How to check if a variable even exist after decode JSON? - php

Question

I have this JSON string.
[
{
"name": "user_title",
"value": "Bapak."
},
{
"name": "user_firstname",
"value": "Test"
},
{
"name": "user_lastname",
"value": "XXX"
}
]
This string generated dynamically. It may has more or less. I use JSON Decode to process it in PHP.
$json_form = json_decode($json_string,true);
$user_title = $json_form[0]['value'];
$user_firstname = $json_form[1]['value'];
$user_lastname = $json_form[2]['value'];
How do I check the variable user_title even exist in the string?
If it exist I should get the value but if not that means $user_title = NULL.

Answer 1

You might want to consider mapping your JSON into a key/value array using array_column; then it is easy to check for the existence of a value. For example:
$json_form = json_decode($json_string, true);
$values = array_column($json_form, 'value', 'name');
$user_title = $values['user_title'];
$user_firstname = $values['user_firstname'];
$user_lastname = $values['user_lastname'];
echo "title: $user_title\nfirst name: $user_firstname\nlast name: $user_lastname\n";
Output for your sample data is:
title: Bapak.
first name: Test
last name: XXX
It's also easy to add default values when a key is missing, for example:
$user_title = $values['user_title'] ?? '';