键入检查所有数组元素

Question

Is there any simple way of checking if all elements of an array are instances of a specific type without looping all elements? Or at least an easy way to get all elements of type X from an array.

Answer 1

You cannot achieve this without checking all the array elements, but you can use built-in array functions to help you.

You can use array_filter to return an array. You need to supply your own callback function as the second argument to check for a specific type. This will check if the numbers of the array are even.

function even($var){
  return(!($var & 1));
}

// assuming $yourArr is an array containing integers.
$newArray = array_filter($yourArr, "even");
// will return an array with only even integers.

As per VolkerK's comment, as of PHP 5.3+ you can also pass in an anonymous function as your second argument. This is the equivalent as to the example above.

$newArray = array_filter($yourArr, function($x) { return 0===$x%2; } );