PHP Recursively unset array keys if match

Question

I have the following array that I need to recursively loop through and remove any child arrays that have the key 'fields'. I have tried array filter but I am having trouble getting any of it to work.

$myarray = array(
    'Item' => array(
        'fields' => array('id', 'name'),
        'Part' => array(
            'fields' => array('part_number', 'part_name')
        )
    ),
    'Owner' => array(
        'fields' => array('id', 'name', 'active'),
        'Company' => array(
            'fields' => array('id', 'name',),
            'Locations' => array(
                'fields' => array('id', 'name', 'address', 'zip'),
                'State' => array(
                    'fields' => array('id', 'name')
                )
            )
        )
    )    
);

This is how I need it the result to look like:

$myarray = array(
    'Item' => array(
        'Part' => array(
        )
    ),
    'Owner' => array(
        'Company' => array(
            'Locations' => array(
                'State' => array(
                )
            )
        )
    )    
);

What value will "Part" have after the remove action?

powtac
– powtac

2009-11-10 15:41:51 +00:00
Commented Nov 10, 2009 at 15:41 — powtac
– powtac, Commented Nov 10, 2009 at 15:41
I just need to unset 'fields' and leave part as 'array()'

SonnyBurnette
– SonnyBurnette

2009-11-10 15:44:26 +00:00
Commented Nov 10, 2009 at 15:44 — SonnyBurnette
– SonnyBurnette, Commented Nov 10, 2009 at 15:44

Darryl Hein · Accepted Answer · 2011-07-29 21:53:38Z

45

If you want to operate recursively, you need to pass the array as a reference, otherwise you do a lot of unnecessarily copying:

function recursive_unset(&$array, $unwanted_key) {
    unset($array[$unwanted_key]);
    foreach ($array as &$value) {
        if (is_array($value)) {
            recursive_unset($value, $unwanted_key);
        }
    }
}

edited Jul 29, 2011 at 21:53

Darryl Hein

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answered Nov 10, 2009 at 15:43

soulmerge

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2 Comments

Gerbus Over a year ago

I'm not sure this is correct. From the php manual: If a variable that is PASSED BY REFERENCE is unset() inside of a function, only the local variable is destroyed. The variable in the calling environment will retain the same value as before unset() was called. php.net/manual/en/function.unset.php

soulmerge Over a year ago

@Gerbus: That statement only applies to the variable itself, not its values (or array-keys in this case). Altering the array itself does not invalidate the reference to the passed array. In other words: You would be correct if the code contained unset($array);, but this code unsets an array key.

user187291 · Accepted Answer · 2009-11-10 16:25:24Z

5

you want array_walk

function remove_key(&$a) {
   if(is_array($a)) {
        unset($a['fields']);
        array_walk($a, __FUNCTION__);
   }
}
remove_key($myarray);

answered Nov 10, 2009 at 16:25

user187291

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3 Comments

greatwitenorth Over a year ago

Doesn't array_walk state that if you unset an element that the “behavior of this function is undefined, and unpredictable”?

Aaron Over a year ago

@greatwitenorth, it does say that. This might work, but its probably best to avoid it sadly.

Sergiu Z Over a year ago

doesn't work in php 7 as passing by reference has been deprecated

inakiabt · Accepted Answer · 2009-11-10 15:46:58Z

2

My suggestion:

function removeKey(&$array, $key)
{
    if (is_array($array))
    {
        if (isset($array[$key]))
        {
            unset($array[$key]);
        }
        if (count($array) > 0)
        {
            foreach ($array as $k => $arr)
            {
                removeKey($array[$k], $key);
            }
        }
    }
}

removeKey($myarray, 'Part');

answered Nov 10, 2009 at 15:46

inakiabt

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2 Comments

Michał Fraś Over a year ago

isset is not best at this case, should use array_key_exists <?php $a = ['key' => null]; var_dump(isset($a['key'])); //returns false var_dump(array_key_exists('key', $a)); //returns true

aProgger Over a year ago

Just a note for someone who stumbles across this: You dont need to check for isset before unset. unset does nothing if var is not set. You dont need to count an array before foreach. foreach does nothing if array is empty.

josesalomon · Accepted Answer · 2013-03-07 01:20:19Z

2

function recursive_unset(&$array, $unwanted_key) {

    if (!is_array($array) || empty($unwanted_key)) 
         return false;

    unset($array[$unwanted_key]);

    foreach ($array as &$value) {
        if (is_array($value)) {
            recursive_unset($value, $unwanted_key);
        }
    }
}

edited Mar 7, 2013 at 1:20

answered Jan 8, 2011 at 2:53

josesalomon

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Comments

artlung · Accepted Answer · 2009-11-10 15:52:17Z

1

function sanitize($arr) {
    if (is_array($arr)) {
        $out = array();
        foreach ($arr as $key => $val) {
            if ($key != 'fields') {
                $out[$key] = sanitize($val);
            }
        }
    } else {
        return $arr;
    }
    return $out;
}

