blocks|key|5703711|text|停!|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5703712|你正在看的教程已经严重过时了！+。它们不再被维护，deprecation+process已经开始对其进行维护。看到了吗？相反，学习，并使用PDO或MySQLi+-+this+article将帮助您决定使用哪种方法。如果你选择PDO，here+is+a+good+tutorial。|offset|length|5703713|5703714|至于具体的问题，这行|5703715|while+($post+=+mysql_fetch_assoc($query))+{|code-block|syntax|javascript|5703716|就是这个条件。如果有更多的结果，则mysql_fetch_assoc()返回一个数组；如果没有结果，则返回false。如果返回false，则条件的计算结果为false，循环将中断。|style|CODE|5703717|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/q/12859942/|1|http://news.php.net/php.internals/53799|2|http://php.net/pdo|3|http://php.net/mysqli|4|https://php.net/manual/en/mysqlinfo.api.choosing.php|5|http://wiki.hashphp.org/PDO_Tutorial_for_MySQL_Developers^0|0|F|1|0|P|J|1|1X|3|2|21|6|3|2A|C|4|38|N|5|0|0|0|0|H|J|1H|5|1R|5|26|5|0^^$0|@$1|2|3|4|5|6|7|19|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1A|8|@]|9|@$D|1B|E|1C|1|1D]|$D|1E|E|1F|1|1G]|$D|1H|E|1I|1|1J]|$D|1K|E|1L|1|1M]|$D|1N|E|1O|1|1P]|$D|1Q|E|1R|1|1S]]|A|$]]|$1|F|3|-4|5|6|7|1T|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|1U|8|@]|9|@]|A|$]]|$1|I|3|J|5|K|7|1V|8|@]|9|@]|A|$L|M]]|$1|N|3|O|5|6|7|1W|8|@$D|1X|E|1Y|P|Q]|$D|1Z|E|20|P|Q]|$D|21|E|22|P|Q]|$D|23|E|24|P|Q]]|9|@]|A|$]]|$1|R|3|-4|5|6|7|25|8|@]|9|@]|A|$]]]|S|$T|$5|U|V|W|A|$X|Y]]|Z|$5|U|V|W|A|$X|10]]|11|$5|U|V|W|A|$X|12]]|13|$5|U|V|W|A|$X|14]]|15|$5|U|V|W|A|$X|16]]|17|$5|U|V|W|A|$X|18]]]]

<h2>STOP!</h2>

The tutorial you're watching is severely outdated! <a href="https://stackoverflow.com/q/12859942/">Please, don't use <code>mysql_*</code> functions in new code</a>. They are no longer maintained and the <a href="http://news.php.net/php.internals/53799" rel="nofollow noreferrer">deprecation process</a> has begun on it. See the <a href="https://www.php.net/manual/en/function.mysql-connect.php" rel="nofollow noreferrer">red box</a>? Learn about <a href="https://en.wikipedia.org/wiki/Prepared_statement" rel="nofollow noreferrer">prepared statements</a> instead, and use <a href="http://php.net/pdo" rel="nofollow noreferrer">PDO</a> or <a href="http://php.net/mysqli" rel="nofollow noreferrer">MySQLi</a> - <a href="https://php.net/manual/en/mysqlinfo.api.choosing.php" rel="nofollow noreferrer">this article</a> will help you decide which. If you choose PDO, <a href="http://wiki.hashphp.org/PDO_Tutorial_for_MySQL_Developers" rel="nofollow noreferrer">here is a good tutorial</a>.

<hr>

As for the specific question, this line

<pre><code>while ($post = mysql_fetch_assoc($query)) {
</code></pre>

Is the condition. <code>mysql_fetch_assoc()</code> returns an array if there are more results, and <code>false</code>, in the case there aren't any. If it returns <code>false</code>, the condition will evaluate to <code>false</code> and the loop would break.

blocks|key|3976590|text|基本上，您正在获取新行，并使用以下命令将其赋给$post变量：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3976591|while+($post+=+mysql_fetch_assoc($query))|code-block|syntax|javascript|3976592|mysql_fetch_assoc|3976593|3976594|返回值|blockquote|3976595|3976596|返回与提取的行对应的字符串数组，如果没有更多的行，则返回FALSE。|BOLD|3976597|3976598|因此，当mysql_fetch_assoc返回false时，它被赋值给$post变量，然后在while中进行求值，然后循环停止。|3976599|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/manual/en/function.mysql-fetch-assoc.php^0|N|5|0|0|0|H|0|0|0|0|0|S|5|0|0|4|H|N|5|Z|5|1A|5|0^^$0|@$1|2|3|4|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|18|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|19|8|@]|D|@$9|1A|A|1B|1|1C]]|E|$]]|$1|M|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]|$1|N|3|O|5|P|7|1E|8|@]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]|$1|R|3|S|5|6|7|1G|8|@$9|1H|A|1I|B|T]]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1J|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|1K|8|@$9|1L|A|1M|B|C]|$9|1N|A|1O|B|C]|$9|1P|A|1Q|B|C]|$9|1R|A|1S|B|C]]|D|@]|E|$]]|$1|X|3|-4|5|6|7|1T|8|@]|D|@]|E|$]]]|Y|$Z|$5|10|11|12|E|$13|14]]]]

