note 102652 added to function.is-array
| From: | magentix at gmail dot com | Date: | Sat, 26 Feb 2011 17:12:36 +0000 |
| Subject: | note 102652 added to function.is-array | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-177359@lists.php.net to get a copy of this message | ||
If you wanted to have 'pure' associative arrays,
you could filter out non-string keys and then compare the count of the original array with the count
of the filtered array.
<?php
// Only validates empty or completely associative arrays
function is_assoc ($arr) {
return (is_array($arr) && count(array_filter(array_keys($arr),'is_string')) ==
count($arr));
}
$a = '';
$b = 'z';
$c = array();
$d = array('x','y','z');
$e = array('x','y','zed'=>'z');
$f =
array('ex'=>'x','why'=>'y','zed'=>'z');
echo '$a: ' . ( (is_assoc($a)) ? 'true' : 'false' ) ."\n";
// False
echo '$b: ' . ( (is_assoc($b)) ? 'true' : 'false' ) ."\n";
// False
echo '$c: ' . ( (is_assoc($c)) ? 'true' : 'false' ) ."\n";
// True
echo '$d: ' . ( (is_assoc($d)) ? 'true' : 'false' ) ."\n";
// False
echo '$e: ' . ( (is_assoc($e)) ? 'true' : 'false' ) ."\n";
// False
echo '$f: ' . ( (is_assoc($f)) ? 'true' : 'false' ) ."\n";
// True
?>
I've tested the point of checking whether the array is empty first.
The overall result was a 200% speed increase when the array was indeed empty,
but an average 10% slow when it had elements inside.
<?php
/***********************************************************
* Benchmarks: checking for empty array vs. not checking *
***********************************************************/
// With empty check
function is_assoc ($arr) {
return (is_array($arr) && (!count($arr) ||
count(array_filter(array_keys($arr),'is_string')) == count($arr)));
}
function test_speed($arr) {
$t = microtime(true);
for($i = 0; $i < 100000; ++$i) is_assoc($arr);
return (microtime(true) - $t);
}
echo '$a: ' . test_speed($a) ."\n"; // 0.20597505569458
echo '$b: ' . test_speed($b) ."\n"; // 0.19199514389038
echo '$c: ' . test_speed($c) ."\n"; // 0.28803396224976
echo '$d: ' . test_speed($d) ."\n"; // 0.94685983657837
echo '$e: ' . test_speed($e) ."\n"; // 0.96698403358459
echo '$f: ' . test_speed($f) ."\n"; // 0.98052096366882
// Without empty check
function is_assoc_2 ($arr) {
return (is_array($arr) && count(array_filter(array_keys($arr),'is_string')) ==
count($arr));
}
function test_speed_2($arr) {
$t = microtime(true);
for($i = 0; $i < 100000; ++$i) is_assoc_2($arr);
return (microtime(true) - $t);
}
echo '$a: ' . test_speed_2($a) ."\n"; // 0.18811202049255 = FASTER: 91.3% of
is_assoc
echo '$b: ' . test_speed_2($b) ."\n"; // 0.18782901763916 = FASTER: 97.8% of
is_assoc
echo '$c: ' . test_speed_2($c) ."\n"; // 0.64437484741211 = SLOWER: 223.7% of
is_assoc
echo '$d: ' . test_speed_2($d) ."\n"; // 0.84632205963135 = FASTER: 89.4% of
is_assoc
echo '$e: ' . test_speed_2($e) ."\n"; // 0.86739897727966 = FASTER: 89.7% of
is_assoc
echo '$f: ' . test_speed_2($f) ."\n"; // 0.87963700294495 = FASTER: 89.7% of
is_assoc
?>
----
Server IP: 69.147.83.197
Probable Submitter: 91.177.149.48
----
Manual Page -- http://www.php.net/manual/en/function.is-array.php
Edit -- https://master.php.net/note/edit/102652
Del: integrated -- https://master.php.net/note/delete/102652/integrated
Del: useless -- https://master.php.net/note/delete/102652/useless
Del: bad code -- https://master.php.net/note/delete/102652/bad+code
Del: spam -- https://master.php.net/note/delete/102652/spam
Del: non-english -- https://master.php.net/note/delete/102652/non-english
Del: in docs -- https://master.php.net/note/delete/102652/in+docs
Del: other reasons-- https://master.php.net/note/delete/102652
Reject -- https://master.php.net/note/reject/102652
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