array_multisort-to sort multiple arrays or multidimensional arrays
Description
BOOL Array_multisort (array ar1 [, mixed arg [, mixed ... [, array ...]] )
Array_multisort
(PHP 4, PHP 5)
Returns TRUE if successful, and returns FALSE if it fails.
Array_multisort () can be used to sort multiple arrays at once, or to sort multidimensional arrays based on one dimension or multidimensional.
The association (string) key name remains unchanged, but the numeric key name is indexed.
The input array is treated as a column of a table and sorted in rows--this is similar to the function of the SQL ORDER BY clause. The first array is the primary array to sort. The rows (values) in the array are the same, sorted by the size of the corresponding values in the next input array, and so on.
The parameter structure of this function is somewhat unusual, but very flexible. The first argument must be an array. Each of the next parameters can be an array or a sort flag listed below.
Sort order Flags:
sort_asc– Sorted by ascending order
sort_desc– Sorted in descending order
Sort Type Flags:
sort_regular– items are compared in the usual way
sort_numeric– the project by numerical comparison
sort_string– items by string comparison
You cannot specify two similar sort flags after each array. The sort flags specified after each array are valid only for the array-the default value SORT_ASC and Sort_regular before that.
Example 1. Sort on multiple arrays
<?php
$ar 1 = Array ("10″," a ");
$ar 2 = Array (1, 3, "2″, 1");
Array_multisort ($ar 1, $ar 2);
Var_dump ($ar 1);
Var_dump ($ar 2);
?>
After sorting in this example, the first array will contain "10″," a ", 100,100. The second array will contain 1, 1, "2″,3." The sequence of items in the second array is exactly the same as the corresponding items in the first array (100 and 100).
Array (4) {
[0]=> string (2) "10″
[1]=> string (1) "a"
[2]=> Int (100)
[3]=> Int (100)
}
Array (4) {
[0]=> Int (1)
[1]=> Int (1)
[2]=> string (1) "2″
[3]=> Int (3)
}
Example 2. Sorting multidimensional arrays
<?php
$ar = Array ("10″, M, a"), Array (1, 3, "2″, 1)");
Array_multisort ($ar [0], SORT_ASC, sort_string,
$ar [1], sort_numeric, SORT_DESC);
?>
After sorting in this example, the first array will contain 10,100,100, "a" (sorted as String ascent), and the second array will contain 1, 3, "2″,1" (sorted as numeric drop).
Example 3. Sorting multi-dimensional array
<?php
$ar = Array (
Array ("10″, One,", "a"),
Array (1, 2, "2″, 3, 1")
);
Array_multisort ($ar [0], SORT_ASC, sort_string,
$ar [1], sort_numeric, SORT_DESC);
Var_dump ($ar);
?>
In this case, after sorting, the first array becomes "10″,100,100,11," "A" (which is sorted as a string in ascending order). The second array will contain 1, 3, "2″, 2, 1" (sorted in descending order as numbers).
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 4. To sort the results of a database
In this example, each cell in the data array represents a row in a table. This is a typical collection of data for database records.
The data in the example are as follows:
Volume | Edition
——-+--–
67 | 2
86 | 1
85 | 6
98 | 2
86 | 6
67 | 7
The data is all stored in an array named data. This is usually achieved by looping through the database, such as MYSQL_FETCH_ASSOC ().
<?php
$data [] = Array (' volume ' =>, ' Edition ' => 2);
$data [] = Array (' volume ' =>, ' edition ' => 1);
$data [] = Array (' volume ' =>, ' Edition ' => 6);
$data [] = Array (' volume ' =>, ' Edition ' => 2);
$data [] = Array (' volume ' =>, ' Edition ' => 6);
$data [] = Array (' volume ' =>, ' edition ' => 7);
?>
In this example, the volume is sorted in descending order and the edition in ascending order.
Now you have an array with rows, but Array_multisort () needs an array of columns, so use the following code to get the columns, and then sort.
