Check if index in array exists from string

Question

do you know how to test, whether an index, based on what we pass in a string, exists in an array?

Assume the following code:

<?php

$myArray = [
    "elemOne" => "valueElemOne",
    "elemTwo" => [
        "elemTwoOne" => "valueElemTwoOne",
        "elemTwoTwo" => [
            "elemThreeOne" => "valueElemThreeOne",
            "elemThreeTwo" => "valueElemThreeTwo",
        ],
    ],
];

Now, I have a string $myString = "elemTwo/elemTwoTwo/elemThreeThree". What I want to do with $myString is somewhat format it in a way, so I could check

<?php

if(isset($myArray['elemTwo']['elemTwoTwo']['elemThreeThree'])) {
    // maybe do something
    return true;
} else {
    return false;
}

Naturally in my case this would return false, as the index "elemThreeThree" does not exist within my array. I tried splitting the string, tried to format as [elemTwo][elemTwoTwo][elemThreeThree] and then evaluating it, but nothing really worked.

Do you think of a possible approach that could help me?

donald123 · Accepted Answer · 2015-07-17 11:11:34Z

1

simple solution could be

  <?php
     $arr = array('hello'=>array('world'=>array('in'=>'jo')));
     $myString = "hello/world/inf";

     function checkString($string, array $search_array) {
        $test = explode('/',$string);
        foreach($test as $key) {
           if(isset($search_array[$key])) $search_array = $search_array[$key];
           else return false;
        }
        return true;
     }
     var_dump(checkString($myString,$arr));
     die;

The Output of the function will true or false

answered Jul 17, 2015 at 11:11

donald123

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Comments

Christian · Accepted Answer · 2015-07-17 11:08:56Z

0

Why did splitting it not work? Is there something wrong with this?

<?php
$arrayTest = array(
    "arrayOne" => "string", 
    "arrayTwo" => array(
        "arrayThree"    => "string",
        "arrayFour"     => array("winner" => "me")
    )
);

var_dump(expanded_key_exists($arrayTest, "arrayOne"));
var_dump(expanded_key_exists($arrayTest, "arrayTwo"));
var_dump(expanded_key_exists($arrayTest, "arrayTwo/arrayThree"));
var_dump(expanded_key_exists($arrayTest, "arrayTwo/arrayThree/arrayTwenty"));
var_dump(expanded_key_exists($arrayTest, "arrayTwo/arrayFour"));
var_dump(expanded_key_exists($arrayTest, "arrayTwo/arrayFour/winner"));

if(expanded_key_exists($arrayTest, "arrayTwo/arrayFour/winner")){
    echo "The winner is: " . expanded_array_key($arrayTest, "arrayTwo/arrayFour/winner");
}

function expanded_key_exists($array, $key){
    $arrayKeys = explode("/", $key);
    foreach($arrayKeys as $someKey){
        if(is_array($array) && array_key_exists($someKey, $array)){
            $array = $array[$someKey];
        }else{
            return false;
        }
    }
    return true;
}

function expanded_array_key($array, $key){
    $arrayKeys = explode("/", $key);
    foreach($arrayKeys as $someKey){
        if(is_array($array) && array_key_exists($someKey, $array)){
            $array = $array[$someKey];
        }else{
            return null;
        }
    }
    return $array;
}
?>

answered Jul 17, 2015 at 11:08

Christian

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2 Comments

Christian Over a year ago

The output btw: bool(true) bool(true) bool(true) bool(false) bool(true) bool(true) The winner is: me

Andrew Over a year ago

Thanks a lot Christian I could not wrap my head around the problem.

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