Obtaining substrings with variable number of characters

Question

I have a set of file names that contain within the name an ID number.  These ID numbers do not necessarily have the same character length.  Any ideas on how to achieve this?  This is what I have for fixed ID character length.

For (k =1,
       k < N Items( listOfFiles ),
       k++,
       IDNumber = subsr( listOfFiles, 1, 8 );
       insertinto( listOfIDNumbers, IDNumber );
);

Issue arises when ID number is not 7 characters in length and I have complex filenames.
ABCDE_1234567_ABCD.csv
ABC_123_ABCDEFG.csv

What I want is to just get 1234567 and 123.  Can I key off .csv somehow or perhaps underscore?

mpb · Answer

Good point about regular expressions. For the record, in the case you described, the following would also work:

IDNumber = Word( 1, listOfFiles, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" )

unknown · Answer

The other option would be to leverage regular expressions.  If the file names did not have _'s separating the various portions but the ID name was uniquely composed of numbers and the rest of the file name did not contain numbers then this would work.

A regex syntax guide that I always reference is:
http://www.regular-expressions.info/reference.html

Fixed a stupid grammar mistake

Message was edited by: mewing

bhagbom · Answer

That works great, thanks for the help!