$myarray = sanitize($myarray);

Result:

array (
  'Item' => 
  array (
    'Part' => 
    array (
    ),
  ),
  'Owner' => 
  array (
    'Company' => 
    array (
      'Locations' => 
      array (
        'State' => 
        array (
        ),
      ),
    ),
  ),
)

answered Nov 10, 2009 at 15:52

artlung

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Comments

Timo Huovinen · Accepted Answer · 2014-04-30 17:50:44Z

1

function removeRecursive($haystack,$needle){
    if(is_array($haystack)) {
        unset($haystack[$needle]);
        foreach ($haystack as $k=>$value) {
            $haystack[$k] = removeRecursive($value,$needle);
        }
    }
    return $haystack;
}

$new = removeRecursive($old,'key');

edited Apr 30, 2014 at 17:50

answered Apr 19, 2012 at 16:55

Timo Huovinen

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Comments

itsazzad · Accepted Answer · 2016-05-06 22:05:26Z

Code:

$sweet = array('a' => 'apple', 'b' => 'banana');
$fruits = array('sweet' => $sweet, 'sour' => $sweet);

function recursive_array_except(&$array, $except)
{
  foreach($array as $key => $value){
    if(in_array($key, $except, true)){
      unset($array[$key]);
    }else{
      if(is_array($value)){
        recursive_array_except($array[$key], $except);
      }
    }
  }
  return;
}

recursive_array_except($fruits, array('a'));
print_r($fruits);

Input:

Array
(
    [sweet] => Array
        (
            [a] => apple
            [b] => banana
        )

    [sour] => Array
        (
            [a] => apple
            [b] => banana
        )

)

Output:

Array
(
    [sweet] => Array
        (
            [b] => banana
        )

    [sour] => Array
        (
            [b] => banana
        )

)

Zaid Bin Khalid · Accepted Answer · 2019-04-18 07:48:50Z

1

I come up with a simple function that you can use to delete multiple array element based on multiple keys.

Detail example here.

Just a little change in code.

function removeRecursive($inputArray,$delKey){
    if(is_array($inputArray)){
        $moreKey    =   explode(",",$delKey);
        foreach($moreKey as $nKey){
            unset($inputArray[$nKey]);
            foreach($inputArray as $k=>$value) {
                $inputArray[$k] = removeRecursive($value,$nKey);
            }
        }
    }
    return $inputArray;
}

$inputNew   =   removeRecursive($input,'keyOne,keyTwo');

print"<pre>";
print_r($inputNew);
print"</pre>";

answered Apr 18, 2019 at 7:48

Zaid Bin Khalid

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Comments

Travis · Accepted Answer · 2009-11-10 15:43:27Z

0

Give this function a shot. It will remove the keys with 'fields' and leave the rest of the array.

function unsetFields($myarray) {
    if (isset($myarray['fields']))
        unset($myarray['fields']);
    foreach ($myarray as $key => $value)
        $myarray[$key] = unsetFields($value);
    return $myarray;
}

answered Nov 10, 2009 at 15:43

Travis

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Comments

cletus · Accepted Answer · 2009-11-10 15:48:43Z

-1

Recursively walk the array (by reference) and unset the relevant keys.

clear_fields($myarray);
print_r($myarray);

function clear_fields(&$parent) {
  unset($parent['fields']);
  foreach ($parent as $k => &$v) {
    if (is_array($v)) {
      clear_fields($v);
    }
  }
}

answered Nov 10, 2009 at 15:48

cletus

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Comments

Andy Gee · Accepted Answer · 2016-02-20 11:45:50Z

-1

I needed to have a little more granularity in unsetting arrays and I came up with this - with the evil eval and other dirty tricks.

$post = array(); //some huge array

function array_unset(&$arr,$path){
    $str = 'unset($arr[\''.implode('\'][\'',explode('/', $path)).'\']);';
    eval($str);
}

$junk = array();
$junk[] = 'property_meta/_edit_lock';
$junk[] = 'property_terms/post_tag';
$junk[] = 'property_terms/property-type/0/term_id';
foreach($junk as $path){
    array_unset($post,$path);
}

// unset($arr['property_meta']['_edit_lock']);
// unset($arr['property_terms']['post_tag']);
// unset($arr['property_terms']['property-type']['0']['term_id']);

answered Feb 20, 2016 at 11:45

Andy Gee

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