How to use PHP array sorting function_PHP tutorial-PHP Tutorial-php.cn

There are many data sorting functions in PHP, including one-dimensional array sorting functions and two-dimensional array sorting functions, including simple sort function ascending sorting, rsort descending order, etc.

PHP array sorting functions include

sort ( &$arr [,fruits] ) Sort the array from low to high and assign a new key name. Return bool
rsort ( &$arr [,fruits] ) Reverse sort the array and assign new key names
asort ( &$arr [,fruits] ) sorts the array, keeping the index unchanged
arsort( &$arr [,fruits] ) sorts the array in reverse order and keeps the index unchanged

ksort ( &$arr [,fruits] ) sorts the array by key name
krsort( &$arr [,fruits] ) sorts the group numbers in reverse order by key name

natsort( &$arr ) Performs ‘natural sorting’ on array key values, sorting by length, alphabet, etc.
natcasesort( &$arr ) performs case-insensitive ‘natural ranking’ of arrays

usort ( &$arr , cmp_function ) User-defined function sorts an array and rearranges key names
uksort (&$arr, cmp_function) User-defined function sorts an array by key name
uasort (&$arr, cmp_function) user-defined function sorts the array and keeps the index unchanged

array_multisort( $arr , mixed)

The second parameter can change the sorting behavior based on the value

SORT_REGULAR Normal comparison unit SORT_NUMERIC unit is compared as a number
SORT_STRING cells are compared as strings SROT_LOCALE_STRING cells are compared as strings according to the current local settings

--------------------sort function ascending order----------------------------- ------
bool sort ( array &$array [, int $sort_flags= SORT_REGULAR ] )

The code is as follows

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代码如下

复制代码

$fruits = array("lemon", "orange", "banana", "apple");
sort($fruits);
var_dump($fruits);
?>
结果：
array

0 =>

string

'apple' (length=5)
1 =>

string

'banana' (length=6)
2 =>

string

'lemon' (length=5)
3 =>

string

'orange' (length=6)

$fruits = array("lemon", "orange", "banana", "apple");

sort($fruits);

代码如下

复制代码

$fruits = array("lemon", "orange", "banana", "apple");
rsort($fruits);
var_dump($fruits);
?>
结果：
array
0 =>

string

'orange' (length=6)
1 =>

string

'lemon' (length=5)
2 =>

string

'banana' (length=6)
3 =>

string

'apple' (length=5)

var_dump($fruits); ?> Result: array 0 => string 'apple' (length=5) 1 => string 'banana' (length=6) 2 => string 'lemon' (length=5) 3 => string 'orange' (length=6) --------------------rsort in descending order--------------------

The code is as follows	Copy code
$fruits = array("lemon", "orange", "banana", "apple");<🎜> rsort($fruits);<🎜> var_dump($fruits);<🎜> ?> Result: array 0 => string 'orange' (length=6) 1 => string 'lemon' (length=5) 2 => string 'banana' (length=6) 3 => string 'apple' (length=5)

---------------asort is arranged in ascending order of the two-dimensional array values (maintaining the association of key=>value)----------

The code is as follows

Copy code

代码如下

复制代码

$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
asort($fruits);
var_dump($fruits);
?>
结果：
array
'c' =>

string

'apple' (length=5)
'b' =>

string

'banana' (length=6)
'd' =>

string

'lemon' (length=5)
'a' =>

string

'orange' (length=6)

$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
asort($fruits);
var_dump($fruits);
?>
Result:
array
'c' =>

string

代码如下

复制代码

$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");
arsort($fruits);
var_dump($fruits);
?>
结果
array
'a' =>

string

'orange' (length=6)
'd' =>

string

'lemon' (length=5)
'b' =>

string

'banana' (length=6)
'c' =>

string

'apple' (length=5)

'apple' (length=5)
'b' =>

代码如下

复制代码

$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
ksort($fruits);
var_dump($fruits);
?>
结果
array

'a' =>

string

'orange' (length=6)
'b' =>

string

'banana' (length=6)
'c' =>

string

'apple' (length=5)
'd' =>

string

'lemon' (length=5)

string

'banana' (length=6)
'd' =>

代码如下

复制代码

$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
krsort($fruits);
var_dump($fruits);
?>

array
'd' =>

string

'lemon' (length=5)
'c' =>

string

'apple' (length=5)
'b' =>

string

'banana' (length=6)
'a' =>

string

'orange' (length=6)

string 'lemon' (length=5)
'a' => string 'orange' (length=6)

--------------arsort is arranged in descending order of the two-dimensional array values (maintaining the association of key=>value)------------- -

The code is as follows	Copy code
$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple"); arsort($fruits); var_dump($fruits); ?> Results array 'a' => string 'orange' (length=6) 'd' => string 'lemon' (length=5) 'b' => string 'banana' (length=6) 'c' => string 'apple' (length=5)

--------------------ksort sorts the array in ascending order of keys----------------

The code is as follows	Copy code
<🎜>$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple"); ksort($fruits); var_dump($fruits); ?> Results array 'a' => string 'orange' (length=6) 'b' => string 'banana' (length=6) 'c' => string 'apple' (length=5) 'd' => string 'lemon' (length=5)

---------------------krsort sorts the array keys in descending order------------------ -------------

The code is as follows	Copy code
$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple"); krsort($fruits); var_dump($fruits); ?> array 'd' => string 'lemon' (length=5) 'c' => string 'apple' (length=5) 'b' => string 'banana' (length=6) 'a' => string 'orange' (length=6)

----------------usort function sorts according to user-defined functions----------------

