Numbers\isMultipleOf()

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predicate returns Closure returns bool pure throws
number → (number → bool)
At a glance — Bind a multiplier; the returned predicate is true when the value is a whole multiple of it. Zero always returns false. Throws InvalidArgumentException on non-number input.

Creates a predicate Closure that returns true when the passed value is a whole multiple of the pre-defined number. Zero is treated as a non-multiple and always returns false — that is a deliberate behaviour of this constructor. 

/**
  * @param int|float $multiple The fixed multiple to test against.
  * @return Closure(int|float):bool
  * @throws InvalidArgumentException If $multiple is not int or float.
  */
Numbers\isMultipleOf($multiple): Closure

Returned Closure

When Numbers\isMultipleOf() is called, it returns the following Closure which can be used like a regular function.

/**
  * @param int|float $value
  * @return bool  True when ($value % $multiple === 0) and $value !== 0.
  * @throws InvalidArgumentException If $value is not int or float.
  */
$function (int|float $value): bool

Examples

Partial Application

This can be used to create a simple closure which can be used as a regular function. 

// Create a predicate that checks for multiples of 3.
$isMultipleOf3 = Numbers\isMultipleOf(3);

// Called as a function.
var_dump($isMultipleOf3(12));  // true
var_dump($isMultipleOf3(13));  // false
var_dump($isMultipleOf3(0));   // false — zero is never a multiple here

// Used in a higher order function.
$onlyMultiples = array_filter([1, 3, 5, 6, 7, 9, 11, 12], $isMultipleOf3);
print_r($onlyMultiples); // [3, 6, 9, 12]

Curried

This can be called inline using currying. 

var_dump(Numbers\isMultipleOf(2)(12)); // true

Inlined with Higher Order Function

If you are not planning on reusing the Closure created, you can just call it inline with a higher order function as its callable. 

$evens = array_filter([1, 2, 3, 4, 5, 6], Numbers\isMultipleOf(2));
print_r($evens); // [2, 4, 6]

Details

Numbers Functions

Releated Number predicate Functions