how to check what is the name of the variable that is passed to a function ?

madrazel

examle:

$the_variable_i_want_to_know_name_of = 
    array('dontwantthis'=>'somestring','the_variable_i_want_to_know_name_of'=>'someotherstring');

function my_func($str) {

return //do the magic here...

}

$result = my_func($the_variable_i_want_to_know_name_of);

//and the result should be string - "someotherstring"

It seems silly to check the name I already know about, but I need the name inside function to check if it is array and if that array have a key that is identical to the name of the array, to get data from it

NogDog

Well, if I were doing it, I'd simply pass the key of interest as another function arg:

function myfunc($arr, $key)
{
   if(isset($arr[$key]))
   {
      return $arr[$key];
   }
   return false;
}

myfunc($the_variable_i_want_to_know_name_of, 'the_variable_i_want_to_know_name_of');

But if you don't want or can't do that for some reason, I suppose you could do something ugly like:

myfunc($str)
{
   global $$str;
   if(isset($$str[$str]))
   {
       return $$str[$str];
   }
   return false;
}

myfunc('the_variable_i_want_to_know_name_of');

halojoy

It is not possible to know the variable name of the value sent to function.
And it does not make good sense.
If I send a string like this

$result = my_func('god day');

it does not even exist a variable name.

The values of all arguments sent to a function we can get:

<?php

function my_func() {

// all arguments in array $a
$a = func_get_args();

return $a;  //do the magic here...

}

$arg1 = array('something'=>'value1', 'next'=>'value2');
$arg2 = 'good day';

$result = my_func($arg1, $arg2);
echo '<pre>';
var_export($result);

?>

niroshan

Hi madrazel,

Since you know the name of the array variable you can simple take use of is_array() and array_key_exists() functions.

function my_func($str) {

if(is_array($str) && array_key_exists('the_variable_i_want_to_know_name_of', $str))
{
            return //do the magic here...		
}
}

Thanks,
best Regards,
Niroshan

Weedpacket

Whenever this question comes up it seems to involve a confusion about the difference between variables and values. Values get passed to functions; variables are just names used in source code to refer to values. I know there's often talk about passing variables - I'm no doubt guilty of it myself often enough - but it is sloppy and I am trying to kick the habit.

The same value could have multiple names (in PHP they're called "references") and the function isn't going to know which one happened to have been used at the spot in the source code where the function call was written (not to mention what happens when bytecode compilers and optimisers get to do their thing).