If or isset?

[subnet_rx]

Is there an advantage to using isset() over if() if your wanting to know if a variable has a value?

[wildteen88]

Is there an advantage to using isset() over if() if your wanting to know if a variable has a value?

isset does not check variables values. isset only checks whether a variable exists or not.

[roopurt18]

AFAIK isset() is a function while if is a language construct, which means you can use isset() in places where you can't use if.

[subnet_rx]

So basically, I'm running code if a variable has a value.

 

if($v)...

 

Is that the best way or should I be doing this:

 

if(isset($v))

[roopurt18]

It depends on the context.

 

  function someFunc($arg){
    if($arg){ // Test that the value exists
    }
  }

The example above doesn't make any sense.  The argument $arg isn't optional so it has to exist.

 

  if($value){ // Ensure a value is true
  }

This will work as expected, the if body will only execute if the variable is true.  However, if the variable is not set PHP will raise an error, possibly silently.

 

Use isset() when there is a possibility the variable is not set and then test it's value.

  if(isset($var) && $var){
    // If the var exists and evaluates true
  }

[wildteen88]

I'd use the third method:

  if(isset($var) && $var){
    // If the var exists and evaluates true
  }

For use with variables set from the client, eg _GET, _POST and _COOKIE.