array_unique(3) [php man page]
ARRAY_UNIQUE(3) 1 ARRAY_UNIQUE(3) array_unique - Removes duplicate values from an array SYNOPSIS
array array_unique (array $array, [int $sort_flags = SORT_STRING]) DESCRIPTION
Takes an input $array and returns a new array without duplicate values. Note that keys are preserved. array_unique(3) sorts the values treated as string at first, then will keep the first key encountered for every value, and ignore all following keys. It does not mean that the key of the first related value from the unsorted $array will be kept. Note Two elements are considered equal if and only if (string) $elem1 === (string) $elem2 i.e. when the string representation is the same, the first element will be used. PARAMETERS
o $array - The input array. o $sort_flags - The optional second parameter $sort_flags may be used to modify the sorting behavior using these values: Sorting type flags: o SORT_REGULAR - compare items normally (don't change types) o SORT_NUMERIC - compare items numerically o SORT_STRING - compare items as strings o SORT_LOCALE_STRING - compare items as strings, based on the current locale. RETURN VALUES
Returns the filtered array. CHANGELOG
+--------+---------------------------------------------------+ |Version | | | | | | | Description | | | | +--------+---------------------------------------------------+ |5.2.10 | | | | | | | Changed the default value of $sort_flags back to | | | SORT_STRING. | | | | | 5.2.9 | | | | | | | Added the optional $sort_flags defaulting to | | | SORT_REGULAR. Prior to 5.2.9, this function used | | | to sort the array with SORT_STRING internally. | | | | +--------+---------------------------------------------------+ EXAMPLES
Example #1 array_unique(3) example <?php $input = array("a" => "green", "red", "b" => "green", "blue", "red"); $result = array_unique($input); print_r($result); ?> The above example will output: Array ( [a] => green [0] => red [1] => blue ) Example #2 array_unique(3) and types <?php $input = array(4, "4", "3", 4, 3, "3"); $result = array_unique($input); var_dump($result); ?> The above example will output: array(2) { [0] => int(4) [2] => string(1) "3" } SEE ALSO
array_count_values(3). NOTES
Note Note that array_unique(3) is not intended to work on multi dimensional arrays. PHP Documentation Group ARRAY_UNIQUE(3)
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ARRAY_MULTISORT(3) 1 ARRAY_MULTISORT(3) array_multisort - Sort multiple or multi-dimensional arrays SYNOPSIS
bool array_multisort (array &$array1, [mixed $array1_sort_order = SORT_ASC], [mixed $array1_sort_flags = SORT_REGULAR], [mixed $...]) DESCRIPTION
array_multisort(3) can be used to sort several arrays at once, or a multi-dimensional array by one or more dimensions. Associative ( string) keys will be maintained, but numeric keys will be re-indexed. PARAMETERS
o $array1 - An array being sorted. o $array1_sort_order - The order used to sort the previous array argument. Either SORT_ASC to sort ascendingly or SORT_DESC to sort descendingly. This argument can be swapped with $array1_sort_flags or omitted entirely, in which case SORT_ASC is assumed. o $array1_sort_flags - Sort options for the previous array argument: Sorting type flags: o SORT_REGULAR - compare items normally (don't change types) o SORT_NUMERIC - compare items numerically o SORT_STRING - compare items as strings o SORT_LOCALE_STRING - compare items as strings, based on the current locale. It uses the locale, which can be changed using setlocale(3) o SORT_NATURAL - compare items as strings using "natural ordering" like natsort(3) o SORT_FLAG_CASE - can be combined (bitwise OR) with SORT_STRING or SORT_NATURAL to sort strings case-insensitively This argument can be swapped with $array1_sort_order or omitted entirely, in which case SORT_REGULAR is assumed. o $... - More arrays, optionally followed by sort order and flags. Only elements corresponding to equivalent elements in previous arrays are compared. In other words, the sort is lexicographical. RETURN VALUES
