PHP and a weird error in my own function

Question

Here is the code:

function change_case($str, $type) {
 return str'.$type.'($str);
}
change_case('String', 'tolower');

It returns a parse error. What am I doing wrong?

• gen_Eric: What exactly are you trying to do? PHP variables need to start with $, and . is used for concatenation.

Answer 1

To use a variable function, you build the function name and put it in a variable first, then call it like so (use function_exists() in case someone passes an invalid type):

function change_case($str, $type) {
 $func = 'str' . $type;
 if (function_exists($func))
 return $func($str);
 else
 return $str;
}

No idea why you'd want to write such a function for strtolower() and strtoupper() though. Even if you wanted a custom function to cover both lower and upper, a variable function call is unnecessary.

• omtr: I use that function, because there is no support for cyrillic letters for ucfirst.

Answer 2

Why are you creating a function to call a single built-in PHP function? This seems completely backwards and will never, ever be worth the trouble. You can fix your problem by using the built-in PHP functions strtolower or strtoupper.

• Sampson: The practice of calling a native method from within a custom method is legitimate, especially if you plan on providing further customized results from the native functions. Remember, the OP asked how to do something, not whether the example was a good idea or not :)

Answer 3

What you want to do should be done like so:

function change_case($str, $type) {
 $function = 'str'.$type;
 if(function_exists($function)){
 return $function($str);
 }
}