如何从对象中获取唯一属性的列表 - How to get a list of unique properties from object

How to get a list of unique properties from object

我有一个具有'category'属性的对象数组。我需要得到不同类别的列表，如果我有方法从对象中获得类别，我该怎么做呢?下面所示创建了数组中所有类别的列表，但显然有许多重复的类别:

    foreach (getSourceCodes() as $source) {
        echo $source->getCategory();
    }

您可以在php中使用array_unique()

$categories = array();
foreach (getSourceCodes() as $source) {
    array_push($categories, $source->getCategory());
}
$categories = array_unique($categories);

如果categories是多维的，则使用此方法序列化它，然后获得唯一数组，然后将其更改回数组。

$categories = array_map("unserialize", array_unique(array_map("serialize", $categories)));

如果使用类别作为数组键，则根据定义它将是唯一的。

foreach (getSourceCodes() as $source) {
    // The value is irrelevant. You can use a counter if you want to keep track of that.
    $an_array[$source->getCategory()] = true;
    // The key is just overwritten for duplicate values of getCategory()
}
// Then you can use array_keys to get the keys as values.
var_dump(array_keys($an_array));

不确定您的列表是什么格式，但假设逗号分隔值…

$aCategories = array();
$aList = array();
    foreach (getSourceCodes() as $source) {
          // Get categories as comma separated string list???
           $sList = $source->getCategory();
           // Convert string list to array
           $aTmpList = explode(",",$sList);
           //Check temp list against current list for new categories
           $aDiffList = array_diff($aList,$atmpList);
           //Merge new categories into current list
            $aList = array_merge($aDiffList,$aList);
       }
       // Convert array to string list
       $sCategories = implode(",", $aList);