How to get a variable name as a string in PHP?
Use variable name as a string to get the variable name. There are many ways to solve this problem some of them are discussed below:
Table of Content
Method 1: Using $GLOBALS:
It is used to reference all variables available in the global scope. It is an associative array containing the reference of all variables currently defined in the global scope.
Example: This example uses $GLOBAL reference to get the variable name as a string.
<?php
// Declare and initialize a variable
$test = "This is a string";
// Function that returns the variable name
function getVariavleName($var) {
foreach($GLOBALS as $varName => $value) {
if ($value === $var) {
return $varName;
}
}
return;
}
// Function call and display the
// variable name
print getVariavleName($test);
?>
Output
test
Method 2: Using $$ Operator
The $$var_name is known as reference variable where $var_name is a normal variable. The $$var_name used to refer to the variable with the name as value of the variable $var_name.
Example:This example uses $$ operator to get the variable name as a string.
<?php
// Declare and initialize a variable
$name = "test";
// Reference variable to store string
$$name = "This is a string";
// Display result
print($name);
?>
Output
test
Using debug_backtrace()
Using debug_backtrace() in PHP, you can extract a variable name from the debug information. This involves reading the specific line of code where the function was called.
Example
<?php
function getVariableName()
{
$trace = debug_backtrace();
$line = file($trace[0]["file"])[$trace[0]["line"] - 1];
preg_match('/\\$(\w+)/', $line, $matches);
return $matches[1];
}
$myVar = "Hello, World!";
$varName = getVariableName();
echo $varName . PHP_EOL; // Output: myVar
?>
Output
varName
Using get_defined_vars() and array_search()
The get_defined_vars() function returns an array of all defined variables, both local and global. By searching this array, we can find the key (variable name) corresponding to a given value.
Example:
<?php
// Function to get the variable name as a string
function getVariableName(&$var) {
// Get all defined variables in the current scope
$definedVars = get_defined_vars();
// Search for the variable in the defined variables array
$variableName = array_search($var, $definedVars, true);
// Return the variable name if found, otherwise return null
return $variableName !== false ? $variableName : null;
}
// Example variables
$exampleVar = "test value";
$anotherVar = 42;
// Get the variable names
$exampleVarName = getVariableName($exampleVar);
$anotherVarName = getVariableName($anotherVar);
echo "The variable name of exampleVar is: " . $exampleVarName . "\n";
echo "The variable name of anotherVar is: " . $anotherVarName . "\n";
?>
Output
The variable name of exampleVar is: var The variable name of anotherVar is: var
