“Notice: Undefined variable”, “Notice: Undefined index”, and “Notice: Undefined offset” using PHP

Question

I\'m running a PHP script and continue to receive errors like:

Notice: Undefined variable: my_variable_name in C:\\wamp\\www\\mypath\\index.php on line 10

Answer 1

undefined index means in an array you requested for unavailable array index for example

undefined variable means you have used completely not existing variable or which is not defined or initialized by that name for example

undefined offset means in array you have asked for non existing key. And the solution for this is to check before use

php> echo array_key_exists(1, $myarray);