Basicaly you are fetching new row and assigning it to <code>$post</code> variable with:

<pre><code>while ($post = mysql_fetch_assoc($query))
</code></pre>

<a href="http://php.net/manual/en/function.mysql-fetch-assoc.php" rel="nofollow">mysql_fetch_assoc</a>:

<blockquote>
 Return Values
 
 Returns an associative array of strings that corresponds to the
 fetched row, or FALSE if there are no more rows.
</blockquote>

So when <code>mysql_fetch_assoc</code> returns <code>false</code> it is assigned to <code>$post</code> variable and then it is evaluated within <code>while</code>, then loop stops.

blocks|key|3493590|text|如mysql_fetch_assoc手册页所述|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3493591|3493592|返回值:返回与提取的行相对应的字符串数组，如果没有更多的行，则返回FALSE。|blockquote|3493593|3493594|entityMap|0|LINK|mutability|MUTABLE|url|http://php.net/mysql_fetch_assoc^0|1|H|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|-4|5|6|7|U|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|V|8|@]|9|@]|C|$]]|$1|H|3|-4|5|6|7|W|8|@]|9|@]|C|$]]|$1|I|3|-4|5|6|7|X|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

As explained on the manual page for <a href="http://php.net/mysql_fetch_assoc" rel="nofollow">mysql_fetch_assoc</a>:

<blockquote>
 Return values: Returns an associative array of strings that
 corresponds to the fetched row, or FALSE if there are no more rows.
</blockquote>

blocks|key|3493615|text|while+($post+=+mysql_fetch_assoc($query))|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3493616|表示第一个$post获得一个值。当出现错误时，mysql_fetch_assoc返回false。|unstyled|3493617|while循环检查$post是否为假，它可以是true、整数、数组等。|3493618|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>while ($post = mysql_fetch_assoc($query))
</code></pre>

Means first $post gets a value. mysql_fetch_assoc returns false when there is an error.

The while loop checks that $post is not false, it can be true, an integer, an array, etc.

blocks|key|145188|text|它是PHP的一部分。赋值的结果是被赋值。这允许这样的事情：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|145189|$x+=+$y+=+$z+=+7;|code-block|syntax|javascript|145190|它将7赋值给所有3个变量。因此，给出了|offset|length|style|CODE|145191|while($row+=+mysql_result(...))+{|145192|当没有更多的数据需要获取时，mysql_result将返回一个行数据数组或一个布尔值false。该数组/布尔值被赋值给$row。由于此赋值包含了while()，因此数组/布尔值会向上传播到while()。|145193|如果您得到一行数据，那么它就是一个被while视为布尔值true的数组，然后循环继续。如果没有更多的数据，mysql_fetch将返回一个布尔值false，该值被赋值给$row，这个false也是赋值的结果，这意味着while()得到一个FALSE，然后循环终止。|145194|entityMap^0|0|0|2|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|11|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

It's part of PHP. The result of an assignment is the value being assigned. That allows things like:

<pre><code>$x = $y = $z = 7;
</code></pre>

which assigns <code>7</code> to all 3 variables. As such, given

<pre><code>while($row = mysql_result(...)) {
</code></pre>

mysql_result will return an array of row data or a boolean false when there's no more data to fetch. That array/boolean is assigned to $row. And since this assignment has the while() wrapped around it, the array/boolean propagates up to the while().

If you get a row of data back, it's an array which is treated as a boolean true by the while, and the loop continues. If there's no more data, mysql_fetch returns a boolean false, which is assigned to $row, and that false is also the result of the assignment, meaning while() gets a FALSE, and the loop terminates.

So, I'm building my first super basic CMS using PHP. I don't want to simply copy the code from the tutorial I'm watching, but really understand it. One thing that bothers me is the use of the while loop for fetching posts. In the code below, I can't see how the statement inside within the rounded brackets constitute a condition. Seems to me all it does is assigning an array to the variable $post. How can you loop over something that is not a condition is my question, I suppose. Thanks!

<pre><code>function get_posts () {
 $query = mysql_query("SELECT * FROM posts") or die(mysql_error());

 while ($post = mysql_fetch_assoc($query)) {
 echo $post['Content'];
 }
}
</code></pre>

No condition in PHP while loop?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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因此，我正在使用PHP构建我的第一个超级基本的CMS。我不想简单地复制我正在看的教程中的代码，而是真正理解它。有一件事困扰着我，那就是使用while循环来获取帖子。在下面的代码中，我看不到圆括号内的语句如何构成条件。在我看来，它所做的一切就是将一个数组赋给变量$post。我想，我的问题是，你如何循环不是条件的东西。谢谢!function get_posts () {   $query = mysq

问PHP while循环中没有条件？
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