php 常用数组操作

php常用的数组操作函数,包括数组的赋值、拆分、合并、计算、添加、删除、查询、判断、排序等

array_combine

功能：用一个数组的值作为新数组的键名，另一个数组的值作为新数组的值

<?php
$a = array("one","two","three");
$b = array("一","二","三");
$c = array_combine($a,$b);
print_r($c);
/**结果
*Array ( [one] => 一 [two] => 二 [three] => 三 )
*/

array_chunk

功能：拆分数组成多个数组

<?php
$input_array = array("a"=>"apple","b"=>"blue","c","d","e");
echo "<pre>";
print_r(array_chunk($input_array, 2));
print_r(array_chunk($input_array, 2,True));
echo "</pre>";
/**结果
Array
(
 [0] => Array
  (
   [0] => apple
   [1] => blue
  )
 [1] => Array
  (
   [0] => c
   [1] => d
  )
 [2] => Array
  (
   [0] => e
  )
)
Array
(
 [0] => Array
  (
   [a] => apple
   [b] => blue
  )
 [1] => Array
  (
   [0] => c
   [1] => d
  )
 [2] => Array
  (
   [2] => e
  )
)
*/

array_count_values

功能：统计数组中值出现的次数

<?php
$input_array = array("a"=>"apple","b"=>"blue","c","d","e");
echo "<pre>";
print_r(array_count_values($input_array));
echo "</pre>";
/**结果
Array
(
 [apple] => 1
 [blue] => 1
 [c] => 1
 [d] => 1
 [e] => 1
)
*/

array_diff

功能：第一个数组中去掉第二个数组中有的数据，返回剩下的内容作为结果

<?php
$array1 = array("a"=>"apple","b"=>"blue","c","d","e");
$array2 = array("apple","c","d","f");
$result = array_diff($array1, $array2);
$result2 = array_diff($array2, $array1);
echo "<pre>";
print_r($result);//数组1中去掉数组2中剩下的
print_r($result2);//数组2中去掉数组1中剩下的
echo "</pre>";
/**结果
Array
(
 [b] => blue
 [2] => e
)
Array
(
 [3] => f
)
*/

array_map

功能：将回调函数执行到数组中

<?php
//定义回调函数
function cube($n){
 return ($n*$n*$n);
}
$a = array(1,2,3,4,5);
$b = array_map("cube",$a);
echo "<pre>";
print_r($b);
echo "</pre>";
/**结果
Array
(
 [0] => 1
 [1] => 8
 [2] => 27
 [3] => 64
 [4] => 125
)
*/

array_merge

功能：合并一个或多个数组

说明：如果后面有键名相同的会覆盖掉前面的内容，键名为数字的会添加到后面

<?php
$array1 = array("color"=>"red",2,4);
$array2 = array("a","b","color"=>"green","shape"=>"trapezoid",4);
$result1 = array_merge($array1,$array2);
$result2 = array_merge_recursive($array1,$array2);
echo "<pre>";
print_r($result1);
print_r($result2);
echo "</pre>";
/**结果
Array
(
 [color] => green
 [0] => 2
 [1] => 4
 [2] => a
 [3] => b
 [shape] => trapezoid
 [4] => 4
)
Array
(
 [color] => Array
  (
   [0] => red
   [1] => green
  )
 [0] => 2
 [1] => 4
 [2] => a
 [3] => b
 [shape] => trapezoid
 [4] => 4
)
*/

array_pop

功能：剔除数组最后一个元素，返回被剔除的元素内容

<?php
$stack = array("orange","banana","apple","1");
$last = array_pop($stack);
echo "<pre>";
print_r($stack);
print_r($last);
echo "</pre>";
/**结果
Array
(
 [0] => orange
 [1] => banana
 [2] => apple
)
1
*/

array_push

功能：将一个多个单元压入数组末尾，返回之后的数组个数

<?php
$stack = array("orange","banana");
$count = array_push($stack,"apple","red","blue");
echo "<pre>";
print_r($stack);
print_r($count);
echo "</pre>";
/**结果
Array
(
 [0] => orange
 [1] => banana
 [2] => apple
 [3] => red
 [4] => blue
)
5
*/

array_rand

功能：获取随机的键名

<?php
$input = array("orange","banana","apple","red","blue");
$rand = array_rand($input,2);;
print_r($rand);
$rand = array_rand($input,3);
print_r($rand);
/**结果
Array
(
 [0] => 1
 [1] => 4
)
Array
(
 [0] => 0
 [1] => 1
 [2] => 3
)
*/

array_search

功能：查询数组中的内容，返回键值，如果有多个匹配，返回第一个匹配的内容

<?php
$array = array("blue"=>"b","red"=>"r","green","r");
$key = array_search('b', $array);
echo $key;
echo "<br>";
$key = array_search('r', $array);
echo $key;
echo "<br>";
/**结果
blue
red
*/

array_shift

功能：移除开头的元素，与array_pop相反

<?php
$fruit = array("milk","orange","banana","apple");
$top = array_shift($fruit);
print_r($top);
echo "<br>";
print_r($fruit);
/**结果
milk
Array ( [0] => orange [1] => banana [2] => apple )
*/

array_unique

功能：去除数组重复的元素，保留第一个出现的，包括键名和值

<?php
$input = array("a"=>"green","red","b"=>"green","blue","c"=>"red");
$result = array_unique($input);
print_r($result);
echo "<br>";
print_r($input);
/**结果
Array ( [a] => green [0] => red [1] => blue )
Array ( [a] => green [0] => red [b] => green [1] => blue [c] => red )
*/

array_slice

功能：从数组中取出部分元素

<?php
$input = array("a","b","c","d","e");
$output = array_slice($input,2);//第二个参数没有时，表示取到最后一个元素
print_r($output);
echo "<br>";
$output = array_slice($input,-2,1);//第二个参数是正数时，表示个数；倒数第一个是-1，倒数第二个是-2
print_r($output);
echo "<br>";
$output = array_slice($input,0,3);
print_r($output);
echo "<br>";
$output = array_slice($input,2,-1);//第二个参数是负数时，表示位置，取到哪一位，不包括本身
print_r($output);
echo "<br>";
$output = array_slice($input,2,-1,true);//第三个参数为true时，保留原有的键值
print_r($output);
echo "<br>";
/**结果
Array ( [0] => c [1] => d [2] => e )
Array ( [0] => d )
Array ( [0] => a [1] => b [2] => c )
Array ( [0] => c [1] => d )
Array ( [2] => c [3] => d )
*/

count

功能：返回数组元素个数，元素为数组的算一个

<?php
$input = array("a","b","c",array("d","e"));
$count = count($input);
echo $count;
echo "<br>";
$input = array("a","b","c","d","e");
$count = count($input);
echo $count;
/**结果
4
5
*/

current

功能:获取当前的指针指向元素

<?php
$array = array("foot","bike","car","plane");
$result = current($array);
echo $result."<br>";
next($array);//使指针指向下一个元素
$result = current($array);
echo $result."<br>";
prev($array);//使指针指向前一个元素
$result = current($array);
echo $result."<br>";
end($array);//使指针指向最后一个元素
$result = current($array);
echo $result."<br>";
/**结果
foot
bike
foot
plane
*/

in_array

功能：检验某值是否存在数组中，有返回True，没有返回False

<?php
$os_list = array("Mac","NT","Irix","Linux");
if(in_array("Irix",$os_list)){
 echo "当前操作系统列表中存在Irix";
}else{

 echo "当前操作系统列表中不存在Irix";
}
echo "<br>";
if(in_array("mac",$os_list)){
 echo "当前操作系统列表中存在mac";
}else{
 echo "当前操作系统列表中不存在mac";
}
echo "<br>";
/**结果
当前操作系统列表中存在Irix
当前操作系统列表中不存在mac
*/

list

功能：将数组中的信息赋值给多个变量

<?php
$info = array("red","blue","green");
list($flag,$sky,$grassland) = $info;
echo "$flag,$sky,$grassland";
echo "<br>";
list($flag,,$grassland) = $info;
echo "$flag,$grassland";
echo "<br>";
list(,,$grassland) = $info;
echo "$grassland";
echo "<br>";
/**结果
red,blue,green
red,green
green
*/

shuffle

功能：打乱数组

<?php
$numbers = range(1,5);//生成一个随机数组
print_r($numbers);
echo "<br/>";
shuffle($numbers);//打乱数组
print_r($numbers);
/**结果
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 )
Array ( [0] => 4 [1] => 1 [2] => 5 [3] => 2 [4] => 3 )
*/

array_keys

功能：获取数组的键名，第二个参数可以指定获取某个元素

<?php
$array = array(0=>100,"color"=>"red");
print_r(array_keys($array));
echo "<br>";
$array = array("blue","red","green","blue","blue");
print_r(array_keys($array,"blue"));
echo "<br>";
$array = array("color"=>array("blue","red","green"),"size"=>array("small","medium","large"));
print_r(array_keys($array));
echo "<br>";
/**结果
Array ( [0] => 0 [1] => color )
Array ( [0] => 0 [1] => 3 [2] => 4 )
Array ( [0] => color [1] => size )
*/

array_reverse

功能：获取数组的反向

<?php
$input = array("php",3.0,array("green","red"));
$result = array_reverse($input); //打乱键名
$result_keyed = array_reverse($input,TRUE);//保留键名
print_r($result);
print_r($result_keyed);
/**结果
Array
(
 [0] => Array
  (
   [0] => green
   [1] => red
  )
 [1] => 3
 [2] => php
)
Array
(
 [2] => Array
  (
   [0] => green
   [1] => red
  )
 [1] => 3
 [0] => php
)
*/

arsort

功能：逆向排序，索引不变

<?php
$fruits = array(
 "a"=>"lemon",
 "b"=>"orange",
 "c"=>"banana",
 "d"=>"apple",
 );
arsort($fruits);//按照字符逆向排序或数字
foreach($fruits as $key=>$val){
 echo "$key = $val<br>";
}
/**结果
b = orange
a = lemon
c = banana
d = apple
*/

asort

功能：进行正向排序

<?php
$fruits = array(
 "a"=>"lemon",
 "b"=>"orange",
 "c"=>"banana",
 "d"=>"apple",
 );
arsort($fruits);//按照字符逆向排序或数字
foreach($fruits as $key=>$val){
 echo "$key = $val<br>";
}
echo "<p>";
asort($fruits);//按照字符正向排序或数字
foreach($fruits as $key=>$val){
 echo "$key = $val<br>";
}
/**结果
b = orange
a = lemon
c = banana
d = apple
d = apple
c = banana
a = lemon
b = orange
*/

krsort

功能：按照键名进行逆向排序

<?php
$fruits = array(
 "a"=>"lemon",
 "b"=>"orange",
 "c"=>"banana",
 "d"=>"apple",
 );
krsort($fruits);//按照键名逆向排序或数字
foreach($fruits as $key=>$val){
 echo "$key = $val<br>";
}
/**结果
d = apple
c = banana
b = orange
a = lemon
*/

ksort

功能：按照键名进行正向排序

<?php
$fruits = array(
 "a"=>"lemon",
 "b"=>"orange",
 "c"=>"banana",
 "d"=>"apple",
 );
ksort($fruits);//按照键名正向排序或数字
foreach($fruits as $key=>$val){
 echo "$key = $val<br>";
}
/**结果
a = lemon
b = orange
c = banana
d = apple
*/

rsort

功能：按照值进行逆向排序，键名改变

<?php
$fruits = array(
 "a"=>"lemon",
 "b"=>"orange",
 "c"=>"banana",
 "d"=>"apple",
 );
rsort($fruits);//按照值进行逆向排序或数字，键名改变
foreach($fruits as $key=>$val){
 echo "$key = $val<br>";
}
/**结果
0 = orange
1 = lemon
2 = banana
3 = apple
*/

sort

功能：按照值进行正向排序，键名改变

<?php
$fruits = array(
 "a"=>"lemon",
 "b"=>"orange",
 "c"=>"banana",
 "d"=>"apple",
 );
sort($fruits);//按照值进行逆向排序或数字，键名改变
foreach($fruits as $key=>$val){
 echo "$key = $val<br>";
}
/**结果
0 = apple
1 = banana
2 = lemon
3 = orange
*/