php is null or empty?

php null
Erin Tucker picture Erin Tucker · Nov 23, 2011 · Viewed 425.6k times · Source

I have a question regarding NULL in PHP:

  $a = '';
  if($a == NULL) {
      echo 'is null';
  }

Why do I see is null when $a is an empty string? Is that a bug?

Answer

Godwin picture Godwin · Nov 23, 2011

What you're looking for is:

if($variable === NULL) {...}

Note the ===.
When use ==, as you did, PHP treats NULL, false, 0, the empty string, and empty arrays as equal.

Related questions

PHP json_decode() returns NULL with valid JSON?

I have this JSON object stored on a plain text file: { "MySQL": { "Server": "(server)", "Username": "(user)", "Password": "(pwd)", "DatabaseName": "(dbname)" }, "Ftp": { "Server": "(server)", "Username": "(user)", "Password": "(pwd)", "RootFolder": "(rf)" }, "BasePath": "../../bin/", "NotesAppPath": "notas", "SearchAppPath": "buscar", "BaseUrl": "http:\/\/montemaiztusitio.com.ar", "…

Read More
MySQL and PHP - insert NULL rather than empty string

I have a MySQL statement that inserts some variables into the database. I recently added 2 fields which are optional ($intLat, $intLng). Right now, if these values are not entered I pass along an empty string as a value. How do …

Read More
What is the PHP syntax to check "is not null" or an empty string?

Possible Duplicate: Check if a variable is empty Simple PHP question: I have this stement: if (isset($_POST["password"]) && ($_POST["password"]=="$password")) { ...//IF PASSWORD IS CORRECT STUFF WILL HAPPEN HERE } Somewhere above this statement I use the following …

Read More