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Detailed explanation of how to find and delete array values in php_PHP tutorial

WBOYOriginal: 2016-07-13 16:57:081001browse

Arrays in PHP are divided into array values and array keys. The editor below will summarize the commonly used operation methods of array values in PHP, including: adding values to the array, judging the values in the array, and deleting specific array values. Students in need can refer to it.

php delete specific array value

First of all

代码如下	复制代码
var_dump($context['linktree']);

Get

代码如下

复制代码

array(3) {
[0]=>
array(2) {
["url"]=>
string(52) “http://127.0.0.1/testforum.cityofsteam.com/index.php”
["name"]=>
string(28) “City of Steam Official Forum”
}
[1]=>
array(2) {
["url"]=>
string(55) “http://127.0.0.1/testforum.cityofsteam.com/index.php#c1″
["name"]=>
string(28) “City of Steam Official Forum”
}
[2]=>
array(2) {
["url"]=>
string(62) “http://127.0.0.1/testforum.cityofsteam.com/index.php?board=4.0″
["name"]=>
string(12) “Announcement”
}
}

I'm going to get rid of the middle one.

Use: unset($context['linktree']['1']);

Result:

The code is as follows

Copy code

代码如下	复制代码
array(2) { [0]=> array(2) { ["url"]=> string(52) “http://127.0.0.1/testforum.cityofsteam.com/index.php” ["name"]=> string(28) “City of Steam Official Forum” } [2]=> array(2) { ["url"]=> string(62) “http://127.0.0.1/testforum.cityofsteam.com/index.php?board=4.0″ ["name"]=> string(12) “Announcement” } }

array(2) {

[0]=>

array(2) {

["url"]=>

string(52) “http://127.0.0.1/testforum.cityofsteam.com/index.php”

代码如下	复制代码
Array ( [0] => apple [1] => banana [3] => dog )

["name"]=>

string(28) “City of Steam Official Forum”
}
[2]=>

array(2) {

代码如下

复制代码

function array_remove(&$arr, $offset)

{

array_splice($arr, $offset, 1);

}

$arr = array('apple','banana','cat','dog');

array_remove($arr, 2);

print_r($arr);

["url"]=> string(62) “http://127.0.0.1/testforum.cityofsteam.com/index.php?board=4.0″ ["name"]=> string(12) “Announcement” } }

There is one less [1] Let the 1 in the middle be automatically numbered:

The code is as follows	Copy code
Array ( [0] => apple [1] => banana [3] => dog )

But the biggest disadvantage of this method is that the array index is not rebuilt, that is, the third element of the array is gone. After checking the information, it turns out that PHP provides this function, but it is very indirect. This function is array_splice(). For ease of use, I encapsulated it into a function for everyone to use:

The code is as follows	Copy code
<🎜>function array_remove(&$arr, $offset)<🎜> <🎜>{ <🎜> <🎜> array_splice($arr, $offset, 1);<🎜> <🎜>}<🎜> <🎜>$arr = array('apple','banana','cat','dog'); <🎜> <🎜> array_remove($arr, 2); <🎜> <🎜> print_r($arr);<🎜> <🎜>?>

After testing, we can know that the element at position 2 has been truly deleted and the index has been re-established.

Program execution result:

The code is as follows

Copy code

代码如下	复制代码
Array ( [0] => apple [1] => banana [2] => dog )

Array ( [0] => apple [1] => banana [2] => dog )

php determines the value in the array

There are special functions, don’t use for loops, system functions can achieve fast search:

in_array

(PHP 4, PHP 5)

in_array — Check if a value exists in an array

Description

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

Search for needle in haystack and return TRUE if found, otherwise return FALSE.

If the value of the third parameter strict is TRUE, the in_array() function will also check whether the type of needle is the same as that in haystack.

Note: If needle is a string, the comparison is case-sensitive.

Note: Prior to PHP version 4.2.0, needle was not allowed to be an array.

Example 292. in_array() example

代码如下	复制代码
$os = array("Mac", "NT", "Irix", "Linux"); if (in_array("Irix", $os)) { echo "Got Irix"; } if (in_array("mac", $os)) { echo "Got mac"; } ?>

The code is as follows

Copy code

$os = array("Mac", "NT", "Irix", "Linux");

if (in_array("Irix", $os)) {

echo "Got Irix";

}

if (in_array("mac", $os)) {

echo "Got mac";

代码如下

复制代码

$a = array('1.10', 12.4, 1.13);

if (in_array('12.4', $a, true)) {
echo "'12.4' found with strict checkn";
}
if (in_array(1.13, $a, true)) {
echo "1.13 found with strict checkn";
}
?>
上例将输出：

1.13 found with strict check

}

代码如下

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$a = array(array('p', 'h'), array('p', 'r'), 'o');

if (in_array(array('p', 'h'), $a)) {
echo "'ph' was foundn";
}
if (in_array(array('f', 'i'), $a)) {
echo "'fi' was foundn";
}
if (in_array('o', $a)) {
echo "'o' was foundn";
}
?>
上例将输出：

'ph' was found
'o' was found

The second condition fails because in_array() is case sensitive, so the above program reads: Got Irix Example 293. in_array() strict type checking example

The code is as follows	Copy code
$a = array('1.10', 12.4, 1.13);<🎜> <🎜>if (in_array('12.4', $a, true)) {<🎜> echo "'12.4' found with strict checkn";<🎜> }<🎜> if (in_array(1.13, $a, true)) {<🎜> echo "1.13 found with strict checkn";<🎜> }<🎜> ?> The above example will output: 1.13 found with strict check

Example 294. Use array as needle in in_array()

The code is as follows	Copy code
$a = array(array('p', 'h'), array('p', 'r'), 'o');<🎜> <🎜>if (in_array(array('p', 'h'), $a)) {<🎜> echo "'ph' was foundn";<🎜> }<🎜> if (in_array(array('f', 'i'), $a)) {<🎜> echo "'fi' was foundn";<🎜> }<🎜> if (in_array('o', $a)) {<🎜> echo "'o' was foundn";<🎜> }<🎜> ?> The above example will output: 'ph' was found 'o' was found

Add values to an array

We can implement this through functions, inserting one or more elements into the array, or adding them directly.
(1) Add data directly to the array. The subscript of the new element starts after the maximum subscript of the original array.
(2) The array_unshift() function adds one or more elements to the beginning of the array.
The syntax is as follows:
int array_unshift (array &array, mixed var [,mixed ...]) ;
array_unshift() inserts the passed in element to the beginning of the array array. Elements are inserted as a whole, and incoming elements will remain in the same order. All numeric key names will be counted again from 0, and text key names will remain unchanged.
(3) The array_push() function adds one or more cells to the end of the array.
Syntax:
int array_push (array &array, mixed var [, mixed ...]) ;
array_push() treats the array as a stack and adds the passed variables to the end of the array. This function returns the new total number of cells in the array. An example of adding data to an array is as follows.
Example:

The code is as follows

代码如下

复制代码

$shili = array (“1″,”2″,”3″,”4″) ;
$shili[]=5 ; //直接添加数据
print_r ( $shili ) ;
echo “
” ;
$shili2 = array (“m”,”n”) ;
array_unshift ($shili2,”o”,”p”) ; //添加元素于数组的开头
print_r ( $shili2 ) ;
echo “
” ;
$shili3 = array (“Php”) ;
array_push ($shili3, “MySQL”,”Apache”) ; //添加元素于数组的末尾
print_r ($shili3) ;
?>
结果为：
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 )
Array ( [0] => o [1] => p [2] => m [3] => n )
Array ( [0] => Php [1] => MySQL [2] => Apache )

Copy code

$shili = array (“1″,”2″,”3″,”4″) ; $shili[]=5 ; //Add data directly

print_r ( $shili ) ;

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