delete an element from an array in php

Question

Ok then. I have a filled array defined like this:

$subs = array();
for (...) {
 // extracting of variables $knowledgeLevel, $name, $short, $long
 $subs [] = array (
 'knowledgeLevel' => $knowledgeLevel,
 'name' => $name,
 'shortTheory' => $short,
 'longTheory' => $long
 );
}

then I receive a value $kl, and I want to eventually delete from the array $subs the element that has the knowledgeLevel equal to $kl. I've tried to do so:

foreach ( $subs as $subject ) {
 if ($subject['knowledgeLevel'] == $kl) {
 unset ($subject);
 }
}

and so

foreach ( $subs as $subject ) {
 if ($subject['knowledgeLevel'] == $kl) {
 unset ($subject['knowledgeLevel']);
 unset ($subject['name']);
 unset ($subject['shortTheory']);
 unset ($subject['longTheory']);
 }
}

but these don't seem to work.

• Fabio: Where is $kl defined?
• user1823761: You want to remove an element from $subs array? It's a numeric array, not associative. Its elements are associative arrays.
• Jannuzzo: I have two functions that use the same array (declared as global). $klis the parameter of the second function
• Jannuzzo: @Mojtaba sorry! Edited

Answer 1

In order to be able to directly modify array elements within the loop precede $value with &. In that case the value will be assigned by reference.

Use & with foreach ( $subs as &$subject )

foreach ( $subs as &$subject ) 
 if ( $subject['knowledgeLevel'] == $kl ) 
 unset ($subject);

Or try this:

This form will additionally assign the current element's key to the $key variable on each iteration.

foreach ( $subs as $key => $subject )
 if ( $subject['knowledgeLevel'] == $kl ) 
 unset( $subs[$key] );

• Sina R.: there is no diffrent but I my self choose the second. because its clear.
• Sina R.: @Jannuzzo . welcome to stackoverflow. and let me remind you somthing. lets be a good supporter with upvoting and accepting useful answers.(-:
• Andrey Volk: @imsiso 'vote up' privilege requires 15 reputation. OP has only 6.
• Sina R.: @AndreyVolk I know but I say it not for now. for all time but he can still accept the answers. btw +1 to you.

Answer 2

$subject is not reference to $subs it's new variable and with unset($subject['anything']) you are not deleting anything from $subs

Use for loop:

for($i=0;$i<count($subs);$i++) {
 if ($subs[$i]['knowledgeLevel'] == $kl) {
 unset ($subs[$i]);
 }
}