ArrayUtils Class Reference

A collection of static methods to play with arrays. More...

Static Public Member Functions
static	arrayDiffAssocRecursive ( $array1,... $arrays)
	Do array_diff_assoc() on multi-dimensional arrays.
static	cartesianProduct (... $inputArrays)
	Make an array consisting of every combination of the elements of the input arrays.
static	consistentHashSort (&$array, $key, $separator="\000")
	Sort the given array in a pseudo-random order which depends only on the given key and each element value in $array.
static	findLowerBound ( $valueCallback, $valueCount, $comparisonCallback, $target)
	Do a binary search, and return the index of the largest item that sorts less than or equal to the target value.
static	pickRandom ( $weights)
	Given an array of non-normalised probabilities, this function will select an element and return the appropriate key.

Detailed Description

A collection of static methods to play with arrays.

Since

1.21

Definition at line 28 of file ArrayUtils.php.

Member Function Documentation

arrayDiffAssocRecursive()

static ArrayUtils::arrayDiffAssocRecursive (   $array1,   $arrays  )

static

Do array_diff_assoc() on multi-dimensional arrays.

Note: empty arrays are removed.

Since

1.23

Parameters

array	$array1	The array to compare from
	array	...$arrays More arrays to compare against

Returns

array An array containing all the values from array1 that are not present in any of the other arrays.

Definition at line 158 of file ArrayUtils.php.

References $args.

cartesianProduct()

static ArrayUtils::cartesianProduct (   $inputArrays )

static

Make an array consisting of every combination of the elements of the input arrays.

Each element of the output array is an array with a number of elements equal to the number of input parameters.

In mathematical terms, this is an n-ary Cartesian product.

For example, ArrayUtils::cartesianProduct( [ 1, 2 ], [ 'a', 'b' ] ) produces [ [ 1, 'a' ], [ 1, 'b' ], [ 2, 'a' ], [ 2, 'b' ] ]

If any of the input arrays is empty, the result is the empty array []. This is in keeping with the mathematical definition.

If no parameters are given, the result is also the empty array.

The array keys are ignored. This implementation uses the internal pointers of the input arrays to keep track of the current position without referring to the keys.

Since

1.34.3

Parameters

array

...$inputArrays

Returns

array

Definition at line 210 of file ArrayUtils.php.

consistentHashSort()

static ArrayUtils::consistentHashSort ( &  $array,   $key,   $separator = "\000"  )

static

Sort the given array in a pseudo-random order which depends only on the given key and each element value in $array.

This is typically used for load balancing between servers each with a local cache.

Keys are preserved. The input array is modified in place.

Note: Benchmarking on PHP 5.3 and 5.4 indicates that for small strings, md5() is only 10% slower than hash('joaat',...) etc., since the function call overhead dominates. So there's not much justification for breaking compatibility with installations compiled with ./configure –disable-hash.

Parameters

array	&$array	Array to sort
string	$key
string	$separator	A separator used to delimit the array elements and the key. This can be chosen to provide backwards compatibility with various consistent hash implementations that existed before this function was introduced.

Definition at line 49 of file ArrayUtils.php.

References $hashes.

findLowerBound()

static ArrayUtils::findLowerBound (   $valueCallback,   $valueCount,   $comparisonCallback,   $target  )

static

Do a binary search, and return the index of the largest item that sorts less than or equal to the target value.

Since

1.23

Parameters

callable	$valueCallback	A function to call to get the value with a given array index.
int	$valueCount	The number of items accessible via $valueCallback, indexed from 0 to $valueCount - 1
callable	$comparisonCallback	A callback to compare two values, returning -1, 0 or 1 in the style of strcmp().
string	$target	The target value to find.

Returns

int|bool The item index of the lower bound, or false if the target value sorts before all items.

Definition at line 112 of file ArrayUtils.php.

pickRandom()

static ArrayUtils::pickRandom (   $weights )

static

Given an array of non-normalised probabilities, this function will select an element and return the appropriate key.

Parameters

array

$weights

Returns

bool|int|string

Definition at line 66 of file ArrayUtils.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\getRandomNonLagged(), Wikimedia\Rdbms\LoadBalancer\pickReaderIndex(), and Wikimedia\Rdbms\LoadBalancer\waitForOne().

---

The documentation for this class was generated from the following file:

• includes/libs/ArrayUtils.php