This function returns a new array that is the filtered version of the given array (or a range of it).
You supply a Predicate Method which runs for all elements in the array. It should return either true or false based on a condition.
Elements for which the predicate function returns true are included in the returned array, and ones that get false are ignored.
By default the function checks the whole array. You can optionally supply Offset And Length arguments to check a part of the array, traversing the array forward or backward.
Predicate FunctionPredicate Function
This function takes a Predicate Method that operates on the given array. The predicate function is passed the following arguments:
function(element, index);
| Argument | Type | Description |
|---|---|---|
| element | Any | The current array element's value |
| index | Real | The current array index |
The predicate function should return a Boolean, which affects how the original function modifies or reads the array.
See information and examples on Predicate Method.
NOTE See array_copy_while which is similar, but stops execution after the first false return of the predicate function.
array_filter(array, function, [offset], [length]);
| Argument | Type | Description |
|---|---|---|
| array | Array | The array to use |
| function | Function | The Predicate Method to run on each element |
| offset | Real | OPTIONAL The offset, or starting index, in the array. Setting a negative value will count from the end of the array. The starting index will then be array_length(array) + offset. See: Offset And Length |
| length | Real | OPTIONAL The number of elements to traverse. A negative value will traverse the array backwards (i.e. in descending order of indices, e.g. 2, 1, 0 instead of 2, 3, 4). See: Offset And Length |
function passed_the_test(element, index)
{
return element >= 50;
}
scores = [0, 15, 4, 78, 96, 65, 49];
passed = array_filter(scores, passed_the_test);
The above code first defines a function passed_the_test that takes in element and index parameters, which is usual for array predicate functions.
The function returns true if the value of element is greater than or equal to 50, otherwise it returns false.
It then creates an array scores with various values between 0 and 100. Finally it calls array_filter on this array and stores the new array in a variable passed.
The passed array would only contain values from the scores array that were greater than or equal to 50, satisfying the condition set in the predicate function.