Twig : Unset element from array - twig

Question

I have an array of elements composed of key => value for example:
arr = { 156 : 'one', 99 : 'tow' }
I want to remove an element from the array depending on the key. Like doing unset() in php ? Is it possible ?

Answer 1

You can also use the filter pipe like this:
{% set arr = arr | filter((v, k) => k != '99') %}

Answer 2

You can extend twig to do this
<?php
class Project_Twig_Extension extends \Twig\Extension\AbstractExtension {
public function getFunctions(){
return [
new \Twig\TwigFunction('unset', [$this, 'unset'], [ 'needs_context' => true, ]),
];
}
/**
* $context is a special array which hold all know variables inside
* If $key is not defined unset the whole variable inside context
* If $key is set test if $context[$variable] is defined if so unset $key inside multidimensional array
**/
public function unset(&$context, $variable, $key = null) {
if ($key === null) unset($context[$variable]);
else{
if (isset($context[$variable])) unset($context[$variable][$key]);
}
}
}
Usage inside twig:
<h1>Unset</h1>
{% set foo = 'bar' %}
{% set bar = { 'foo' : 'bar', } %}
<h2>Before</h2>
<table>
<tr>
<td>foo</td><td>{{ foo | default('not applicable') }}</td>
</tr>
<tr>
<td>bar.foo</td><td>{{ bar.foo | default('not applicable') }}</td>
</tr>
</table>
{% do unset('foo') %}
{% do unset('bar', 'foo') %}
<h2>After</h2>
<table>
<tr>
<td>foo</td><td>{{ foo | default('not applicable') }}</td>
</tr>
<tr>
<td>bar.foo</td><td>{{ bar.foo | default('not applicable') }}</td>
</tr>
</table>
output
Before
|------------------------------|------------------------------|
| foo | bar |
| bar.foo | bar |
|------------------------------|------------------------------|
After
|------------------------------|------------------------------|
| foo | not applicable |
| bar.foo | not applicable |
|------------------------------|------------------------------|