JSON Search and remove in php?

Question

Hello!

I have a session variable $_SESSION["animals"] containing a deep json object with values:

$_SESSION["animals"]='{
"0":{"kind":"mammal","name":"Pussy the Cat","weight":"12kg","age":"5"},
"1":{"kind":"mammal","name":"Roxy the Dog","weight":"25kg","age":"8"},
"2":{"kind":"fish","name":"Piranha the Fish","weight":"1kg","age":"1"},
"3":{"kind":"bird","name":"Einstein the Parrot","weight":"0.5kg","age":"4"}
}'; 

For example, I want to find the line with "Piranha the Fish" and then remove it (and json_encode it again as it was). How to do this? I guess i need to search in json_decode($_SESSION["animals"],true) resulting array and find the parent key to remove but i'm stucked anyways.

Answer 1

json_decode will turn the JSON object into a PHP structure made up of nested arrays. Then you just need to loop through them and unset the one you don't want.

<?php
$animals = '{
 "0":{"kind":"mammal","name":"Pussy the Cat","weight":"12kg","age":"5"},
 "1":{"kind":"mammal","name":"Roxy the Dog","weight":"25kg","age":"8"},
 "2":{"kind":"fish","name":"Piranha the Fish","weight":"1kg","age":"1"},
 "3":{"kind":"bird","name":"Einstein the Parrot","weight":"0.5kg","age":"4"}
 }';

$animals = json_decode($animals, true);
foreach ($animals as $key => $value) {
    if (in_array('Piranha the Fish', $value)) {
        unset($animals[$key]);
    }
}
$animals = json_encode($animals);
?>

Answer 2

You have an extra comma at the end of the last element in your JSON. Remove it and json_decode will return an array. Simply loop through it, test for string, then unset the element when found.

If you need the final array reindexed, simply pass it to array_values.

Answer 3

This works for me:

#!/usr/bin/env php 
<?php

    function remove_json_row($json, $field, $to_find) {

        for($i = 0, $len = count($json); $i < $len; ++$i) {
            if ($json[$i][$field] === $to_find) {
                array_splice($json, $i, 1); 
            }   
        }   

        return $json;
    }   

    $animals =
'{
"0":{"kind":"mammal","name":"Pussy the Cat","weight":"12kg","age":"5"},
"1":{"kind":"mammal","name":"Roxy the Dog","weight":"25kg","age":"8"},
"2":{"kind":"fish","name":"Piranha the Fish","weight":"1kg","age":"1"},
"3":{"kind":"bird","name":"Einstein the Parrot","weight":"0.5kg","age":"4"}
}';

    $decoded = json_decode($animals, true);

    print_r($decoded);

    $decoded = remove_json_row($decoded, 'name', 'Piranha the Fish');

    print_r($decoded);

?>