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
Notice: Undefined index: my_index C:\wamp\www\mypath\index.php on line 11
Warning: Undefined array key “my_index” in C:\wamp\www\mypath\index.php on line 11
Line 10 and 11 looks like this:
echo "My variable value is: " . $my_variable_name;
echo "My index value is: " . $my_array["my_index"];
What is the meaning of these error messages?
Why do they appear all of a sudden? I used to use this script for years and I’ve never had any problem.
How do I fix them?
This is a General Reference question for people to link to as duplicate, instead of having to explain the issue over and over again. I feel this is necessary because most real-world answers on this issue are very specific.
Related Meta discussion:
- What can be done about repetitive questions?
- Do “reference questions” make sense?