如果输出为空，请执行其他操作？

Question

此代码从道路输出信息。但有时没有信息，然后我想从另一个地方收集信息。我怎样才能做到这一点？

$title = '1234';

foreach(Feed('$url') as $f ) {

  if (strpos($f->title, $title) !== false){

    $pos = $f->children('georss', true)->children('gml', true)->children('gml', true);

    list($number1, $number2) = explode(' ', $pos);

      if ($number1 > 0 && $number1 < 100){

        if ($number2 > 1 && $number2 < 10){

         echo $f->description. "<br>";

          }

        }

      }

    }

如果这个^^没有结果，我该怎么做，然后这样做：

    foreach(Feed('$url') as $f ) {

      if (strpos($f->title, $title) !== false){

             echo $f->description. "<br>";

              }

            }

我知道我可以使用 Len($variable) = 0 检查变量是否为空。但我没有变量。我怎么能得到这个？然后我想我可以这样做：

if (Len($variable) = 0) {

  foreach(Feed('$url') as $g ) {

    if (strpos($g->title, $title) !== false){

           echo $g->description. "<br>";

            }

          }

        } 

我想里面有可能foreach吗if？任何帮助是极大的赞赏！

Answer 1

您可以使用布尔变量来指示您是否以第一种方式找到了描述，如果没有，则以第二种方式找到它：$descriptionFound = false;foreach(Feed('https://www.vegvesen.no/trafikk/xml/savedsearch.rss?id=601') as $f) {&nbsp; if (strpos($f->title, $title) !== false){&nbsp; &nbsp; $pos = $f->children('georss', true)->children('gml', true)->children('gml', true);&nbsp; &nbsp; list($number1, $number2) = explode(' ', $pos);&nbsp; &nbsp; if (&nbsp; &nbsp; &nbsp; $number1 > 59.417104 && $number1 < 60.089568&nbsp; &nbsp; &nbsp; && $number2 > 5.115812 && $number2 < 7.811784&nbsp; &nbsp; ) {&nbsp; &nbsp; &nbsp; $descriptionFound = true;&nbsp; &nbsp; &nbsp; echo $f->description . "<br>";&nbsp; &nbsp; }&nbsp; }}if (!$descriptionFound) {&nbsp; foreach(Feed('https://www.vegvesen.no/trafikk/xml/savedsearch.rss?id=604') as $f) {&nbsp; &nbsp; if (strpos($f->title, $title) !== false){&nbsp; &nbsp; &nbsp; echo $f->description . "<br>";&nbsp; &nbsp; }&nbsp; }}同样，您可以在检查各种方法时存储描述，然后在最后输出值：$description = '';foreach(Feed('https://www.vegvesen.no/trafikk/xml/savedsearch.rss?id=601') as $f) {&nbsp; if (strpos($f->title, $title) !== false){&nbsp; &nbsp; $pos = $f->children('georss', true)->children('gml', true)->children('gml', true);&nbsp; &nbsp; list($number1, $number2) = explode(' ', $pos);&nbsp; &nbsp; if (&nbsp; &nbsp; &nbsp; $number1 > 59.417104 && $number1 < 60.089568&nbsp; &nbsp; &nbsp; && $number2 > 5.115812 && $number2 < 7.811784&nbsp; &nbsp; ) {&nbsp; &nbsp; &nbsp; $description .= $f->description . "<br>";&nbsp; &nbsp; }&nbsp; }}if (!$description) { //this will be falsy if it's an empty string, so no need to do == ''&nbsp; foreach(Feed('https://www.vegvesen.no/trafikk/xml/savedsearch.rss?id=604') as $f) {&nbsp; &nbsp; if (strpos($f->title, $title) !== false){&nbsp; &nbsp; &nbsp; $description .= $f->description . "<br>";&nbsp; &nbsp; }&nbsp; }}echo $description;要么会给你相同的代码流和最终结果。