How to use array_filter in php

array_filter—Use callback function to filter elements in the array

(PHP 4 >= 4.0.6, PHP 5, PHP 7) array_filter — Use a callback function to filter cells in an array

Pass each value in the input array to the callback function in turn. If the callback function returns TRUE, the current value of the input array will be included in the returned result array. The key names of the array remain unchanged.(Recommended learning:PHP video tutorial)

Return value: Return the filtered array

$arr = array( 
"1", 
"2", 
"3", 
"4", 
"5", 
"", 
"6", 
"7", 
"8", 
false, 
"14", 
"15", 
"195", 
"", 
"9", 
); 
//删除空字符串和false 
$re1 = array_filter($arr);
var_dump($re1); 
echo "------------------\n";
function add($num) { 
 $num = intval($num); 
 if($num >6) { 
 return true; 
 } 
 return false; 
} 
$res = array_filter($arr,"add");
var_dump($res);

Running result:

array(12) {
 [0]=>
 string(1) "1"
 [1]=>
 string(1) "2"
 [2]=>
 string(1) "3"
 [3]=>
 string(1) "4"
 [4]=>
 string(1) "5"
 [6]=>
 string(1) "6"
 [7]=>
 string(1) "7"
 [8]=>
 string(1) "8"
 [10]=>
 string(2) "14"
 [11]=>
 string(2) "15"
 [12]=>
 string(3) "195"
 [14]=>
 string(1) "9"
}
------------------
array(6) {
 [7]=>
 string(1) "7"
 [8]=>
 string(1) "8"
 [10]=>
 string(2) "14"
 [11]=>
 string(2) "15"
 [12]=>
 string(3) "195"
 [14]=>
 string(1) "9"

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