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

manpreet Best Answer 2 years ago

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

Line 10 and 11 looks like this:

echo "My variable com/tag/value">value is: " . $my_variable_name;
echo "My index com/tag/value">value is: " . $my_array["my_index"];

What is the meaning of these error messages?

Why do they appear all of a sudden? I com/tag/use">used to com/tag/use">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?

manpreet 2 years ago

Its because the variable '$user_location' is not getting defined. If you are using any if loop inside which you are declaring the '$user_location' variable then you must also have an else loop and define the same. For example:

$a=10;
if($a==5) { $user_location='Paris';} else { }
echo $user_location;

The above code will create error as The if loop is not satisfied and in the else loop '$user_location' was not defined. Still PHP was asked to echo out the variable. So to modify the code you must do the following:

$a=10;
if($a==5) { $user_location='Paris';} else { $user_location='SOMETHING OR BLANK'; }
echo $user_location;