過濾使用二進制

Question

甲PHP數組有一個PHP陣列

$arr = array(
    1 => "a", 
    2 => "b", 
    4 => "c", 
    8 => "d", 
    16 => "e", 
    32 => "f" 
); 

和一個二進制數

$filter=101101 

我要篩選的陣列，只保留鍵，其中二進制的相應值是1 在這個例子中我會：

$arr = array(
    1 => "a", 
    4 => "c", 
    8 => "d", 
    32 => "f" 
); 

或爲

$filter=110001 

得到

$arr = array(
    1 => "a", 
    2 => "b", 
    32 => "f" 
); 

Answer 1

假設的$filter長度總是相同的數組元素的數目：使用您的給定陣列

$filter_arr = str_split($filter); 
$new_arr = array(); 
$i = 0; 
foreach ($arr as $key => $val) { 
    if ($filter_arr[$i] == 1) { 
     $new_arr[$key] = $val; 
    } 
    $i++; 
} 

，並過濾等於101101 ，$new_arr將等於：

Array 
(
    [1] => a 
    [4] => c 
    [8] => d 
    [32] => f 
) 

See demo

Answer 2

這應該爲你工作：

<?php 

    $arr = array(
     1 => "a", 
     2 => "b", 
     4 => "c", 
     8 => "d", 
     16 => "e", 
     32 => "f" 
    ); 

    $filter=110001; 
    $filerValue = str_split($filter); 
    $count = 0; 

    foreach($arr as $k => $v) { 
     if($filerValue[$count] == 0) 
      unset($arr[$k]); 
     $count++; 
    } 

    var_dump($arr); 

?> 

輸出：

array(3) { 
     [1]=> 
     string(1) "a" 
     [2]=> 
     string(1) "b" 
     [32]=> 
     string(1) "f" 
    }