Create an array

Hopefully breaking each of these lines out makes it a little easier to read.

Line 14, reads characters into an array.  Check out the Hey, Scripting Guy! for a more detailed explanation of how ranges work.

Remember that our requirements were to remove the letters I and O, this is addressed in lines 15 & 16.

Line 17 also uses a range function.  Again, keeping in mind that we did not want to include the numbers 1 and 0, the range starts a number 2.

Finally, we combine both arrays into the new variable: $myAlphaNum