"; > ?> > > I found that the double quoted version averaged 5.5516 seconds against > the single quoted script of 5.5627. Which really goes to show that > while the double quoted version is faster the difference is almost > completely irrelevent. While we're at it (running benchmarks three times, varying amount of loops): Benchmarking with 100K loops Case 1 : 'Adding a 10-character single quoted string to a var' Time : 0.23s - 0.24s Case 2 : 'Adding a 10-character double quoted string to a var' Time : 0.23s - 0.24s Performance : Anywhere between Decreased 1.1% and Increased 26.7% This seems really funny to me, cause I was under the impression a single quoted string was faster... I remember benchmarking that before. ---------------------------------------- Benchmarking with 10K loops Case 1 : 'Adding a 100-character single quoted string to a var' Time : 0.03s - 0.08s Case 2 : 'Adding a 100-character double quoted string to a var' Time : 0.03s Performance : Anywhere between Increased 0.7% and Increased 66.9% Still funny... and numbers get higher, too. ---------------------------------------- Benchmarking with 1M loops Case 1 : 'Setting a var with a 100-character single quoted string' Time : 2.29s - 2.63s Case 2 : 'Setting a var with a 100-character double quoted string' Time : 2.53 - 2.78s Performance : Anywhere between Decreased 3.1% and Decreased 16.3% Now this is probably what I saw previously and what made me decide using single quotes where possible. ---------------------------------------- Benchmarking with 1M loops Case 1 : 'Setting a var with a 100-character single quoted string incl. a variable (concat)' Time : 3.59s - 4.07s Case 2 : 'Setting a var with a 100-character double quoted string incl. a variable' Time : 4.14s - 4.40s Performance : Anywhere between Decreased 8.2% - Decreased 19.2% Well, try not to use variables in a string, but concatenate it together. ---------------------------------------- Benchmarking with 1M loops Case 1 : 'Setting a var with a 100-character double quoted string incl. a variable (concat)' Time : 3.58s - 3.79s Case 2 : 'Setting a var with a 100-character double quoted string incl. a variable' Time : 4.12s - 5.24s Performance : Anywhere between Decreased 14.9% - Decreased 38.4% Same with using double quoted strings only... ---------------------------------------- Hey! It's coffee break already! Ivo -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