The code is as follows

Copy code

代码如下

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function cmp($a, $b)
{
if ($a == $b) {
return 0;
}
return ($a < $b) ? -1 : 1;
}

$a = array(3, 2, 5, 6, 1);

usort($a, "cmp");

var_dump($a);
?>
结果：
array
0 =>

int

1
1 =>

int

2
2 =>

int

3
3 =>

int

5
4 =>

int

function cmp($a, $b)
{
If ($a == $b) {
return 0;
}
Return ($a < $b) ? -1 : 1;
}

$a = array(3, 2, 5, 6, 1);

代码如下

复制代码

function cmp($a, $b)
{
$a = preg_replace('@^(a|an|the) @', '', $a);
$b = preg_replace('@^(a|an|the) @', '', $b);
return strcasecmp($a, $b);
}

$a = array("John" => 1, "the Earth" => 2, "an apple" => 3, "a banana" => 4);

uksort($a, "cmp");

var_dump($a);
?>
结果：
array
'an apple' =>

int

3
'a banana' =>

int

4
'the Earth' =>

int

2
'John' =>

int

usort($a, "cmp");

代码如下

复制代码

// Comparison function
function cmp($a, $b) {
if ($a == $b) {
return 0;
}
return ($a < $b) ? -1 : 1;
}

// Array to be sorted
$array = array('a' => 4, 'b' => 8, 'c' => -1, 'd' => -9, 'e' => 2, 'f' => 5, 'g' => 3, 'h' => -4);
var_dump($array);

// Sort and print the resulting array
uasort($array, 'cmp');
var_dump($array);
?>
结果：
array
'a' =>

int

4
'b' =>

int

8
'c' =>

int

-1
'd' =>

int

-9
'e' =>

int

2
'f' =>

int

5
'g' =>

int

3
'h' =>

int

-4
array
'd' =>

int

-9
'h' =>

int

-4
'c' =>

int

-1
'e' =>

int

2
'g' =>

int

3
'a' =>

int

4
'f' =>

int

5
'b' =>

int

var_dump($a);
?>
Result:
array
0 => int 1
1 => int 2
2 => int 3
3 => int 5
4 => int 6 -----------------uksort uses a custom function to sort the array by key-----------------

The code is as follows	Copy code
function cmp($a, $b) { $a = preg_replace('@^(a\|an\|the) @', '', $a); $b = preg_replace('@^(a\|an\|the) @', '', $b); Return strcasecmp($a, $b); }<🎜> <🎜>$a = array("John" => 1, "the Earth" => 2, "an apple" => 3, "a banana" => 4); uksort($a, "cmp"); var_dump($a); ?> Result: array 'an apple' => int 3 'a banana' => int 4 'the Earth' => int 2 'John' => int 1

------------------uasort uses a custom function to sort the array by value, keeping the index relationship unchanged---------

The code is as follows

Copy code

// Comparison function
function cmp($a, $b) {
If ($a == $b) {
return 0;
}
Return ($a < $b) ? -1 : 1;
}<🎜> <🎜>// Array to be sorted
$array = array('a' => 4, 'b' => 8, 'c' => -1, 'd' => -9, 'e' => 2, 'f' => 5, 'g' => 3, 'h' => -4);
var_dump($array); // Sort and print the resulting array
uasort($array, 'cmp');
var_dump($array);
?>
Result:
array
'a' => int 4
'b' => int 8
'c' => int -1
'd' => int -9
'e' => int 2
'f' => int 5
'g' => int 3
'h' => int -4
array
'd' => int -9
'h' => int -4
'c' => int -1
'e' => int 2
'g' => int 3
'a' => int 4
'f' => int 5
'b' => int 8

------------------array_multisort Sort multiple arrays or multidimensional arrays---------

0 =>

The code is as follows

代码如下

复制代码

$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);
?>
结果：
array
0 =>
array
0 =>

string

'10' (length=2)
1 =>

int

100
2 =>

int

100
3 =>

int

11
4 =>

string

'a' (length=1)
1 =>
array
0 =>

int

1
1 =>

int

3
2 =>

string

'2' (length=1)
3 =>

int

2
4 =>

int

Copy code

$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);

?> Result:

array

0 =>

代码如下	复制代码
function array_sort($arr,$keys,$type='asc'){ $keysvalue = $new_array = array(); foreach ($arr as $k=>$v){ $keysvalue[$k] = $v[$keys]; } if($type == 'asc'){ asort($keysvalue); }else{ arsort($keysvalue); } reset($keysvalue); foreach ($keysvalue as $k=>$v){ $new_array[$k] = $arr[$k]; } return $new_array; }

array

string

'10' (length=2)

11 4 =>

string 'a' (length=1) 1 => array 0 => int 1 1 => int 3 2 => string '2' (length=1) 3 => int 2 4 => int 1 //Description: 1 In the above example: the $ar array is first arranged in ascending order according to the string value of $ar[0]. If the string values are equal, it is then arranged in descending order according to the numeric value of the $ar[1] array. 2. If the parameter at any position of the array_multisort function is an array, it indicates the value used for sorting, If there are multiple array parameters, the previous array value will be sorted first. If it is a constant, such as SORT_ASC, SORT_DESC, SORT_REGULAR,SORT_NUMERIC, SORT_STRING. PHP two-dimensional array sorting function You can use sort(), asort(), arsort() and other functions to sort PHP one-dimensional arrays, but the sorting of PHP two-dimensional arrays needs to be customized. The following function sorts a given two-dimensional array according to the specified key value. Let’s look at the function definition first:

The code is as follows

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