[SOLVED] Advanced array removal and looping

[Dale_G]

Say I have this array

 

$aych = array( 'B', 'B', 'A', 'A', 'B', 'A', 'A', 'B', 'B', 'A' );

 

and when i do a print_r right now i get...

 

Array ( [0] => B [1] => B [2] => A [3] => A [4] => B [5] => A [6] => A [7] => B [8] => B [9] => A )

 

now what i need to happen is, loop through ALL keys in the array and check if there values are B, if they are, then remove it from the array and shift everything forward.

 

foreach ( $aych as $key => $value )
{
if ( preg_match( '{B}', $value ) )
{		
	array_splice( $aych, $value, 0 );
}
}

 

i was able to loop through them all, and check if the value is B, as shown above. I know you use the array_splice function for this, but im not exactly sure how to properly utilize this in this environment.

 

in the end, if i print_r it, i need to get

 

Array ( [0] => A [1] => A [2] => A [3] => A [4] => A )

 

which is after all of the B's are removed and the array moved foward. does anyone know how to do this?

 

 

[cooldude832]

look at using

 

http://us.php.net/manual/en/function.array-filter.php

 

with a callback function to filter out "B"

 

then to get then indexing back (which I don't know why u need to) try sorting it by key

[gevans]

foreach($aych as $key => $value)
{
if ($value === 'B'){
array_splice($aych, $key, 1);
}
}

 

Not tested, but should work

[Dale_G]

Not having much luck with array_filter, and gevans after trying your code after a print_r I get

 

Array ( [0] => A )

[corbin]

<?php

$aych = array( 'B', 'B', 'A', 'A', 'B', 'A', 'A', 'B', 'B', 'A' );


function RemoveB($c) {
return ($c == 'B');
}

$a = array_filter($aych, "RemoveB");
sort($a);
print_r($a);

 

 

The sort was just to redo the keys.  It would probably be faster to redo them manually though.  It would be even faster to do this (most likely):

 

$new_array = array();
foreach($aych as $c) {
    if($c != 'B') $aych[] = $c;
}

[gevans]

$aych = array( 'B', 'B', 'A', 'A', 'B', 'A', 'A', 'B', 'B', 'A' );
print_r($aych);
foreach($aych as $key => $value){
   if($value !== 'B'){
      $aych2[] = $value;
   }
}
echo '<br /><br />';
print_r($aych2);

 

try that instead, tested and working

[genericnumber1]

<?php
$array = array( 'B', 'B', 'A', 'A', 'B', 'A', 'A', 'B', 'B', 'A' );
$keys = array_keys($array, 'B');
foreach($keys as $key) {
unset($array[$key]);
}
$array = array_values($array);

print_r($array);
?>

 

Another solution. I tried for efficiency (let C do most of the looping, don't append to arrays as its speed can be unpredictable, and save the renumbering for the end)... it benchmarked about twice as fast as corbin's/gevans's second suggestion, but it's just a matter of fractions of microseconds... (pretty much nothing)

 

I'd go for readability, whichever one you find most readable I'd use.

[gevans]

I hadn't thought of that, I'd go with genericnumber1's solution. I always like to go with the fastest option!

[Dale_G]

Alright, thank all three of you for a job well done!