添加到数组(如果还不存在) [英] add to array if it isn't there already

问题描述

仅当元素不在数组中时才如何将其添加到数组中?我有以下内容:

How do I add elements to an array only if they aren't in there already? I have the following:

$a=array();
// organize the array
foreach($array as $k=>$v){
    foreach($v as $key=>$value){
        if($key=='key'){
        $a[]=$value;
        }
    }
}

print_r($a);

//输出

Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 1
[4] => 2
[5] => 3
[6] => 4
[7] => 5
[8] => 6

)

相反，我希望$ a包含唯一值. (我知道我可以使用array_unique获得所需的结果，但我只是想知道)

Instead, I want $a to consist of the unique values. (I know I can use array_unique to get the desired results but I just want to know)

推荐答案

您必须对照 in_array检查每个值:

$a=array();
// organize the array by cusip
foreach($array as $k=>$v){
    foreach($v as $key=>$value){
        if(!in_array($value, $a)){
        $a[]=$value;
        }
    }
}

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