Java for return phone keypads

Question

I get a problem about returning phone keypads. For instance, if I input 1-80-0Apple, it will return 1-80-027753. Could somebody tell me how to figure out this one?

Answer 1

If you are going to deal with different formats for phone numbers entered by users I would suggest that you use Google's libphonenumber (http://code.google.com/p/libphonenumber/). It has lots of utilities for handling phone numbers.

For the case that you ask, you can do this:

String phoneNumber = PhoneNumberUtil.convertAlphaCharactersInNumber("1-80-0Apple");
System.out.println(phoneNumber);

That would print:

1-80-027753

Answer 2

Maintain a lookup table between letters and numbers:

A -> 2
B -> 2
C -> 2
D -> 3
etc

Then loop through each letter in the number and replace it with the corresponding number.