Question

从这里开始是程序员，所以我很抱歉，如果这浪费您的时间。

我制作了一个如下所示的HTML表单：

<form action="post.php" method="post">
    <label for="artist">Artist:</label><br>
    <input title="" type="text" name="artist" id="artist" value="Muse" required><br>
    <label for="album">Album:</label><br>
    <input title="" type="text" name="album" id="album" value="Live At Rome Olympic Stadium" required><br>
    <label for="genre">Genre:</label><br>
    <input title="" type="text" name="genre" id="genre" value="Rock" required><br>
    <label for="year">Year:</label><br>
    <input title="" type="number" name="year" id="year" value="2013" required><br>
    <label for="tracks">Tracks:</label><br>
    <input title="" type="number" name="tracks" id="tracks" value="13" required><br><br>
    <input title="" type="submit" name="submit" value="Submit">
</form>

提交的信息将发送到post.php，如下所示：

if ($_POST['artist'] ['album'] ['genre'] ['year'] ['tracks']) {
    echo "The artist name is " . $_POST['artist'];
    echo "<br>";
    echo "The album name is " . $_POST['album'];
    echo "<br>";
    echo "The genre is " . $_POST['genre'];
    echo "<br>";
    echo "The year of release is " . $_POST['year'];
    echo "<br>";
    echo "The number of tracks is " . $_POST['tracks'];
    echo "<br>";
} else {
    echo "You have not filled out all the forms";
}

（我不确定是否使用isset，但这是另一回事）

根据我的编辑器PHPStorm，$ _ POST中的参数格式没有错误，但是我的浏览器给我以下错误：

警告：第3行的C：\ xampp \ htdocs \ php1 \ week2test \ week2music \ post.php中的字符串偏移量'album'

警告：第3行上C：\ xampp \ htdocs \ php1 \ week2test \ week2music \ post.php中的字符串偏移'genre'非法

警告：第3行的C：\ xampp \ htdocs \ php1 \ week2test \ week2music \ post.php中的字符串偏移量'year'

警告：第3行的C：\ xampp \ htdocs \ php1 \ week2test \ week2music \ post.php中的字符串偏移量'tracks'非法

我应该如何在$ _POST中设置参数格式以消除这些错误？或者，如果这不是问题所在，那么我不知道问题出在哪里，您有见识吗？

在这种情况下我应该使用isset吗？

谢谢。

Answer 1

if ($_POST['artist'] ['album'] ['genre'] ['year'] ['tracks'])在您当前的上下文中不存在，这将是一个5深度的数组。

您的意思是if ($_POST['artist'] && $_POST['album'] && $_POST['genre'] && $_POST['year'] && $_POST['tracks'])

或者，甚至更好的是，使用isset()：if (isset($_POST['artist']) && isset($_POST['album']) && isset($_POST['genre']) && isset($_POST['year']) && isset($_POST['tracks']))

但是我更喜欢使用更性感的解决方案，将要检查的$_POST的密钥存储在数组中，然后在该数组上循环：

$KeysToCheck = array('artist', 'album', 'genre', 'year', 'tracks');
$AllFieldsAreGood = true;

foreach($KeysToCheck as $KeyToCheck)
    if (!isset($_POST[$KeyToCheck]))
        $AllFieldsAreGood = false;

if (!$AllFieldsAreGood)
    echo "You have not filled out all the forms";
else
{
    // success ! Manage it.
}

请注意，仅在选中复选框时使用isset()就是true。

Answer 2

如果要使用从POST接收到的非NULL值，最好使用isset

import scrapy


class MarketSpider(scrapy.Spider):
    name = 'market'
    allowed_domains = ['coinmarketcap.com']
    start_urls = ['http://coinmarketcap.com/']
    def parse(self, response):
        Coin = response.xpath('//*[@class="currency-name-container link-secondary"]/@href').extract()
        for link in Coin:
            absolute_url = response.urljoin(link)
            yield scrapy.Request(absolute_url,callback=self.website_link)
    def website_link(self,response):
        link = response.xpath('//*[@class="list-unstyled details-panel-item--links"]/li[2]/a/@href').extract()
        name = response.xpath('normalize-space(//h1)').extract()
        yield{'Name': name ,'Link': link}

Answer 3

isset()用于检查变量是否存在，并且不为空。

因此，始终首选使用它。就您而言，它可以像这样使用：

if (isset($_POST['artist']) && isset($_POST['album']) && isset($_POST['genre']) && isset($_POST['year']) && isset($_POST['tracks'])) {
    echo "The artist name is " . $_POST['artist'];
    echo "<br>";
    echo "The album name is " . $_POST['album'];
    echo "<br>";
    echo "The genre is " . $_POST['genre'];
    echo "<br>";
    echo "The year of release is " . $_POST['year'];
    echo "<br>";
    echo "The number of tracks is " . $_POST['tracks'];
    echo "<br>";
} else {
    echo "You have not filled out all the forms";
}

如何在$ _POST

3 个答案: