Extracting a part of a string

[hersala]

Dear users,

Please, how can I extract a part (date) of a string like this:

EAA-F54-20091023.bin

Or if exist an analogous to this command taken from GrADS software?

subwrd (string, n)  # Gets a single word from a string. The result is the nth word of string.

Thank you very much.

Hernán