PHP If / Else语句在While循环中不起作用 [英] PHP If / Else statement not working in While loop

问题描述

我一直在研究这段代码大约一个小时，似乎无法弄清楚它为什么不起作用。 PHP允许在While循环中使用If / Else语句吗？我尝试在If / Else语句中添加不同的回声，后者（Else）不会显示。这是因为我试图使用相同的变量名称吗？

I've been working on this bit of code for about an hour and can't seem to figure out why it's not working. Does PHP allow If/Else statements within While loops? I've tried adding different echos to both If/Else statements and the latter (Else) will not show. Is this because I'm trying to use the same variable names?

while($row = mysql_fetch_array($result))

{

//assign variables
$title = $row['title'];
$file_url = $row['file_location'];
$category = $row['category'];
$layout = $row['layout'];


    If ($layout = "vertical")       
    {
        //Page Layout
        $BODYLAYOUT = "vertical_body";
        $GAMECONTAIN = "vertical_gameContain";
        $GAMEWIDTH = "vertical_game";
    }
    Else
    {
        // Page Layout
        $BODYLAYOUT = "horizontal_body";
        $GAMECONTAIN = "horizontal_gameContain";
        $GAMEWIDTH = "horizontal_game";
    }

推荐答案

if ($layout = "vertical")   

应为：

if ($layout == "vertical")   

否则你正在为'vertical'布局值，而不是比较它的值，看它是否等于'vertical'。否则该分配将等于true，因为第一部分运行而ELSE没有。

Otherwise you are assinging a value to $layout of 'vertical' opposed to comparing it's value to see if it's equal to 'vertical'. That assignment will otherwise equal to true, reason the first part runs and the ELSE does not.

我用来防止这样的事故的一种方法是将常数放在第一部分as：

One method I use to prevent accidents like this is to put the constant first such as:

if ("vertical" == $layout)   

这样，如果我错过了其他=符号PHP会出错，而不是错误地分配值。

That way if I miss the other = sign PHP will error, rather than assign the value erroneously.

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