php 数组的常用函数

在php教程中数组是种强大的数据类型，他可以做的事情很多，可以存储不同的数据类型在一个数组中，下面我们列出了数组常用的操作，排序，键名对数组排序等做法。

/* 数组的常用函数

 *

 * 数组的排序函数

 *   sort()

 *   rsort()

 *   usort()

 *   asort()

 *   arsort()

 *   uasort()

 *   ksort()

 *   krsort()

 *   uksort()

 *   uatsort()

 *   natcasesort()

 *   array_multisort()

 *

 *    1.简单的数组排序

 *      sort() rsort()

 *    2.根据键名对数组排序

 *      ksort() krsort()

 *    3.根据元素的值对数组排序

 *      asort() arsort()

 *    4.根据"自然数排序“法对数组排序

 *      natsort()//区分大小写字母比较 natcasescort()//不区分大小写字母的比较

 *    5.根据用户自定义规则对数组排序

 *      usort() uasort() uksort()对键排序

 *    6.对维数组的排序

 *      array_multisort()

 *

 * 拆分、合并、分解、接合的数组函数

 *    1.array_slice()

 *    2.array_splice()//删除

 *    3.array_combine()//合并

 *    4.array_merge();//合并

 *    5.array_intersect();//多个数组的交集

 *    6.array_diff();//返回多个数组的差集

 *

 * 数组与数据结构的函数

 *   1.使用数组实现堆栈 //先进后出

 *    array_push() array_pop()

 *   2.使用数组实现队列 //先进先出

 *    array_unshift() array_shift() unset()

 *

 * 

 * 其他与数组操作有关的函数

 *    array_rand()

 *    shuffle()

 *    array_sum()

 *    range()

 */

//简单数组排序的使用

$data=array(5,8,1,7,2);

sort($data);//元素由小到大进行排序

print_r($data);//Array ( [0] => 1 [1] => 2 [2] => 5 [3] => 7 [4] => 8 )

rsort($data);//元素由大到小进行排序

print_r($data);//Array ( [0] => 8 [1] => 7 [2] => 5 [3] => 2 [4] => 1 )

//根据键名排序的例子

$data_2=array(5=>"five",8=>"eight",1=>"one",7=>"seven",2=>"two");

ksort($data_2);//对数组的下标进行由小到大排序

print_r($data_2);//Array ( [1] => one [2] => two [5] => five [7] => seven [8] => eight )

krsort($data_2);//对数组的下标进行由大到小排序

print_r($data_2);//Array ( [8] => eight [7] => seven [5] => five [2] => two [1] => one )

//根据元素的值对数组排序

$data_3=array("1"=>"Linux","a"=>"Apache","m"=>"MySQL","l"=>"PHP");

//asort() arsort  与 sort() rsort()的区别在于 前者排序后保持原有的键名,后者不保持原有键名，且键名从0开始

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 )

//根据”自然数排序法“对数组排序(0-9短者优先)

$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 '

';

//用户自定义排序函数

echo '

';

$data_5=array("Linux","Apache","MySQL","PHP");

usort($data_5,"sortbylen");//通过元素长度排序

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;

}

//拆分、合并、分解、接合的数组函数

echo '

';

$data_6=array("Linux","Apache","MySQL","PHP");

print_r(array_slice($data_6,1,2));//取下标为1、2的元素

//Array ( [0] => Apache [1] => MySQL ) 下标重置从0开始

echo '

';

print_r(array_slice($data_6,-2,1));//从后边的第二个开始取返回一个，不是从0开始的

//Array ( [0] => MySQL ) 下标重置从0开始

echo '

';

print_r(array_slice($data_6,1,2,true));

//Array ( [1] => Apache [2] => MySQL )  保留原有的下标

echo '

';

//array_combine()

$a1=array("OS","WebServer","DataBase","Language");

$a2=array("Linux","Apache","MySQL","PHP");

print_r(array_combine($a1,$a2));//第一个参数作为键名，第二个作为值来合并

//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);//因为两个数组下标重复所以显示这样

//Array ( [0] => OS [1] => WebServer [2] => DataBase [3] => Language )

echo '

';

print_r(array_merge($a3,$a4));//合并并重新索引

//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 )

//返回第一个数组跟第二个相差的元素

echo '

';

//使用数组实现堆栈

$b=array(1,2,3,4);

$b[]="a";//入栈

array_push($b,"b","c");//使用函数入栈

print_r($b);//Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => a [5] => b [6] => c )

echo '

';

$value=array_pop($b);//使用函数出栈

print_r($b);//Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => a [5] => b )

echo '

';

echo $value;//显示出栈的元素的值 c

echo '

';

//使用数组实现队列

$c=array(1,2,3);

print_r($c);//Array ( [0] => 1 [1] => 2 [2] => 3 )

echo '

';

array_unshift($c,"abc","bcd");//入队

print_r($c);//Array ( [0] => abc [1] => bcd [2] => 1 [3] => 2 [4] => 3 )

echo '

';

$values=array_shift($c);//出队

print_r($c);// Array ( [0] => bcd [1] => 1 [2] => 2 [3] => 3 )

echo '

';

unset($c[2]);//删除指定位置元素

print_r($c);//Array ( [0] => bcd [1] => 1 [3] => 3 )

echo '

';

//array_rand()  随机返回数组下标

$arr=array(1,3,4,5,76,7,99,6,2,3);

echo array_rand($arr);//返回的是随机的数组元素的下标

echo $arr[array_rand($arr)];//随机显示数组元素的值

echo '

';

//shuffle()  随机重新排列数组

$arr2=array(32,35,33);

shuffle($arr2);

print_r($arr2);//数组元素位置随机变换

echo '

';

//array_sum()  求和

$arr3=array(1,3,5);

echo array_sum($arr3); //返回9

echo '

';

print_r($arr3);//Array ( [0] => 1 [1] => 3 [2] => 5 )

echo '

';

//range(最小值，最大值，步长)

$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 )

?>