Returns TRUE on success or FALSE on failure. CHANGELOG
+--------+---------------------------------------------------+ |Version | | | | | | | Description | | | | +--------+---------------------------------------------------+ | 5.4.0 | | | | | | | The SORT_NATURAL and SORT_FLAG_CASE were added | | | to $array1_sort_flags as possible sort flags. | | | | | 5.3.0 | | | | | | | The SORT_LOCALE_STRING was added to | | | $array1_sort_flags as possible sort flags. | | | | +--------+---------------------------------------------------+ EXAMPLES
Example #1 Sorting multiple arrays <?php $ar1 = array(10, 100, 100, 0); $ar2 = array(1, 3, 2, 4); array_multisort($ar1, $ar2); var_dump($ar1); var_dump($ar2); ?> In this example, after sorting, the first array will contain 0, 10, 100, 100. The second array will contain 4, 1, 2, 3. The entries in the second array corresponding to the identical entries in the first array (100 and 100) were sorted as well. array(4) { [0]=> int(0) [1]=> int(10) [2]=> int(100) [3]=> int(100) } array(4) { [0]=> int(4) [1]=> int(1) [2]=> int(2) [3]=> int(3) } Example #2 Sorting multi-dimensional array <?php $ar = array( array("10", 11, 100, 100, "a"), array( 1, 2, "2", 3, 1) ); array_multisort($ar[0], SORT_ASC, SORT_STRING, $ar[1], SORT_NUMERIC, SORT_DESC); var_dump($ar); ?> In this example, after sorting, the first array will transform to "10", 100, 100, 11, "a" (it was sorted as strings in ascending order). The second will contain 1, 3, "2", 2, 1 (sorted as numbers, in descending order). array(2) { [0]=> array(5) { [0]=> string(2) "10" [1]=> int(100) [2]=> int(100) [3]=> int(11) [4]=> string(1) "a" } [1]=> array(5) { [0]=> int(1) [1]=> int(3) [2]=> string(1) "2" [3]=> int(2) [4]=> int(1) } } Example #3 Sorting database results For this example, each element in the $data array represents one row in a table. This type of dataset is typical of database records. Example data: volume | edition -------+-------- 67 | 2 86 | 1 85 | 6 98 | 2 86 | 6 67 | 7 The data as an array, called $data. This would usually, for example, be obtained by looping with mysql_fetch_assoc(3). <?php $data[] = array('volume' => 67, 'edition' => 2); $data[] = array('volume' => 86, 'edition' => 1); $data[] = array('volume' => 85, 'edition' => 6); $data[] = array('volume' => 98, 'edition' => 2); $data[] = array('volume' => 86, 'edition' => 6); $data[] = array('volume' => 67, 'edition' => 7); ?> In this example, we will order by $volume descending, $edition ascending. We have an array of rows, but array_multisort(3) requires an array of columns, so we use the below code to obtain the columns, then perform the sorting. <?php // Obtain a list of columns foreach ($data as $key => $row) { $volume[$key] = $row['volume']; $edition[$key] = $row['edition']; } // Sort the data with volume descending, edition ascending // Add $data as the last parameter, to sort by the common key array_multisort($volume, SORT_DESC, $edition, SORT_ASC, $data); ?> The dataset is now sorted, and will look like this: volume | edition -------+-------- 98 | 2 86 | 1 86 | 6 85 | 6 67 | 2 67 | 7 Example #4 Case insensitive sorting Both SORT_STRING and SORT_REGULAR are case sensitive, strings starting with a capital letter will come before strings starting with a lowercase letter. To perform a case insensitive search, force the sorting order to be determined by a lowercase copy of the original array. <?php $array = array('Alpha', 'atomic', 'Beta', 'bank'); $array_lowercase = array_map('strtolower', $array); array_multisort($array_lowercase, SORT_ASC, SORT_STRING, $array); print_r($array); ?> The above example will output: Array ( [0] => Alpha [1] => atomic [2] => bank [3] => Beta ) SEE ALSO
usort(3), The comparison of array sorting functions. PHP Documentation Group ARRAY_MULTISORT(3)