Common functions of php array_PHP tutorial-PHP Tutorial-php.cn

In the PHP tutorial, array is a powerful data type. It can do many things. It can store different data types in an array. Below we list the common operations of arrays, sorting, and sorting arrays by key name. etc.

/* Common functions for arrays
*
* Array sorting function
* sort()
* rsort()
* usort()
* asort()
* arsort()
* uasort()
* ksort()
* krsort()
* uksort()
* uatsort()
* natcasesort()
* array_multisort()
*
* 1. Simple array sorting
* sort() rsort()
* 2. Sort the array according to the key name
* ksort() krsort()
* 3. Sort the array according to the value of the element
* asort() arsort()
* 4. Sort the array according to the "natural number sorting" method
* natsort()//Comparison of uppercase and lowercase letters natcasescort()//Comparison of insensitive letters
* 5. Sort the array according to user-defined rules
* usort() uasort() uksort() sorts keys
* 6. Sorting of dimensional arrays
* array_multisort()
*
* Array functions for splitting, merging, decomposing, and joining
* 1.array_slice()
* 2.array_splice()//Delete
* 3.array_combine()//Combine
* 4.array_merge();//Merge
* 5.array_intersect();//Intersection of multiple arrays
* 6.array_diff();//Return the difference set of multiple arrays
*
* Array and data structure functions
* 1. Use arrays to implement stack //First in, last out
* array_push() array_pop()
* 2. Use arrays to implement queues //first in, first out
* array_unshift() array_shift() unset()
*
*
* Other functions related to array operations
* array_rand()
* shuffle()
* array_sum()
* range()
*/

//The use of simple array sorting
$data=array(5,8,1,7,2);
sort($data);//Sort elements from small to large
print_r($data);//Array ( [0] => 1 [1] => 2 [2] => 5 [3] => 7 [4] => 8 )
rsort($data);//Sort elements from large to small
print_r($data);//Array ( [0] => 8 [1] => 7 [2] => 5 [3] => 2 [4] => 1 )

//Example of sorting based on key name
$data_2=array(5=>"five",8=>"eight",1=>"one",7=>"seven",2=>"two");
ksort($data_2);//Sort the subscripts of the array from small to large
print_r($data_2);//Array ( [1] => one [2] => two [5] => five [7] => seven [8] => eight )
krsort($data_2);//Sort the subscripts of the array from large to small
print_r($data_2);//Array ( [8] => eight [7] => seven [5] => five [2] => two [1] => one )

//Sort the array according to the value of the element
$data_3=array("1"=>"Linux","a"=>"Apache","m"=>"MySQL","l"=>"PHP");
//asort() arsort The difference between sort() rsort() is that the former keeps the original key names after sorting, while the latter does not keep the original key names, and the key names start from 0
asort($data_3);
print_r($data_3);//Array ( [a] => Apache [1] => Linux [m] => MySQL [l] => PHP )
echo '
';
arsort($data_3);
print_r($data_3);//Array ( [l] => PHP [m] => MySQL [1] => Linux [a] => Apache )
echo '
';
sort($data_3);
print_r($data_3);//Array ( [0] => Apache [1] => Linux [2] => MySQL [3] => PHP )
echo '
';
rsort($data_3);
print_r($data_3);//Array ( [0] => PHP [1] => MySQL [2] => Linux [3] => Apache )

//Sort the array according to the "natural number sorting method" (the shorter one from 0-9 is given priority)
$data_4=array("file.txt","file11.txt","file2.txt","file22.txt");
sort($data_4);
print_r($data_4);//Array ( [0] => file.txt [1] => file11.txt [2] => file2.txt [3] => file22.txt )
echo '
';
natsort($data_4);
print_r($data_4);//Array ( [0] => file.txt [2] => file2.txt [1] => file11.txt [3] => file22.txt )
echo '
';
natcasesort($data_4);
print_r($data_4);//Array ( [0] => file.txt [2] => file2.txt [1] => file11.txt [3] => file22.txt )
echo '
';

//User-defined sorting function
echo '
';
$data_5=array("Linux","Apache","MySQL","PHP");
usort($data_5,"sortbylen");//Sort by element length
print_r($data_5);//Array ( [0] => PHP [1] => MySQL [2] => Linux [3] => Apache )
function sortbylen($one,$two){
if(strlen($one)==strlen($two))
Return 0;
else
return (strlen($one)>strlen($two))?1:-1;
}

//Array functions for splitting, merging, decomposing, and joining
echo '
';
$data_6=array("Linux","Apache","MySQL","PHP");
print_r(array_slice($data_6,1,2));//Remove the elements marked 1 and 2
//Array ( [0] => Apache [1] => MySQL ) subscript reset starts from 0
echo '
';

print_r(array_slice($data_6,-2,1));//Retrieve one starting from the second one at the end, not starting from 0
//Array ([0] => MySQL) subscript reset starts from 0
echo '
';

print_r(array_slice($data_6,1,2,true));
//Array ( [1] => Apache [2] => MySQL ) retain the original subscript

echo '
';

//array_combine()
$a1=array("OS","WebServer","DataBase","Language");
$a2=array("Linux","Apache","MySQL","PHP");

print_r(array_combine($a1,$a2));//The first parameter is used as the key name, and the second parameter is used as the value to merge
//Array ( [OS] => Linux [WebServer] => Apache [DataBase] => MySQL [Language] => PHP )

echo '
';

//array_merge()
$a3=array("OS","WebServer","DataBase","Language");
$a4=array("Linux","Apache","MySQL","PHP");
$a5=$a3+$a4;
print_r($a5);//Because the two array subscripts are repeated, it is displayed like this
//Array ( [0] => OS [1] => WebServer [2] => DataBase [3] => Language )
echo '
';
print_r(array_merge($a3,$a4));//Merge and re-index
//Array ( [0] => OS [1] => WebServer [2] => DataBase [3] => Language [4] => Linux [5] => Apache [6] = > MySQL [7] => PHP )

echo '
';

//array_intersect()
$a7=array("OS","WebServer","DataBase","Language",1,2,3);
$a8=array("Linux","Apache","MySQL","PHP",2,3,4);
print_r(array_intersect($a7,$a8));//Array ( [5] => 2 [6] => 3 )
echo '
';

//array_diff()
$a9=array(1,2,3,4);
$a10=array(3,4,5,6);
print_r(array_diff($a9,$a10));//Array ( [0] => 1 [1] => 2 )
//Return the difference between the first array and the second element
echo '
';

//Use array to implement stack
$b=array(1,2,3,4);
$b[]="a";//Push into stack
array_push($b,"b","c");//Use function to push onto the stack
print_r($b);//Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => a [5] => ; b [6] => c )
echo '
';

$value=array_pop($b);//Use function to pop
print_r($b);//Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => a [5] => ; b )
echo '
';
echo $value;//Display the value of the element popped off the stack c
echo '
';

//Use array to implement queue
$c=array(1,2,3);
print_r($c);//Array ( [0] => 1 [1] => 2 [2] => 3 )
echo '
';
array_unshift($c,"abc","bcd");//Enqueue
print_r($c);//Array ( [0] => abc [1] => bcd [2] => 1 [3] => 2 [4] => 3 )
echo '
';
$values=array_shift($c);//Dequeue
print_r($c);// Array ( [0] => bcd [1] => 1 [2] => 2 [3] => 3 )
echo '
';
unset($c[2]);//Delete the element at the specified position
print_r($c);//Array ( [0] => bcd [1] => 1 [3] => 3 )
echo '
';

//array_rand() Randomly returns array subscript
$arr=array(1,3,4,5,76,7,99,6,2,3);
echo array_rand($arr);//Returns the subscript of a random array element
echo $arr[array_rand($arr)];//Randomly display the value of the array element
echo '
';
//shuffle() randomly rearranges the array
$arr2=array(32,35,33);
shuffle($arr2);
print_r($arr2);//Array element position is randomly transformed
echo '
';
//array_sum() Sum
$arr3=array(1,3,5);
echo array_sum($arr3); //Return 9
echo '
';
print_r($arr3);//Array ( [0] => 1 [1] => 3 [2] => 5 )
echo '
';
//range(minimum value, maximum value, step size)
$arr4=range(0,100,10);
print_r($arr4);//Array ( [0] => 0 [1] => 10 [2] => 20 [3] => 30 [4] => 40 [5] => ; 50 [6] => 60 [7] => 70 [8] => 80 [9] => 90 [10] => 100 )

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