Question

当我将foreach循环放在for循环范围之外时，它似乎不起作用。
我在这做错了什么：

<?php
$allUrls = array();

for( $i = 0; $i <= 1; $i++ ) {

    $html = file_get_contents("http://www.keurmerk.info/Leden_Partners?s=&c=0&Page=".$i."");
    $pattern = "/(http(s)?:\/\/)?(w{3}\.)(\w+\.)([a-zA-Z]{2,6})(\/\w*)?/";
    preg_match_all( $pattern, $html, $urls );

    if ($i == 0) $allUrls[0] = $urls[0];
    else $allUrls[0] .= $urls[0];

}           

foreach ( $allUrls[0] as $url ) {
    echo $url . '<br>'; 
}
?>

如果我这样做：

<?php
for( $i = 0; $i <= 1; $i++ ) {

    $html = file_get_contents("http://www.keurmerk.info/Leden_Partners?s=&c=0&Page=".$i."");
    $pattern = "/(http(s)?:\/\/)?(w{3}\.)(\w+\.)([a-zA-Z]{2,6})(\/\w*)?/";
    preg_match_all( $pattern, $html, $urls );
    $allUrls[0] = $urls[0];
    foreach ( $allUrls[0] as $url ) {
        echo $url . '<br>';
    }
}
?>

然后它似乎有效。

Answer 1

改变这个：

$allUrls[0][] = $urls[0];

所以整个代码将是：

$allUrls = array();

for( $i = 0; $i <= 1; $i++ ) {

    $html = file_get_contents("http://www.keurmerk.info/Leden_Partners?s=&c=0&Page=".$i."");
    $pattern = "/(http(s)?:\/\/)?(w{3}\.)(\w+\.)([a-zA-Z]{2,6})(\/\w*)?/";
    preg_match_all( $pattern, $html, $urls );

    $allUrls[$i] = $urls[0];

}           

foreach ( $allUrls as &$url ) {
    echo $url . '<br>'; 
}

Answer 2

$allUrls[0] .= $urls[0];

表示将该值附加到数组的第一个元素，这就像添加到值末尾的字符串一样。如果需要向该数组添加新值（子数组位于第0位），请使用此表示法

$allUrls[0][] = $urls[0];

然而，根本不需要那个子阵列。你可以简单地删除这个

if ($i == 0) $allUrls[0] = $urls[0];
else $allUrls[0] .= $urls[0];

并使用

 $allUrls[]=$urls[0];

只需像

一样循环播放

foreach ( $allUrls as $url ) {
    echo $url . '<br>'; 
}

Answer 3

$allUrls = array();
 for( $i = 0; $i <= 1; $i++ ) {

$html = file_get_contents("http://www.keurmerk.info/Leden_Partners?s=&c=0&Page=".$i."");
$pattern = "/(http(s)?:\/\/)?(w{3}\.)(\w+\.)([a-zA-Z]{2,6})(\/\w*)?/";
preg_match_all( $pattern, $html, $urls );

$allUrls[$i] = $urls[0]


}           

foreach ( $allUrls as $url ) {
    echo $url . '<br>'; 
}

试试这个。

Answer 4

您可以使用以下功能执行此操作：

function parseMyUrl($pageNo) {
    $html = file_get_contents("http://www.keurmerk.info/Leden_Partners?s=&c=0&Page=". $pageNo);
    $pattern = "/(http(s)?:\/\/)?(w{3}\.)(\w+\.)([a-zA-Z]{2,6})(\/\w*)?/";
    preg_match_all($pattern, $html, $urls);
    if ($urls[0])
        return $urls[0];
    else
        return array();
}

用法：

var_dump(parseMyUrl(1));
var_dump(parseMyUrl(2));

输出：

array (size=21)
  0 => string 'http://www.bikinisonline.eu' (length=27)
  1 => string 'http://www.handpoppen.net' (length=25)
  2 => string 'http://www.123kinderfietsen.nl' (length=30)
  3 => string 'http://www.123ledspots.nl' (length=25)
  4 => string 'http://www.123mijngordijn.nl' (length=28)
  5 => string 'http://www.123soatest.nl' (length=24)
  6 => string 'http://www.123sportfietsen.nl' (length=29)
  7 => string 'http://www.123superfoods.nl' (length=27)
  8 => string 'http://www.123telefoon.nl' (length=25)
  9 => string 'http://www.123tuinleds.nl' (length=25)
  10 => string 'http://www.123voetmassage.nl' (length=28)
  11 => string 'http://www.12cook.com' (length=21)
  12 => string 'http://www.1gameshop.be' (length=23)
  13 => string 'http://www.24parfums.nl' (length=23)
  14 => string 'http://www.2wielerwinkel.nl' (length=27)
  15 => string 'http://www.4activekidz.nl' (length=25)
  16 => string 'http://www.4kidsathome.nl' (length=25)
  17 => string 'http://www.4kidsnederland.nl' (length=28)
  18 => string 'http://www.4moregames.nl' (length=24)
  19 => string 'http://www.4sporters.nl' (length=23)
  20 => string 'https://www.extremetracking.com' (length=31)

array (size=19)
  0 => string 'http://www.goedkopesneeuwkettingen.nl' (length=37)
  1 => string 'http://www.bikinisonline.eu' (length=27)
  2 => string 'http://www.villatotaal.nl' (length=25)
  3 => string 'http://www.4yoursport.nl' (length=24)
  4 => string 'http://www.4youwear.nl' (length=22)
  5 => string 'http://www.6566.eu' (length=18)
  6 => string 'http://www.aadenwijn.nl' (length=23)
  7 => string 'http://www.aagifts.nl' (length=21)
  8 => string 'http://www.aanhangershop.nl' (length=27)
  9 => string 'http://www.aanhangwagendirect.nl' (length=32)
  10 => string 'http://www.aannemerskorting.nl' (length=30)
  11 => string 'http://www.abcoparts.nl' (length=23)
  12 => string 'http://www.aboutshoes.nl' (length=24)
  13 => string 'http://www.accudienst.nl/' (length=25)
  14 => string 'http://www.acculaptop.com' (length=25)
  15 => string 'http://www.accuserviceholland.nl' (length=32)
  16 => string 'http://www.accushop.nl' (length=22)
  17 => string 'http://www.accuweb.nl' (length=21)
  18 => string 'https://www.extremetracking.com' (length=31)

现在，如果你想在循环中使用它......你可以用一种漂亮而干净的方式来做到这一点：

for ($i = 0; $i <= 1; $i++) {
    $urls = parseMyUrl($i);
    foreach ($urls as $url) {
        echo $url . '<br>';
    }
}

如何使用数组外部范围

4 个答案: