如何检查项目数组是否仅包含此项目？

Question

$items1 = ['apple', 'tree', 'juice'];
$items2 = ['apple', 'tree'];
$items3 = ['apple'];

// loop
If ($items[i].containsOnly['apple'])
{
  // do something..
}

In the simplified example above I want to get the array that matches the given item. Is there a method available similar to 'containsOnly'? Or what is the best way to do this?

Answer 1

Couple your logic with count:

function containsOnly($a, $v)
{
    return count($a) === 1 && array_values($a)[0] === $v; 
}

This will ensure that you have only one item and the value is equal to what you are searching for.

Note: The usage of array_values here is to reset all the indexes so we can ensure [0] is where the value will be. Instead of the array_values variation you can use in_array if you prefer that.