php extract sub array with specific key

Question

if i have the following array:

array(
   'var1' => 123,
   'var2' => 234,
   'var3' => 345
);

I would like to extract specific parts of this to build a new array i.e. var1 and var3.

The result i would be looking for is:

array(
   'var1' => 123,
   'var3' => 345
);

The example posted is very stripped down, in reality the array has a much larger number of keys and I am looking to extract a larger number of key and also some keys may or may not be present.

Is there a built in php function to do this?

Edit:

The keys to be extracted will be hardcoded as an array in the class i..e $this->keysToExtract

I dont understand completely. Can you explain what you mean by the criteria? — Marty Wallace
– Marty Wallace, Commented Jul 10, 2013 at 22:10
Well, what makes you choose var1 and var2 or is it random? Does it come from another array? Why are you choosing those 2 keys is my question. — elclanrs
– elclanrs, Commented Jul 10, 2013 at 22:11

Wrikken · Accepted Answer · 2013-07-10 22:16:21Z

5

$result = array_intersect_key($yourarray,array_flip(array('var1','var3')));

So, with your edit:

$result = array_intersect_key($yourarray,array_flip($this->keysToExtract));

edited Jul 10, 2013 at 22:16

answered Jul 10, 2013 at 22:11

Wrikken

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Comments

Dany Caissy · Accepted Answer · 2013-07-10 22:10:50Z

0

You don't need a built in function to do this, try this :

$this->keysToExtract = array('var1', 'var3'); // The keys you wish to transfer to the new array

// For each record in your initial array
foreach ($firstArray as $key => $value)
{
    // If the key (ex : 'var1') is part of the desired keys
    if (in_array($key, $this->keysToExtract)
    {
        $finalArray[$key] = $value; // Add to the new array
    }
}

var_dump($finalArray);

Note that this is most likely the most efficient way to do this.

answered Jul 10, 2013 at 22:10

Dany Caissy

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