Question

我试图从一个充满新闻项及其参数的数组中获取特定值。

我的阵列有25个项目，来自6个不同的类别，我只需要获取类别名称但不能获得25次。如果我不完全清楚，那就说出来

这是print_r($this->primary)：

Array(
    [0] => stdClass Object
        (
         [title]=> Title 1
         [categoryname]=> Cat1
         [categoryid]=> 2
        )
   [1] => stdClass Object
        (
         [title]=> Title 2
         [categoryname]=> Cat1
         [categoryid]=> 2
        )


   [2] => stdClass Object
        (
         [title]=> Title 3
         [categoryname]=> Cat2
         [categoryid]=> 3
        )
   [3] => stdClass Object
        (
         [title]=> Title 4
         [categoryname]=> Cat2
         [categoryid]=> 3
        )
)

我的循环是：

for each ($getids->categories as $key=>$mycategory)
{
    echo ' <h2> CAT NAME SHOULD GO HERE</h2> ';
    for each ($this->primary as $key=>$item){
        if ($mycategory == $item->categoryid){
            echo $item->title;
        }
    }
}

问题是我需要在开始for each之前使用类别名称。愚蠢的是$getids->categories除了类别ID之外没有给我任何其他东西。我无法使用$this->primary[0]获取它，因为这些项目不是按类别分组，而是如上所示只是滚动到数组中，

任何帮助表示赞赏。谢谢！

编辑：这是print_r($getids->categories)：

Array ( [0] => 11 [1] => 14 [2] => 12 [3] => 13 [4] => 15 [5] => 21 [6] => 20 [7] => 29 )

Answer 1

使用当前设置，除了将categoryName调用25次外，您别无选择。如果你想避免这样做，我会考虑重构你的代码，以便$ this-＆gt; primary不会充满所有内容。假设您从模型中获取这些值，您可以将模型函数更改为按类别名称限制。

foreach($categoryNames as $categoryName) {
    $this->primaryArray[$categoryName] = Foo.getByCategoryName($categoryName);
}

foreach($this->primaryArray as $categoryName => $primary) {
    echo '<h2>' . $categoryName . '</h2>';
    foreach($primary as $key=>$item){
        echo $item->title;
    }
}

修改

按类别排序（尽管您仍会拨打25次）：

$primaryArray = array();

// sort array by category
foreach($this->primary as $value) {
    $primaryArray[$value->categoryName] = $value;
}

foreach($primaryArray as $categoryName => $primary) {
    echo '<h2>' . $categoryName . '</h2>';
    foreach($primary as $key=>$item){
        echo $item->title;
    }
}

Answer 2

假设您想要保留$ getids-＆gt;类别返回的类别顺序，您可以尝试这样的事情：

//Group items by category.
$itemsByCategory = array()
foreach($this->primary as $item) {
    if ( !isset($itemsByCategory[$item->categoryid] ) {
        $itemsByCategory[$item->categoryid] = array();
    }
    $itemsByCategory[$item->categoryid][] = $item;
}

//Print items in each category.
foreach($getids->categories as $mycategory):
    if ( isset($itemsByCategory[$mycategory]) ) {
        $categoryName = $itemsByCategory[$mycategory][0]->categoryname;
        echo '<h2>', $categoryName ,'</h2>';
        foreach($$temsByCategory[$mycategory] as $key=>$item){
           echo $item->title;
        }
    }

endforeach;

Answer 3

看看这是否适合您，

foreach($this->primary as $key=>$item)
{
    $headingPrinted = false;
    foreach($getids->categories as $key=>$catID) {
        if($catID == $item->categoryid){
            if (!$headingPrinted) {
                echo '<h2>'.$item->categoryname.'</h2>';
                $headingPrinted = true;
            }
            echo $item->title;
        }
    }
}

从数组中提取值

3 个答案: