PHP：在双引号内使用变量
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PHP: Using a variable inside a double quotes
提问by black_belt
please check the following code.
请检查以下代码。
$imagebaseurl = 'support/content_editor/uploads/$name';
The $imagebaseurlis a variable that is containing a link to my image folder (uploads) and inside the folder I have some other folders which are named after my users name. for example: I have a user who's name is john, so the the link should look like this-> support/content_editor/uploads/john.
这$imagebaseurl是一个变量，其中包含指向我的图像文件夹（上传）的链接，并且在文件夹内我还有一些其他文件夹，这些文件夹以我的用户名命名。例如：我有一个名为 john 的用户，因此链接应如下所示 -> support/content_editor/uploads/john。
The main idea is when any user is logged in and browses his image gallery I want to take him to his own gallery which basically is named after his name.
主要思想是当任何用户登录并浏览他的图片库时，我想带他到他自己的画廊，该画廊基本上以他的名字命名。
When he will visit the gallery the value of $namein the link will come from the user's login name (from session). Now the problem is as you probably have already understood that the placement of $namein the above link is wrong and that is why it is not working. I am getting this whole URL> (support/content_editor/uploads/$name) instead of (support/content_editor/uploads/john)
当他访问图库$name时，链接中的值将来自用户的登录名（来自会话）。现在的问题是，您可能已经明白，$name上面链接中的位置是错误的，这就是它不起作用的原因。我得到了整个 URL> (support/content_editor/uploads/$name) 而不是 (support/content_editor/uploads/john)
Now could you please tell me how to use the $namein this $imagebaseurl = 'support/content_editor/uploads/$name';
现在，请你告诉我如何使用$name这个$imagebaseurl = 'support/content_editor/uploads/$name';
回答by rid
$imagebaseurl = 'support/content_editor/uploads/' . $name;
or
或者
$imagebaseurl = "support/content_editor/uploads/{$name}";
Note that if you use double quotes, you can also write the above as:
注意，如果使用双引号，也可以将上面的写成：
$imagebaseurl = "support/content_editor/uploads/$name";
It's good though to get in the habit of using {$...}in double quotes instead of only $..., for times where you need to insert the variable in a string where it's not obvious to PHP which part is the variable and which part is the string.
养成使用{$...}双引号而不是仅使用双引号的习惯是件好事$...，因为有时您需要将变量插入字符串中，而 PHP 不清楚哪部分是变量，哪部分是字符串。
If you want the best performance, use string concatenation with single quotes.
如果您想要最佳性能，请使用带单引号的字符串连接。
回答by HumbleWebDev
I couldn't disagree more with the previous post.
我不能更不同意上一篇文章。
I'd almost go as far to call it bad practice to use
我几乎会说使用它是不好的做法
$varname = 'EXAMPLE';
$fulltext = "This is an $varname";
Its more maintainable, from my experience, to utilize a good friend of mine known as sprintf();
根据我的经验，使用我的一个好朋友 sprintf() 更易于维护；
define('CONST_NAME', 'This is an example of a better %s');
define('EXAMPLE', sprintf(CONST_NAME, 'practice'));
echo EXAMPLE;
Why? The first one may seem more clear, but the second one is much more re-usable. I recommend utilizing sprintf over the php magic double quote nonesense which exists, literally, in NO other language.
为什么？第一个可能看起来更清晰，但第二个更易于重复使用。我建议在 php 魔术双引号废话上使用 sprintf，从字面上看，它不存在于其他语言中。
http://php.net/manual/en/function.sprintf.php
http://php.net/manual/en/function.sprintf.php
This is also the practice used very similar to C#, and many other languages.
这也是与 C# 和许多其他语言非常相似的做法。
See also: https://msdn.microsoft.com/en-us/library/system.string.format(v=vs.110).aspx
另见：https: //msdn.microsoft.com/en-us/library/system.string.format(v=vs.110).aspx
