php - foreach 循环只转储一个变量

Question

我有以下代码来查找与 preg_match 匹配的 xml 元素

foreach($xml->Items->Item->AlternateVersions->AlternateVersion->Binding as $BookBinding) { //loop through the xml data to find the correct ASIN for the kindle edition
    foreach ($xml->Items->Item->AlternateVersions->AlternateVersion->ASIN as $Kindlestring)
    {
        var_dump ($BookBinding);
        if (preg_match('/Kindle Edition/i',$BookBinding))
        {
            //do stuff
        }
    }
}

然而它只是 var_dumping Binding 的第一个循环，怎么会呢？

Answer 1

我只是在这里猜测，因为我不知道 XML 的结构，但我的猜测是您在 XML 的错误部分上循环。这是我对你应该做什么的猜测：

foreach($xml->Items as $item) {
    $bookBinding  = $item->Item->AlternateVersions->AlternateVersion->Binding;
    $kindleString = $item->Item->AlternateVersions->AlternateVersion->ASIN;

    if (preg_match('/Kindle Edition/i',$BookBinding)) {
        //do stuff
    }
}

而且看起来可能有多个 AlternateVersions 所以你可能需要像这样做一个嵌套循环：

foreach ($xml->Items as $item) {
    foreach ($item->Item->AlternateVersions as $version) {
        $bookBinding  = $version->AlternateVersion->Binding;
        $kindleString = $version->AlternateVersion->ASIN;

        if (preg_match('/Kindle Edition/i',$BookBinding)) {
            //do stuff
        }
    }
}