Question

How to get a variable name as a string in PHP

Answer 1

function get_variable_name($var) {
    foreach($GLOBALS as $variable_name => $value) {
        if ($value === $var) {
            return $variable_name;
        }
    }
 
    return false;
}
 
$num = 23452;
echo get_variable_name($num) . "\n";
 
$str = "PHP";
echo get_variable_name($str) . "\n";
 
$arr = array(1, 2, 3);
echo get_variable_name($arr) . "\n";
 
   
  
/*
run:
  
num
str
arr
  
*/

 

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Answer 2

function get_variable_name($var) {
    $trace = debug_backtrace();
    $this_file_source_code = file( __FILE__ );
    $the_line_code_that_call_to_this_function = $this_file_source_code[$trace[0]['line'] - 1];

    // get function argument - the $var name
    preg_match( "#\\$(\w+)#", $the_line_code_that_call_to_this_function, $match); 
      
    return $match;
}
  
$num = 23452;
print_r(get_variable_name($num));
  
$str = "PHP";
print_r(get_variable_name($str));
  
$arr = array(1, 2, 3);
print_r(get_variable_name($arr));
  
    
   
/*
run:
  
Array
(
    [0] => $num
    [1] => num
)
Array
(
    [0] => $str
    [1] => str
)
Array
(
    [0] => $arr
    [1] => arr
)
   
*/

 

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Answer 3

function get_variable_name($var) {
    $trace = debug_backtrace();
    $this_file_source_code = file($trace[0]['file']);
    $the_line_code_that_call_to_this_function  = $this_file_source_code[$trace[0]['line'] - 1];
    $pattern = '#(.*)'.__FUNCTION__.' *?\( *?(.*) *?\)(.*)#i';
    
    // get function parameter - the $var name
    $var  = preg_replace($pattern, '$2', $the_line_code_that_call_to_this_function);

    return trim($var);
}
 
$num = 23452;
echo get_variable_name($num) . "\n";
 
$str = "PHP";
echo get_variable_name($str) . "\n";
 
$arr = array(1, 2, 3);
echo get_variable_name($arr) . "\n";
 
   
  
/*
run:
 
$num
$str
$arr

*/

 

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