Question

我正在尝试构建一个天气刮板应用程序。出于某种原因，这个PHP代码给了我错误

$city = $_GET['city'];    
$city = str_replace(" ","",$city);
$contents = file_get_contents("http://www.weather-forecast.com/locations/".$city."/forecasts/latest");

preg_match('/3 Day Weather Forecast Summary:<\/b><span class="read-more-small"><span class="read-more-content"> <span class="phrase">(.*?)</s',$contents,$matches);    //use single quotes ' " " ' if double quotes are inside

echo($matches[0]);

如果我没有输入city = new york，那么会给我以下错误，如果我拼写错误的城市名称，它会给我同样的错误，因为$city是空的，有错误的值...是有没有办法解决它？

Live example

Answer 1

$city=!empty( $_GET['city'] ) ? $_GET['city'] : false;
if( $city ){

    $city=str_replace( " ", "", $city );

    $contents=@file_get_contents( "http://www.weather-forecast.com/locations/".$city."/forecasts/latest" );
    if( $contents ){
        preg_match('/3 Day Weather Forecast Summary:<\/b><span class="read-more-small"><span class="read-more-content"> <span class="phrase">(.*?)</s',$contents,$matches);    //use single quotes ' " " ' if double quotes are inside
        echo($matches[0]);
    } else {
        echo "Bad foo!";
    }
} else {
    echo "No city";
}

正如@jan所示，我也认为DOMDocument＆amp; DOMXPath为preg_match ...

提供了更强大的解决方案

$city=!empty( $_GET['city'] ) ? $_GET['city'] : false;
if( $city ){

    $city=str_replace( " ", "", $city );
    $url="http://www.weather-forecast.com/locations/{$city}/forecasts/latest";

    $contents=@file_get_contents( $url );
    if( $contents ){

        $dom=new DOMDocument;
        $dom->loadHTML($contents);
        $xp=new DOMXPath($dom);

        $col=$xp->query('//div[@class="forecast-content"]/p[@class="summary"]/span/span/span');
        foreach($col as $node){
            $header=$node->parentNode->parentNode->parentNode->firstChild->nodeValue;
            $description=$node->nodeValue;
            echo  '<h4>' . $header . '</h4><div>' . $description . '</div>';
        }
    } else {
        echo "Bad foo!";
    }
} else {
    echo "No city";
}

Answer 2

问题是：为什么？ ...而不是使用DOM parser 例如。对于古老的德国可爱的首都：

<?php

$url = 'http://www.weather-forecast.com/locations/Berlin/forecasts/latest';
$html = file_get_contents($url);

$dom = new DOMDocument();
libxml_use_internal_errors(true);
$dom->loadHTML($html);
libxml_clear_errors();
$xpath = new DOMXPath($dom);

$text = $xpath->query("//p[@class='summary'][1]//span[@class = 'phrase']");
echo $text->item(0)->textContent;
?>

脚本返回Mostly dry. Warm (max 25°C on Wed afternoon, min 11°C on Mon night). Wind will be generally light. 要获得所有预测，请省略[1]并循环结果。

php代码在尝试将变量放入文件路径时出错

2 个答案: