How do I remove specific keys from Array? PHP

Question

I am trying to remove keys from array.

Here is what i get from printing print_r($cats);

Array
(
    [0] => <a href="/website/index.php/Category:All" title="Category:All">All</a> &gt; <a href="/website/index.php/Category:Computer_errors" title="Category:Computer errors">Computer errors</a> &gt; <a href="/website/index.php/Category:HTTP_status_codes" title="Category:HTTP status codes">HTTP status codes</a> &gt; <a href="/website/index.php/Category:Internet_terminology" title="Category:Internet terminology">Internet terminology</a> 
    [1] => 
<a href="/website/index.php/Category:Main" title="Category:Main">Main</a> 
)

I am trying to use this to remove "Main" category from the array

    function array_cleanup( $array, $todelete )
{
    foreach( $array as $key )
    {
        if ( in_array( $key[ 'Main' ], $todelete ) )
        unset( $array[ $key ] );

    }
    return $array;
}

$newarray = array_cleanup( $cats, array('Main') );

Just FYI I am new to PHP... obviously i see that i made mistakes, but i already tried out many things and they just don't seem to work

Gaurav · Accepted Answer · 2011-03-05 07:14:25Z

10

Main is not the element of array, its a part of a element of array

function array_cleanup( $array, $todelete )
{
    $cloneArray = $array;
    foreach( $cloneArray as $key => $value )
    {
        if (strpos($value, $todelete ) !== false)   
           unset( $array[ $key ] );     //$array[$key] = str_replace($toDelete, $replaceWith, $value) ;  // add one more argument $replaceWith to function 

    }
    return $array;
}

Edit:

with array

function array_cleanup( $array, $todelete )
    {
      foreach($todelete as $del){
        $cloneArray = $array;
        foreach( $cloneArray as $key => $value )
        {          
            if (strpos($value, $del ) !== false)   
               unset( $array[ $key ] );     //$array[$key] = str_replace($toDelete, $replaceWith, $value) ;  // add one more argument $replaceWith to function 

           }
    }
     return $array;
}

  $newarray = array_cleanup( $cats, array('Category:Main') );

edited Mar 5, 2011 at 7:14

answered Mar 5, 2011 at 6:19

Gaurav

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7 Comments

Explosion Pills Over a year ago

should be strpos($value, $toDelete) !== false

user585303 Over a year ago

I also get parser error on if (strpos($value, $toDelete )! == false)

Explosion Pills Over a year ago

You don't replace it at all. It's a function argument. You would call it with 'Category:Main', or whatever string you want filtered.

Gaurav Over a year ago

@user585303 : you can use str_replace(). php.net/manual/en/function.str-replace.php

Explosion Pills Over a year ago

should be ` !== false, not ! == false`

|

Steve Woodson · Accepted Answer · 2013-03-08 06:53:09Z

3

Wanted to note that while the accepted answer works there's a built in PHP function that handles this called array_filter. For this particular example it'd be something like:

public function arrayRemoveMain($var){
    if ( strpos( $var, "Category:Main" ) !== false ) { return false; }
    return true;
}

$newarray = array_filter( $cats, "arrayRemoveMain" );

Obviously there are many ways to do this, and the accepted answer may very well be the most ideal situation especially if there are a large number of $todelete options. With the built in array_filter I'm not aware of a way to pass additional parameters like $todelete so a new function would have to be created for each option.

answered Mar 8, 2013 at 6:53

Steve Woodson

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1 Comment

Harry Pehkonen Over a year ago

I'm with you! Functional programming should be more popular. Could even put the function right inside the brackets! Then, to add support for $todelete, you would create a closure with "use ($todelete)" right after the function parameters: $todelete="Category:Main"; $newarray = array_filter($cats, function($cat) use($todelete){ if...});

Felipe Neuhauss · Accepted Answer · 2017-05-17 14:28:48Z

0

It's easy.

$times = ['08:00' => '08:00','09:00' => '09:00','10:00' => '10:00'];
$timesReserved = ['08:00'];
$times = (function() use ($times, $timesReserved) {
        foreach($timesReserved as $time){
            unset($times[$time]);
        }
        return $times;
    })();

answered May 17, 2017 at 14:28

Felipe Neuhauss

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Comments

Robert Sinclair · Accepted Answer · 2017-08-16 01:26:58Z

The question is "how do I remove specific keys".. So here's an answer with array filter if you're looking to eliminate keys that contain a specific string, in our example if we want to eliminate anything that contains "alt_"

$arr = array(
"alt_1"=>"val", 
"alt_2" => "val", 
"good key" => "val"
);

function remove_alt($k) {
    if(strpos($k, "alt_") !== false) {
        # return false if there's an "alt_" (won't pass array_filter)
        return false;
    } else {
        # all good, return true (let it pass array_filter)
        return true;
    }

}

$new = array_filter($arr,"remove_alt",ARRAY_FILTER_USE_KEY);
                                        # ^ this tells the script to enable the usage of array keys!

This will return

array(""good key" => "val");

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