Question

是否可以限制此循环..只需要四个循环？

我在另一篇文章中得到了这个来源并且它正在工作，但我只需要限制循环

        $scraper = new DOMScraper();
       $scraper->setSite('http://anywebsite.com/testig12.aspx')->setSource();
        Class DOMScraper extends DOMDocument{
        public $site;
        private $source;
        private $dom;

    function __construct(){
    libxml_use_internal_errors(true);
    $this->preserveWhiteSpace = false;
    $this->strictErrorChecking = false;
}

function setSite($site){
    $this->site = $site;
    return $this;
}

 function setSource(){
     if(empty($this->site))return 'Error: Missing $this->site, 
     use  setSite() first';
     $this->source = $this->get_data($this->site);
     return $this;
 }

 function getInnerHTML($tag, $id=null, $nodeValue = false){
    if(empty($this->site))return 'Error: Missing $this->source, 
    use setSource() first';
    $this->loadHTML($this->source);
    $tmp = $this->getElementsByTagName($tag);
    $ret = null;
    foreach ($tmp as $v){ 
        if($id !== null){
            $attr = explode('=',$id);
            if($v->getAttribute($attr[0])==$attr[1]){
                if($nodeValue == true){
                    $ret .= trim($v->nodeValue);
                }else{
                    $ret .= $this->innerHTML($v);
                }
            }
        }else{
            if($nodeValue == true){
                $ret .= trim($v->nodeValue);
            }else{
                $ret .= $this->innerHTML($v);
            }
        }
    }
    return $ret;
 }

 function innerHTML($dom){
    $ret = "";
    $nodes = $dom->childNodes;
    foreach($nodes as $v){
        $tmp = new DOMDocument();
        $tmp->appendChild($tmp->importNode($v, true));
        $ret .= trim($tmp->saveHTML());
    }
    return $ret;
 }

  function get_data($url){
    if(function_exists('curl_init')){
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
        curl_setopt($ch, CURLOPT_TIMEOUT, 5);
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        $data = curl_exec($ch);
        curl_close($ch);
        return $data;
    }else{
        return file_get_contents($url);
    }
}
  }
  ?>

然后在这里我想限制显示因为它不会废弃该网站的所有数据，如2000条记录..我只想加载最新的4

 <?php echo '<div>'.$scraper->getInnerHTML('div','id=LeftDiv12').'</div>'; ?>

谢谢

Answer 1

只需使用这样的虚拟计数变量：

$Count = 0;
foreach($Array as $Key => $Value){
    //your code

    $Count++;
    if ($Count == 4){
        break; //stop foreach loop after 4th loop
    }
}

Answer 2

可以用来限制foreach循环的一种方法是在foreach循环之外创建一个变量，并在每次循环运行时向变量添加一个变量。然后在一定次数后退出循环。我已经修改了你的功能以完成我上面描述的功能。

from bokeh.plotting import figure, output_file, show,hplot
from bokeh.charts import Bar

data2=[65.75, 48.400000000000006, 58.183333333333337, 14.516666666666666]


bar = Bar(values=data2,xlabel="beef,pork,fowl,fish",ylabel="Avg consumtion", width=400)

show(bar)

Answer 3

不确定您指的是哪个循环，但您可以在循环外创建一个计数器，然后在循环内递增。在计数器上包含一个if语句＆gt; = 4

$counter = 0;
foreach($nodes as $v){
if($counter>=4){
    break;
}   
$tmp = new DOMDocument();
$tmp->appendChild($tmp->importNode($v, true));
$ret .= trim($tmp->saveHTML());
$counter++;}

可能有点笨拙，但它会完成工作。

如何将foreach循环限制为四个循环

3 个答案: