而foreach循环输出两次 - while foreach loop is outputting twice

while foreach loop is outputting twice

本文关键字：两次 foreach 循环输出 | 更新日期: 2023-09-27

我希望循环只输出一次。相反，它输出两次。这是代码：

$results = mysql_query($query);
    while ($c = mysql_fetch_array($results)){
        $individualPostcode = explode(",", $c['postcode']);
        foreach($individualPostcode as $val){ 
            $val = trim($val); //Get rid of spaces
            if($val === $postcode){
                echo $c['url']."<br>";
            }
        }
    }
}

这是输出：

http://www.dyno.com/home-security/local-experts/greater-london/dyno-locks-and-alarms-enfield
http://www.dyno.com/home-security/local-experts/greater-london/dyno-locks--alarms-enfield
http://www.dyno.com/home-security/local-experts/greater-london/dyno-locks-and-alarms-enfield
http://www.dyno.com/home-security/local-experts/greater-london/dyno-locks--alarms-enfield

我已经尝试过去掉foreach循环，但我需要根据用户输入检查该数组。

这是$postcode:的初始化

$userInput = $_POST["input"];
if(strlen($userInput) < 4) 
    echo "User Input : ".$userInput."<br>";
else //Below gets the first three chars of the users string
    echo "User Input : $userInput<br>What is being used : ".mb_substr($userInput, 0, 3)."<br>";
$postcode = mb_substr($userInput, 0, 3);

您可以始终创建URL的数组，通过检查URL是否已放入数组来阻止它们复制：

$results = mysql_query($query);
$urlsArr = array();
while ($c = mysql_fetch_array($results)){
    $individualPostcode = explode(",", $c['postcode']);
    foreach($individualPostcode as $val){ 
        $val = trim($val); //Get rid of spaces
        if($val === $postcode){
            if (!in_array($c['url'], $urlsArr)) echo $c['url']."<br>";
            $urlsArr[] = $c['url'];
        }
    }
}

mysql_fetch_array为每个返回的结果返回一个关联数组和索引数组。foreach循环将在两者上循环并输出两次。尝试使用mysql_fetch_assoc()

http://php.net/manual/en/function.mysql-fetch-array.php

更好的做法是，尝试转到mysqli类。它的速度更快，mysql被去复杂化。

http://php.net/manual/en/intro.mysqli.php