mysql 数组处理函数_数组相关处理函数

一、数组键值相关处理函数1. array_values()　　//返回输入的所有值，并建立索引1 $temp=array("os"=>"linux","webserver"=>"Apache", "db"=>"MySql", "laguage"=>"php");2 $arr=array_values($temp);3 echo '';4 print_r($arr);5 ec

李淳风的谜底

1891人浏览 · 2021-01-29 21:45:32

李淳风的谜底 · 2021-01-29 21:45:32 发布

一、数组键值相关处理函数

1. array_values()　　//返回输入的所有值，并建立索引

1 $temp=array("os"=>"linux","webserver"=>"Apache", "db"=>"MySql", "laguage"=>"php");2 $arr=array_values($temp);3 echo '

';4 print_r($arr);5 echo '

';6

7 //result

8 Array

9 (10 [0] =>linux11 [1] =>Apache12 [2] => MySql

13 [3] =>php14 )

2. array_keys()　　//返回数组中所有的键名

array_keys(inputarray,[mixed value])　　//若指定要搜索的值，则返回该值的键名，否则返回全部

1 $temp=array("os"=>"linux","webserver"=>"Apache", "db"=>"MySql", "laguage"=>"php");2 $arr=array_keys($temp);3 echo '

';4 print_r($arr);5 echo '

';6

7 $arr=array_keys($temp, "MySql");8 echo '

';9 print_r($arr);10 echo '

';11

12 //value

13 Array

14 (15 [0] =>os16 [1] =>webserver17 [2] =>db18 [3] =>laguage19 )20 Array

21 (22 [0] =>db23 )

3. bool in_array ( mixed needle, array haystack [, bool strict])

//检查数组中是否存在某个值

1 $temp=array("os"=>"linux","webserver"=>"Apache", "db"=>"MySql", "laguage"=>"php");2 if( in_array("Apache", $temp) ){3 echo 'find Apache!'.'
';4 }5

6 //result

7 find Apache!

4. bool array_key_exists ( mixed key, array search)

//检查给定的键名或者索引是否存在于数组中

$temp=array("os"=>"linux","webserver"=>"Apache", "db"=>"MySql", "language"=>"php");if( array_key_exists("language", $temp) ){echo 'language is in array!'.'
';

}//result

language is inarray!

5. array array_flip ( array trans)

//交换数组中的键和值

1 $temp=array("os"=>"linux","webserver"=>"Apache", "db"=>"MySql", "language"=>"php");2

3 echo '
';4 print_r($temp);5 echo '
';6

7 $temp=array_flip($temp);8 echo '
';9 print_r($temp);10 echo '
';11

12 //result

13 Array ( [os] => linux [webserver] => Apache [db] => MySql [language] =>php )14

15 Array ( [linux] => os [Apache] => webserver [MySql] => db [php] => language )

6. array array_reverse ( array array [, bool preserve_keys])

//返回一个单元顺序相反的数组

1 $temp=array("os"=>"linux","webserver"=>"Apache", "db"=>"MySql", "language"=>"php");2

3 $temp=array_reverse($temp);4 echo '

';5 print_r($temp);6 echo '

';7

8 $temp=array_reverse($temp);9 echo '

';10 print_r($temp);11 echo '

';12

13 //result

14 Array

15 (16 [language] =>php17 [db] => MySql

18 [webserver] =>Apache19 [os] =>linux20 )21 Array

22 (23 [os] =>linux24 [webserver] =>Apache25 [db] => MySql

26 [language] =>php27 )

二、统计数组元素的个数

1. array array_count_values ( array input)

//统计数组中所有值出现的次数,返回的依然是数组

1 $temp=array("os"=>"linux","webserver"=>"Apache", "db"=>"MySql", "language"=>"php");2

3 $count=array_count_values($temp);4

5 print_r($count);6

8 //result

10 Array ( [linux] => 1 [Apache] => 1 [MySql] => 1 [php] => 1 )

2. array array_unique ( array array)

//移除数组中重复的值

1 $temp=array("abc"=>"MySql", "os"=>"linux","webserver"=>"Apache", "db"=>"MySql", "language"=>"php");2

3 $count=array_unique($temp);4

5 print_r($count);6

7 //result

9 Array ( [abc] => MySql [os] => linux [webserver] => Apache [language] => php )

三、使用回调函数处理数组的函数

1. array array_filter ( array input [, callback function])

//回调函数过滤数组中的元素

array_filter() 依次将 input 数组中的每个值传递到 callback 函数。如果 callback 函数返回 TRUE，则 input 数组的当前值会被包含在返回的结果数组中。数组的键名保留不变。

1 function ji($var){2 return ($var % 2 == 1);3 }4 function ou($var){5 return ($var % 2 == 0);6 }7

8 $array1 = array("a"=>1, "b"=>2, "c"=>3, "d"=>4, "e"=>5);9 $array2 = array(6, 7, 8, 9, 10, 11, 12);10

11 echo "jishu: ";12 print_r(array_filter($array1, "ji"));13 echo "oushu: ";14 print_r(array_filter($array2, "ou"));15

16 //result

17 jishu: Array ( [a] => 1 [c] => 3 [e] => 5 ) oushu: Array ( [0] => 6 [2] => 8 [4] => 10 [6] => 12 )

2. bool array_walk ( array array, callback function [, mixed userdata])

//对数组中的每个成员应用用户函数,其中回调函数的第一个值为值，第二个为键，第三个为array_walk的第三个参数

1 function guoyuan($value,$key){2 echo $key.'--is--'.$value.'
';3 }4 function guoyuan1($value,$key,$class){5 echo $class.':'.$key."-is-".$value.'
';6 }7

8 $fruits=array("a"=>"apple", "b"=>"banana", "p"=>"pear", "o"=>"orange");9

10 array_walk($fruits, "guoyuan");11 array_walk($fruits, "guoyuan1","fruits");12

13 //result

14 a--is--apple15 b--is--banana16 p--is--pear17 o--is--orange18 fruits:a-is-apple19 fruits:b-is-banana20 fruits:p-is-pear21 fruits:o-is-orange

3. array array_map ( mixed callback, array arr1 [, array ...])

//将回调函数作用到给定数组的单元上，返回的也是一个数组

function cube($value){return $value*$value*$value;

}$num=array(1,2,3,4,5,6,7,8,9);$cube_num=array_map("cube",$num);echo '

';print_r($cube_num);echo '

';//result

Array(

[0] => 1[1] => 8[2] => 27[3] => 64[4] => 125[5] => 216[6] => 343[7] => 512[8] => 729)

可以传入多个数组，回调函数中参数的个数应该跟传入数组的个数一致

function test($first_n, $sec_n){return $first_n.'--is--'.$sec_n;

}$num=array(1,2,3,4,5,6,7,8,9);$num_en=array("one", "two", "three", "four", "five", "six", "seven", "eight", "nine");$result=array_map("test", $num, $num_en);echo '

';print_r($result);echo '

';//result

Array(

[0] => 1--is--one

[1] => 2--is--two

[2] => 3--is--three

[3] => 4--is--four

[4] => 5--is--five

[5] => 6--is--six

[6] => 7--is--seven

[7] => 8--is--eight

[8] => 9--is--nine

)

可以通过NULL构造一个数组的数组不用回调函数

$num=array(1,2,3,4,5,6,7,8,9);$num_en=array("one", "two", "three", "four", "five", "six", "seven", "eight", "nine");$num_2=array(11,22,33,44,55,66,77,88,99);$result=array_map(NULL, $num, $num_en, $num_2);echo '