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Given this PHP array:
$options['systems'] = array(1, 2, 3)
How would I append the value 4 to the $systems array within the $options array?
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You could use array_push to push additional items like so:
array_push($options['systems'], 4);
Or the shorthand version:
$options['systems'][] = 4;
You can use php array_push function. Like this. array_push($options['systems'],4);
you can read the detail of array_push from below link.array_push manual