What executes faster?

[vmusic]

Hi which of the two code lines executes faster?

Line 1:
echo $tdac . $spgt . $song_info[2] . $es . $etdetr . "\n ";

Line 2:
echo " $tdac $spgt $song_info[2] $es $etdetr \n ";

Thanks,

SlowScript in Columbus

[larand]

Well, personally, I don't know. But it would simply be a matter of say running a loop of 100 or 1000 of the line and timing the execution of the script. Repeat the same thing for the second line that you have, then compare the two times.

That should give you your answer fairly easily...

[superwormy]

The first should.

But really, I can't think of a case where the difference woudl ever be anything but entirely negligable.

[procoder]

its a matter of neat code to me..

but im sure the difference is around 0.000001 secs

meaning it doest matter unless you do it 1 million times, and you loose a second(or less even, just a example)

[mcgruff]

Speed isn't an issue with either.

Anything less than 0.1s isn't going to make any noticable difference to page loads and I'd guess that either line is going to come in around hundredths or thousands of a second.

If you want to test scripts to get a feel for what is significant and what isn't there's a timer fuction in the php manual.

Personally I always concatenate vars and strings since it makes the code easier to read and avoids odd problems with vars inside double quoted strings.

[zacarias]

Not sure, but:

In the first example PHP has to concatenate the variables and only then it sends them out. That could make it slower.

A possible 3rd way:

echo $one, $two, $plus, $test;

Wich goes out without concatenating and avoids "" problems.

Originally posted by vmusic
Hi which of the two code lines executes faster?

Line 1:
echo $tdac . $spgt . $song_info[2] . $es . $etdetr . "\n ";


Line 2:
echo " $tdac $spgt $song_info[2] $es $etdetr \n ";

[sarahk]

I've put some speed tests up at http://property.digitalrice.com/tutorial/index.php?p=6#speed which might be of interest.

[laserlight]

I read an article some years back on this, I believe it was written or endorsed by one of the big names in PHP, perhaps Rasmus himself.

Basically, the conclusion was that variables within strings will be parsed slower than variables that are concatenated.

The idea here is that having to parse the string for variables and then expanding them takes additional time compared to simply joining the strings and variables.

I suspect that separating echo statements with commas will not make a difference from concatenation either, for a small number of concatenations/arguments.

[Weedpacket]

An earlier thread on this exact topic:
http://www.phpbuilder.com/board/showthread.php?s=&threadid=10207322&highlight=faster+strings

[sarahk]

Thanks for the link Weedpacket!

[mcgruff]

One thing I forgot to mention: IMHO it's better to build vars which are echo'd out in an html template (or perhaps use a template engine like smarty) rather than echoing out directly from php. This keeps the html presentation code separate from the php scripting.

In general think that good application design is the key issue on which to spend your time. Being over concerned with efficiency can lead you down a blind alley.

[Weedpacket]

Originally posted by mcgruff
In general think that good application design is the key issue on which to spend your time. Being over concerned with efficiency can lead you down a blind alley.

Donald Knuth
We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil.

And if it's good enough for Knuth, it's good enough for me.

[Weedpacket]

Originally posted by sarahk
I've put some speed tests up at http://property.digitalrice.com/tutorial/index.php?p=6#speed which might be of interest.

Ooh, neat!

[drawmack]

and if you really want to test your code - http://www.phpbuilder.com/snippet/detail.php?type=snippet&id=1016