Question

Does empty() function validate all of this cases:

1.var=null

2.var=empty string “”/” ”

3.var=not set

Example for validate use (Should I add some more code for validation or empty() enough?):

if(!empty($userName)){
  //some code
}

else{
  echo "not valid user name"
}

---

Edit: should isset() used before empty() or empty() includes the isset() case?

Answer 1

Given the following i would say it fits your needs:

The following things are considered
to be empty:

* "" (an empty string)
* 0 (0 as an integer)
* "0" (0 as a string)
* NULL
* FALSE
* array() (an empty array)
* var $var; (a variable declared, but without a value in a class)

EDIT:

should isset() used before empty() or
empty() include isset() case?

This depends on the usage. IF you are in a position where you cant be sure $username exists then you need to use isset first to avoid an error about a nonexistent variable. If on the other hand you are sure $username will always exist then you can jsut test for the empty value and leave it at that.