Eric Butera wrote:
On Thu, Mar 27, 2008 at 12:41 PM, Peter Ford <pete@xxxxxxxxxxxxx> wrote:
Jason Pruim wrote:
>
> On Mar 27, 2008, at 11:05 AM, Shawn McKenzie wrote:
>> Al wrote:
>>> Good point. I usually do use the single quotes, just happened to key
>>> doubles for the email.
>>>
>>> Actually, it's good idea for all variable assignments.
>>>
>>> Philip Thompson wrote:
>>>> On Mar 26, 2008, at 6:28 PM, Al wrote:
>>>>> Depends on the server and it's load. I've strung together some
>>>>> rather large html strings and they aways take far less time than the
>>>>> transient time on the internet. I used to use OB extensively until
>>>>> one day I took the time to measure the difference. I don't recall the
>>>>> numbers; but, I do recall it was not worth the slight extra trouble
>>>>> to use OB.
>>>>>
>>>>> Now, I simple assemble by html strings with $report .= "foo"; And
>>>>> then echo $report at the end. It also makes the code very easy to
>>>>> read and follow.
>>>>
>>>> You might as well take it a step further. Change the above to:
>>>>
>>>> $report .= 'foo';
>>>>
>>>> This way for literal strings, the PHP parser doesn't have to evaluate
>>>> this string to determine if anything needs to be translated (e.g.,
>>>> $report .= "I like to $foo"). A minimal speedup, but nonetheless...
>>>>
>>>> ~Philip
>>>>
>>>>
>>>>> Andrew Ballard wrote:
>>>>>> On Wed, Mar 26, 2008 at 1:18 PM, Al <news@xxxxxxxxxxxxx> wrote:
>>>>>>> You are really asking an HTML question, if you think about it.
>>>>>>>
>>>>>>> At the PHP level, either use output buffering or assemble all your
>>>>>>> html string as a variable and
>>>>>>> then echo it. The goal is to compress the string into the minimum
>>>>>>> number of packets.
>>>>>> Yes, but do so smartly. Excessive string concatenation can slow
>>>>>> things
>>>>>> down as well. On most pages you probably won't notice much
>>>>>> difference,
>>>>>> but I have seen instances where the difference was painfully obvious.
>>>>>> Andrew
>>
>> Yes and if your script takes .00000000000000000000000000000002 seconds
>> to run using double quotes it will only take
>> .000000000000000000000000000000019 seconds with single (depending upon
>> how many quotes you have of course) :-)
>
> I'm coming in late to this thread so sorry if I missed this :)
>
> How much of a difference would it make if you have something like this:
> echo "$foo bar bar bar bar $foo $foo"; verses: echo $foo . "bar bar bar
> bar" . $foo $foo; ?In other words... You have a large application which
> is most likely to be faster? :)
>
>
There was a discussion about this a few weeks ago - ISTR that the compiler does
wierd things with double-quoted strings, something like tokenising the words and
checking each bit for lurking variables.
So in fact
echo "$foo bar bar bar bar $foo $foo";
is slowest (because there *are* variables to interpolate,
echo $foo . " bar bar bar bar ".$foo." ".$foo;
is a bit faster, but the double-quoted bits cause some slow-down,
echo $foo . ' bar bar bar bar '.$foo.' '.$foo;
is a bit faster again - the single quoted bits pass through without further
inspection, and finally
echo $foo,' bar bar bar bar ',$foo,' ',$foo;
is actually the fastest, because the strings are not concatenated before output.
I think that was the overall summary - I can't locate the original post to
verify (or attribute) but it's in this list somewhere...
Cheers
--
Peter Ford phone: 01580 893333
Developer fax: 01580 893399
Justcroft International Ltd., Staplehurst, Kent
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Can you prove these statements with real benchmarks that are current?
Ilia said that it is a myth that there is a performance difference
between " and ' in one of his talks.
I found one recent post on the subject in gmane:
http://article.gmane.org/gmane.comp.php.general/169028
The poster's results are as I remembered, except that was building a string, not
echoing: possibly not quite the same.
So I tried it myself, adapting to using echo (to the ob to avaoid printing forty
million * "foo bar bar ..."). For an extra wheeze, I also tried <?=$foo?> syntax
embedded in HTML to see if that is as bad as people make out. I didn't try
HEREDOC syntax, because it is difficult to reproduce exactly the same output -
newlines get added to the output.
To get thing to run I needed to increase time out, and reduce the string to
avoid filling the PHP memory limit I have set at the moment. Here is the code:
<?php
ini_set('max_execution_time',300);
$foo = 'f';
ob_start();
$time[1] = microtime(TRUE);
for($x = 0; $x < 10000000; $x++){
echo "$foo b b b b $foo $foo";
}
$time[2] = microtime(TRUE);
ob_end_clean();
ob_start();
$time[3] = microtime(TRUE);
for($x = 0; $x < 10000000; $x++){
echo $foo . ' b b b b '.$foo.' '.$foo;
}
$time[4] = microtime(TRUE);
ob_end_clean();
ob_start();
$time[5] = microtime(TRUE);
for($x = 0; $x < 10000000; $x++){
echo $foo . " b b b b ".$foo." ".$foo;
}
$time[6] = microtime(TRUE);
ob_end_clean();
ob_start();
$time[7] = microtime(TRUE);
for($x = 0; $x < 10000000; $x++){
echo $foo,' b b b b ',$foo,' ',$foo;
}
$time[8] = microtime(TRUE);
ob_end_clean();
ob_start();
$time[9] = microtime(TRUE);
for($x = 0; $x < 10000000; $x++){
?><?=$foo?> b b b b <?=$foo?> <?=$foo?><?php
}
$time[10] = microtime(TRUE);
ob_end_clean();
echo 'For 10,000,000 loops:';
echo '<br />Interpolation:',($time[2]-$time[1]);
echo '<br />Concatenation single quote:',($time[6]-$time[5]);
echo '<br />Concatenation double quote:',($time[4]-$time[3]);
echo '<br />List:',($time[8]-$time[7]);
?>
The results are slightly different to what I expected:
For 10,000,000 loops:
Interpolation:13.385520935059
Concatenation single quote:14.523960828781
Concatenation double quote:14.472594976425
List:11.083581924438
Embedded in HTML:16.329668045044
So, it looks like for echoing at least then single quotes are actually
marginally slower than double quotes, and interpolation is faster.
Embedding in HTML *is* slower, and the comma-separated list syntax is fastest.
I suspect YMMV...
--
Peter Ford phone: 01580 893333
Developer fax: 01580 893399
Justcroft International Ltd., Staplehurst, Kent
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