<?php
Get a list of columns
foreach ($data as $key => $row) {
$volume [$key] = $row [' volume '];
$edition [$key] = $row [' Edition '];
}
Arranges data in descending order according to volume, sorted by edition ascending order
Sort the $data as the last parameter in a common key
Array_multisort ($volume, Sort_desc, $edition, SORT_ASC, $data);
?>
The data collection is now sorted, and the results are as follows:
Volume | Edition
——-+--–
98 | 2
86 | 1
86 | 6
85 | 6
67 | 2
67 | 7
Example 5. Case-insensitive alphabetical Sorting
Both sort_string and Sort_regular are case-sensitive and uppercase letters precede lowercase letters.
To do a case-insensitive sort, sort by the lowercase letter 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 example above will output:
Array
(
[0] => Alpha
[1] => Atomic
[2] => Bank
[3] => Beta
)
"Translator Note" This function is quite useful, to help understand, please look at the following example:
Example 6. Rank ranking
<?php
$grade = Array ("Score" => Array (70, 95, 70.0, 60, "70″"),
"Name" => Array ("Zhang San", "Li Si", "Wang Wu",
"Zhao Liu", "Liu Qi");
Array_multisort ($grade ["Score"], Sort_numeric, Sort_desc,
Sort fractions as numeric values, from high to low
$grade ["Name"], sort_string, SORT_ASC);
Sort names as strings, from small to large
Var_dump ($grade);
?>
The example above will output:
Array (2) {
["Score"]=>
Array (5) {
[0]=>
INT (95)
[1]=>
String (2) "70″
[2]=>
Float (70)
[3]=>
Int (70)
[4]=>
Int (60)
}
[' Name ']=>
Array (5) {
[0]=>
String (5) "Li Si"
[1]=>
String (6) "Liu Qi"
[2]=>
String (7) "Wang Wu"
[3]=>
String (9) "Zhang San"
[4]=>
String (8) "Zhao Liu"
}
}
In this case, the array containing the scores $grade sorted by score (score) from high to low, and those with the same score are sorted by first name (names) from small to large. After the sort Lee 495 is divided into the first place, Zhao 660 is divided into fifth place without objection. John, Harry and Liu Qi are 70 points, and their rankings are arranged alphabetically by their names, Liu in front of Wang and Zhang at the end. For the sake of distinction, three 70 points are represented by integers, floating-point numbers, and strings, which can be clearly seen in the program output as a result of their ordering.
Supplementary information:
One of the most complex sorting methods for multidimensional array sorting in the PHP language. We will use PHP function Array_multisort () in the actual coding to achieve this complex sort. For example, you first sort a nested array with a normal keyword, and then sort by another keyword. This is very similar to sorting multiple fields with an order BY statement that uses SQL.
php function Asort () to use the specific method of value sorting to parse
Functional features of PHP function Arsort ()
Introduction to the characteristics of PHP natural language sorting
The concrete realization Way of PHP natural language reverse
How to use PHP function Usort () to implement custom sort
The Listing J example gives us a detailed description of how PHP functions Array_multisort () works:
1, "name" => "Boney M", "rating" => 3), array ("id" => 2, "name" => "Take that", "rating" => 1), Array ("ID" => 3, "name" => "The Killers", "rating" => 4), array ("ID" => 4, "name" => "Lusain", "rating" => 3),); foreach ($data as $key => $value) {$name [$key] = $value [name]; $rating [$key] = $value [rating];} array_multisort ($rati Ng, $name, $data); Print_r ($data);? > Here, we simulate a row and column array in the $DATA array. Then I use the PHP function Array_multisort () to rearrange the data collection, first by rating, and then, if rating is equal, sorted by name. Its output results are as follows:
Copy Code code as follows:
Array ([0] => Array
(
[ID] => 2
[Name] => Take that
[Rating] => 1
) [1] => Array
(
[ID] => 1
[Name] => Boney M
[Rating] => 3
)
[2] => Array
(
[ID] => 4
[Name] => Lusain
[Rating] => 3
)
[3] => Array
(
[ID] => 3
[Name] => The Killers
[Rating] => 4
)
)
php function Array_multisort () is one of the most useful functions in PHP, and it has a very wide range of applications. In addition, as you can see in the example, it is able to sort multiple unrelated arrays, or you can use one of these elements as the basis for the next order, and you can sort the database result sets.
