blocks|key|1123222|text|你可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1123223|define(+'FOO',+'bar'+);

$constants+=+get_defined_constants(true);+//+the+true+argument+categorizes+the+constants
$constants+=+$constants[+'user'+];+//+this+gets+only+user-defined+constants

echo+"Hello,+my+name+is+{$constants['FOO']}";|code-block|syntax|javascript|1123224|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You could do:

<pre><code>define( 'FOO', 'bar' );

$constants = get_defined_constants(true); // the true argument categorizes the constants
$constants = $constants[ 'user' ]; // this gets only user-defined constants

echo "Hello, my name is {$constants['FOO']}";
</code></pre>

blocks|key|1338239|text|define('FOO',+'bar');
$constants+=+create_function('$a',+'return+$a;');
echo+"Hello,+my+name+is+{$constants(FOO)}";|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1338240|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>define('FOO', 'bar');
$constants = create_function('$a', 'return $a;');
echo "Hello, my name is {$constants(FOO)}";
</code></pre>

blocks|key|1123236|text|define(+'FOO',+'bar');++
$FOO+=+FOO;++
$string+=+"I+am+too+lazy+to+concatenate+$FOO+in+my+string";|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1123237|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>define( 'FOO', 'bar'); 
$FOO = FOO; 
$string = "I am too lazy to concatenate $FOO in my string";
</code></pre>

blocks|key|1338294|text|正如其他人指出的那样，你不能这样做。PHP有一个函数constant()，它不能直接在字符串中调用，但我们可以很容易地解决这个问题。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1338295|$constant+=+function($cons){
+++return+constant($cons);
};|code-block|syntax|javascript|1338296|关于它的用法有一个基本的例子：|1338297|define('FOO',+'Hello+World!');
echo+"The+string+says+{$constant('FOO')}";+|1338298|entityMap^0|Q|A|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

As others have pointed out you can not do that. PHP has a function <code>constant()</code> which cant be called directly in a string but we can easily work around this.

<pre><code>$constant = function($cons){
 return constant($cons);
};
</code></pre>

and a basic example on its usage:

<pre><code>define('FOO', 'Hello World!');
echo "The string says {$constant('FOO')}"; 
</code></pre>

blocks|key|1338327|text|我相信这回答了操作员最初的问题。唯一的问题是全局索引键似乎只在小写时起作用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1338328|define('DB_USER','root');
echo+"DB_USER=$GLOBALS[db_user]";|code-block|syntax|javascript|1338329|输出：|1338330|DB_USER=root|1338331|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I believe this answers the OP's original question. The only thing is the globals index key seems to only work as lower case.

<pre><code>define('DB_USER','root');
echo "DB_USER=$GLOBALS[db_user]";
</code></pre>

Output:

<pre><code>DB_USER=root
</code></pre>

blocks|key|1123381|text|有趣的是，您可以使用关键字'const‘作为您的函数的名称，以防止名称空间的垃圾：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1123382|define("FOO","foo");
${'const'}+=+function($a){return+$a;};
echo+"{$const(FOO)}";+//+Prints+"foo"
echo+const(FOO);+//+Parse+error:+syntax+error,+unexpected+T_CONST|code-block|syntax|javascript|1123383|您还可以使用$GLOBALS在整个代码中传播'const‘函数：|1123384|$GLOBALS['const']+=+function($a){return+$a;};|1123385|不确定它对于将来的使用是否安全。更糟糕的是，它看起来仍然很丑陋。|1123386|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

It is fun that you can use keyword 'const' as a name for your function to prevent namespace littering:

<pre><code>define("FOO","foo");
${'const'} = function($a){return $a;};
echo "{$const(FOO)}"; // Prints "foo"
echo const(FOO); // Parse error: syntax error, unexpected T_CONST
</code></pre>

You can also use $GLOBALS to propagate 'const' function all over the code:

<pre><code>$GLOBALS['const'] = function($a){return $a;};
</code></pre>

Unsure is it safe for future using. And what is worse - it's still looks ugly.

blocks|key|1338369|text|最简单的方法是|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1338370|define('MY_CONSTANT',+42);

$my_constant+=+MY_CONSTANT;
echo+"This+is+my+constant:+$my_constant";|code-block|syntax|javascript|1338371|使用(s)printf的另一种方式|offset|length|style|CODE|1338372|define('MY_CONSTANT',+42);

//+Note+that+%25d+is+for+numeric+values.+Use+%25s+when+constant+is+a+string++++
printf('This+is+my+constant:+%25d',+MY_CONSTANT);

//+Or+if+you+want+to+use+the+string.

$my_string+=+sprintf('This+is+my+constant:+%25d',+MY_CONSTANT);
echo+$my_string;|1338373|entityMap^0|0|0|2|9|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

The easiest way is

<pre><code>define('MY_CONSTANT', 42);

$my_constant = MY_CONSTANT;
echo "This is my constant: $my_constant";
</code></pre>

Another way using <code>(s)printf</code>

<pre><code>define('MY_CONSTANT', 42);

// Note that %d is for numeric values. Use %s when constant is a string 
printf('This is my constant: %d', MY_CONSTANT);

// Or if you want to use the string.

$my_string = sprintf('This is my constant: %d', MY_CONSTANT);
echo $my_string;
</code></pre>

blocks|key|1338385|text|我经常需要它，主要是在写脚本的时候，用来打印换行符。从浏览器运行脚本时，换行符应该是 ，从终端执行脚本时，换行符应该是PHP_EOL|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1338386|所以，我这样做：|1338387|$isCLI+=+(+php_sapi_name()+==+'cli'+);
$eol+=+$isCLI+?+PHP_EOL+:+' ';+
echo+"${eol}+This+is+going+to+be+printed+in+a+new+line";|code-block|syntax|javascript|1338388|entityMap^0|16|4|1Q|7|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|U|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

I need it pretty frequently, mostly while writing scripts, to print new line characters.
When running the script from browser, the newline should be <code>&lt;br&gt;</code> and while executing it from terminal it should be <code>PHP_EOL</code>
So, I do something like:
<pre><code>$isCLI = ( php_sapi_name() == 'cli' );
$eol = $isCLI ? PHP_EOL : '&lt;br&gt;'; 
echo &quot;${eol} This is going to be printed in a new line&quot;;
</code></pre>

Is there a way in PHP to include a constant in a string without concatenating?

<pre><code>define('MY_CONSTANT', 42);

echo "This is my constant: MY_CONSTANT";
</code></pre>

Include constant in string without concatenating

在PHP中有没有一种方法可以在字符串中包含常量而不进行连接？define('MY_CONSTANT', 42);echo "This is my constant: MY_CONSTANT";

问在字符串中包含常量而不进行连接
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在字符串中包含常量而不进行连接EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问在字符串中包含常量而不进行连接
EN