Which method is faster and saner [simple example]

[scwizard]

// Former method.
$temp = preg_split("/(\r?\n)/", $bigstring);
$temp_size = count($temp);
$n = 0;
while($n < $temp_size) {
$result[$temp[$n]] = $temp[$n + 1];
$n = $n + 2;
}

// Later method.
$temp = preg_split("/(\r?\n)/", $bigstring);
foreach(array_chunk($temp, 2) as $part){
$result[$part[0]] = $part[1];
}

 

To me it seems like the former is faster and saner, because it's similar to how I'd do it in C.

The later seems slower, because you convert array A into array B before it becomes array C.

 

However someone from ##php thought the former was slower and less sane, because "you're trying to optimize something php has already optimized for you, and you're doing it poorly."

[haku]

Run a benchmark on it. Put each example in a loop that goes many times (1000+), and calculate the amount of time it takes.

 

Let us know the answer.

[xyph]

I would GUESS the first one would be faster. A raw foreach will generally be faster than a for/while for iterating through an array, but the array_chunk will add extra memory requirements, and could be slow on it's own.

 

For huge arrays, I'd go with the former for sure.

For smaller arrays, I doubt there'd be enough difference to really matter...

[kicken]

My quick benchmarks seem to indicate the first one is faster, but only just barely.  I'm not sure how big your bigstring is, I tested using the contents of a 22MB file which is definitely a big string.  With such a big string a single run took a few seconds so I only ran it a few times rather than a few thousand.  Results:

Begin testing, num tests = 9

//Method 1
Total time: 27.806; tracked 1 points
Time track:
    Point: Method 1 end
        From start: 27.806
        From prev: 27.806

//Method 1(alt)
Total time: 3.093; tracked 1 points
Time track:
    Point: Method 1 (alt) end
        From start: 3.093
        From prev: 3.093


//Method 2
Total time: 28.880; tracked 1 points
Time track:
    Point: Method 2 ends
        From start: 28.880
        From prev: 28.880

//Method 2(alt)
Total time: 4.881; tracked 1 points
Time track:
    Point: Method 2 (alt) ends
        From start: 4.881
        From prev: 4.881

//Method 3
Total time: 3.474; tracked 1 points
Time track:
    Point: Method 3 ends
        From start: 3.474
        From prev: 3.474

 

Method 1(alt) and Method 2(alt) are the same as method 1 and 2, but using str_replace+explode rather than preg_split.  Method 3 is str_replace+explode and a for loop rather than the while loop.

 

<?php

require 'timer.php';
$bigstring = file_get_contents('bigstring');
$runCount=0;
$numTests=mt_rand(1,9);

echo "Begin testing, num tests = {$numTests}\r\n";
marktime(false, 'Method 1 begin');
for ($runCount=0; $runCount<$numTests; $runCount++){
unset($result);
$temp = preg_split("/(\r?\n)/", $bigstring);
$temp_size = count($temp);
$n = 0;
while($n < $temp_size) {
	$result[$temp[$n]] = $temp[$n + 1];
	$n = $n + 2;
}
}
marktime(true, 'Method 1 end');
echo "\r\n";

marktime(false, 'Method 1 (alt) begin');
for ($runCount=0; $runCount<$numTests; $runCount++){
unset($result);
$temp = explode("\n", str_replace(array("\r\n","\r"), "\n", $bigstring));
$temp_size = count($temp);
$n = 0;
while($n < $temp_size) {
	$result[$temp[$n]] = $temp[$n + 1];
	$n = $n + 2;
}
}
marktime(true, 'Method 1 (alt) end');
echo "\r\n";

markTime(false, 'Method 2 begin');
for ($runCount=0; $runCount<$numTests; $runCount++){
// Later method.
unset($result);
$temp = preg_split("/(\r?\n)/", $bigstring);
foreach(array_chunk($temp, 2) as $part){
	$result[$part[0]] = $part[1];
}
}
markTime(true, 'Method 2 ends');
echo "\r\n";

markTime(false, 'Method 2 (alt) begin');
for ($runCount=0; $runCount<$numTests; $runCount++){
// Later method.
unset($result);
$temp = explode("\n", str_replace(array("\r\n", "\r"), "\n", $bigstring));
foreach(array_chunk($temp, 2) as $part){
	$result[$part[0]] = $part[1];
}
}
markTime(true, 'Method 2 (alt) ends');
echo "\r\n";

marktime(false, 'Method 3 begin');
for ($runCount=0; $runCount<$numTests; $runCount++){
unset($result);
$temp = explode("\n", str_replace(array("\r\n","\r"), "\n", $bigstring));
for ($i=0,$len=count($temp); $i<$len; $i+=2){
	$result[$temp[$i]] = $temp[$i+1];
}
}
markTime(true, 'Method 3 ends');
echo "\r\n";

?>

 

[haku]

Good stuff!