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PHP: Changing a Variable

The word "variable" itself indicates that it can be changed. Indeed, the value of a variable can change throughout your code.


// greeting 
$greeting = 'Father!';

$greeting = 'Mother!';

The name remains unchanged, although it stores new data. Note that variables in PHP don't need to be declared. Instead, a variable is declared the first time it's used in a program.

Variables are a powerful yet dangerous thing. You can never be sure exactly what's written inside it without analyzing the code that comes before the variable. This is what developers do during debugging, when they try to figure out why the program doesn't work, or doesn't work as intended.

As you'll see later, PHP has more than just variables. Moreover, variables are not often used with the goal of changing them in mind. They're more often used as a storage method.


In this exercise, a variable has been defined with a string inside it. Override the value of this variable and assign it a string in which the characters of the original string are arranged in reverse order.

The exercise doesn't pass checking. What to do? 😶

If you've reached a deadlock it's time to ask your question in the «Discussions». How ask a question correctly:

  • Be sure to attach the test output, without it it's almost impossible to figure out what went wrong, even if you show your code. It's complicated for developers to execute code in their heads, but having a mistake before their eyes most probably will be helpful.
In my environment the code works, but not here 🤨

Tests are designed so that they test the solution in different ways and against different data. Often the solution works with one kind of input data but doesn't work with others. Check the «Tests» tab to figure this out, you can find hints at the error output.

My code is different from the teacher's one 🤔

It's fine. 🙆 One task in programming can be solved in many different ways. If your code passed all tests, it complies with the task conditions.

In some rare cases, the solution may be adjusted to the tests, but this can be seen immediately.

I've read the lessons but nothing is clear 🙄

It's hard to make educational materials that will suit everyone. We do our best but there is always something to improve. If you see a material that is not clear to you, describe the problem in “Discussions”. It will be great if you'll write unclear points in the question form. Usually, we need a few days for corrections.

By the way, you can participate in courses improvement. There is a link below to the lessons course code which you can edit right in your browser.


  • Type your code between the // BEGIN and // END lines in the editor.


  • A variable is a way to store information and name it for later use in code.

If you got stuck and don't know what to do, you can ask a question in our community