Consider the following test code:
<?php
$myArray = array();
for( $i = 0; $i <= 10000; $i++ )
{
$date = microtime( TRUE );
$key = rand( $date, $date * rand( 1, 5000 ));
$myArray[$key] = $key;
}
echo '$myArray items created: ' . count( $myArray ) . '<br><br>';
$startTime = microtime( TRUE );
$foundCount = 0;
for( $i = 0; $i <= 10000; $i++ )
{
$date = microtime( TRUE );
$key = rand( $date, $date * rand( 1, 5000 ));
if( array key exists( $key, $myArray ))
{
$foundCount++;
}
}
$endTime = microtime( TRUE );
echo 'array key exists took [' . ( $endTime - $startTime ) . '] seconds;
found: [' . $foundCount . '] keys<br><br>';
$startTime = microtime( TRUE );
$foundCount = 0;
for( $i = 0; $i <= 10000; $i++ )
{
$date = microtime( TRUE );
$key = rand( $date, $date * rand( 1, 5000 ));
if( isset( $myArray[$key] ))
{
$foundCount++;
}
}
$endTime = microtime( TRUE );
echo 'isset took [' . ( $endTime - $startTime ) . '] seconds; found: [' .
$foundCount . '] keys<br><br>';
$startTime = microtime( TRUE );
$foundCount = 0;
for( $i = 0; $i <= 10000; $i++ )
{
$date = microtime( TRUE );
$key = rand( $date, $date * rand( 1, 5000 ));
if( $myArray[$key] )
{
$foundCount++;
}
}
$endTime = microtime( TRUE );
echo 'IF() took [' . ( $endTime - $startTime ) . '] seconds; found: [' .
$foundCount . '] keys<br><br>';
?>
Running that I found that
if( isset( $myArray[$key] ))
is faster than
if( array key exists( $key, $myArray ))
is faster than
if( $myArray[$key] )
To be honest, I was surprised. I would have thought that if( $myArray[$key]
) would have been the fastest way to check. I'm wondering if those in the
know could explain why it's the slowest and also where the discrepancies
come from w/r/t the difference in the amount of time it takes to make each
check.
thnx,
Chris
