Picaxe Basic Issues

In Picaxe Basic how do I write a piece of code that I only want to execute the first time my main loop runs. For example: I want to get and store an initial value for a sensor and use that later on in my code; however, once I have stored this initial value I don't want the program storing a new value the next time it runs.

Can’t you just do that

Can’t you just do that above the main loop?

Seems to work, thank you!

Seems to work, thank you!