获取字符串中的变量名

Question

Hi I want to create a function in which I can pass a variable and output the name of the variable and its value as a sting. Something like this:

$firstname = 'John';
$lastname = 'Doe';

echo my_function($firstname); // outputs: "Var name: firstname , has: John"
echo my_function($lastname);  // outputs:  "Var name: lastname , has: Doe"

Answer 1

Take a look at get_defined_vars()

You can var_dump this and it will show all the variables you defined. You could then loop through and dump each ones value too.

http://php.net/get_defined_vars

Answer 2

The only easiest way i can think of this time is make use of $GLOBAL

<?php
function my_function($val) {
  foreach($GLOBALS as $name => $value) {
      if ($value == $val) {
          return "Var name: ".$name." , has: ".$val."<br>";
      }
  }
}

$first = 'John';
$firstname = 'John';
$lastname = 'Doe';
echo my_function($firstname); // outputs: "Var name: firstname , has: John"
echo my_function($lastname);

Output:

Var name: firstname_my , has: John
Var name: lastname_my , has: Doe

Let say if there is 2 variables with same

$first = 'John';
$firstname = 'John';

You can modify your code to differentiate like this

function my_function($val) {
   foreach($GLOBALS as $name => $value) {
       if ($value == $val && substr($name,-3) == "_my") {
          return "Var name: ".$name." , has: ".$val."<br>";
       }
   }
}

$first = 'John';
$firstname_my = 'John';
$lastname_my = 'Doe';

echo my_function($firstname_my); // outputs: "Var name: firstname , has: John"
echo my_function($lastname_my);