假设我有这样的PHP代码:

$FooBar = "a string";

然后我需要一个这样的函数:

print_var_name($FooBar);

打印:

FooBar

有什么想法如何实现这一点?这在PHP中可能吗?


当前回答

从php.net

@Alexandre -简短的解决方案

<?php
function vname(&$var, $scope=0)
{
    $old = $var;
    if (($key = array_search($var = 'unique'.rand().'value', !$scope ? $GLOBALS : $scope)) && $var = $old) return $key;  
}
?>

@Lucas - usage

<?php
//1.  Use of a variable contained in the global scope (default):
  $my_global_variable = "My global string.";
  echo vname($my_global_variable); // Outputs:  my_global_variable

//2.  Use of a local variable:
  function my_local_func()
  {
    $my_local_variable = "My local string.";
    return vname($my_local_variable, get_defined_vars());
  }
  echo my_local_func(); // Outputs: my_local_variable

//3.  Use of an object property:
  class myclass
  {
    public function __constructor()
    {
      $this->my_object_property = "My object property  string.";
    }
  }
  $obj = new myclass;
  echo vname($obj->my_object_property, $obj); // Outputs: my_object_property
?>

其他回答

我真的看不出用例……如果你将输入print_var_name($foobar)什么那么难(和不同)输入打印(“foobar”)代替?

因为即使你要在函数中使用这个,你也会得到变量的本地名称…

无论如何,这是反射手册,以防你需要什么。

出于调试的原因,我做了一个检查函数。它就像print_r()的类固醇,很像Krumo,但对对象更有效一点。我想添加var名称检测,灵感来自于Nick Presta的帖子。它检测作为参数传递的任何表达式,而不仅仅是变量名。

这只是检测传递表达式的包装器函数。 大多数案子都没问题。 如果在同一行代码中多次调用该函数,则它将不起作用。

这很好: 死(检查($ this - > getUser()——> hasCredential(“删除”)));

Inspect()是检测传递表达式的函数。

我们得到:$this->getUser()->hasCredential("delete")

function inspect($label, $value = "__undefin_e_d__")
{
    if($value == "__undefin_e_d__") {

        /* The first argument is not the label but the 
           variable to inspect itself, so we need a label.
           Let's try to find out it's name by peeking at 
           the source code. 
        */

        /* The reason for using an exotic string like 
           "__undefin_e_d__" instead of NULL here is that 
           inspected variables can also be NULL and I want 
           to inspect them anyway.
        */

        $value = $label;

        $bt = debug_backtrace();
        $src = file($bt[0]["file"]);
        $line = $src[ $bt[0]['line'] - 1 ];

        // let's match the function call and the last closing bracket
        preg_match( "#inspect\((.+)\)#", $line, $match );

        /* let's count brackets to see how many of them actually belongs 
           to the var name
           Eg:   die(inspect($this->getUser()->hasCredential("delete")));
                  We want:   $this->getUser()->hasCredential("delete")
        */
        $max = strlen($match[1]);
        $varname = "";
        $c = 0;
        for($i = 0; $i < $max; $i++){
            if(     $match[1]{$i} == "(" ) $c++;
            elseif( $match[1]{$i} == ")" ) $c--;
            if($c < 0) break;
            $varname .=  $match[1]{$i};
        }
        $label = $varname;
    }

    // $label now holds the name of the passed variable ($ included)
    // Eg:   inspect($hello) 
    //             => $label = "$hello"
    // or the whole expression evaluated
    // Eg:   inspect($this->getUser()->hasCredential("delete"))
    //             => $label = "$this->getUser()->hasCredential(\"delete\")"

    // now the actual function call to the inspector method, 
    // passing the var name as the label:

      // return dInspect::dump($label, $val);
         // UPDATE: I commented this line because people got confused about 
         // the dInspect class, wich has nothing to do with the issue here.

    echo("The label is: ".$label);
    echo("The value is: ".$value);

}

下面是inspector函数(和我的dInspect类)的一个例子:

http://inspect.ip1.cc

该页面的文本是西班牙语,但代码简洁,非常容易理解。

我知道这个问题很老了,而且已经有人回答了,但我其实是在找这个。我把这个答案贴出来是为了给大家节省一点时间来完善一些答案。

选项1:

$data = array('$FooBar');  

$vars = [];  
$vars = preg_replace('/^\\$/', '', $data); 

$varname = key(compact($vars));  
echo $varname;

打印:

FooBar

不管出于什么原因,你会发现自己处于这样的情况下,它确实有效。

. 选项2:

$FooBar = "a string";  

$varname = trim(array_search($FooBar, $GLOBALS), " \t.");  
echo $varname;

如果$FooBar拥有一个唯一的值,它将打印'FooBar'。如果$FooBar为空或空,它将打印找到的第一个空字符串或空字符串的名称。

它可以这样使用:

if (isset($FooBar) && !is_null($FooBar) && !empty($FooBar)) {
    $FooBar = "a string";
    $varname = trim(array_search($FooBar, $GLOBALS), " \t.");
}

从php.net

@Alexandre -简短的解决方案

<?php
function vname(&$var, $scope=0)
{
    $old = $var;
    if (($key = array_search($var = 'unique'.rand().'value', !$scope ? $GLOBALS : $scope)) && $var = $old) return $key;  
}
?>

@Lucas - usage

<?php
//1.  Use of a variable contained in the global scope (default):
  $my_global_variable = "My global string.";
  echo vname($my_global_variable); // Outputs:  my_global_variable

//2.  Use of a local variable:
  function my_local_func()
  {
    $my_local_variable = "My local string.";
    return vname($my_local_variable, get_defined_vars());
  }
  echo my_local_func(); // Outputs: my_local_variable

//3.  Use of an object property:
  class myclass
  {
    public function __constructor()
    {
      $this->my_object_property = "My object property  string.";
    }
  }
  $obj = new myclass;
  echo vname($obj->my_object_property, $obj); // Outputs: my_object_property
?>

您可以使用compact()来实现这一点。

$FooBar = "a string";

$newArray = compact('FooBar');

这将创建一个以变量名为键的关联数组。然后可以在需要的地方使用键名循环遍历数组。

foreach($newarray as $key => $value) {
    echo $key;
}