Get a question about using INPUT PROGRAM to create a subset of one file in which the ID of the rows appears only in another file. Yes, I know proc MATCH FILE and TABLES subcommand can do it, but deal to some restrictions, I need to do it via INPUT PROGRAM ... DATA LIST .... Any hints are appreciated. Thanks in advance.

Here is my question: --------------------

I have 2 text files, one is a list of ID that I will use in the analysis, another is a transaction file for my entire database. Both files are sorted by ID already. The text files look like the followings (original files extremely big, the followings are just to illustrate the idea):

ID_list.txt -------------- ID 001 002 005

Transaction.txt --------------------- ID DollAmt 001 14 001 20 001 15 002 20 002 15 003 40 004 10 005 17 005 17 006 18

What I want to create using INPUT PROGRAM and END INPUT: ---------------------------------------------------------------------------------------------

ID DollAmt 001 14 001 20 001 15 002 20 002 15 005 17 005 17

What I want to do is to create a subset of the Transaction.txt which contains the rows with the IDs appears only in the ID_list.txt. However I would like to do it such that none of the files needed to be read and saved as SPSS format data files first (because of memory and space issues). That is, I would like to use INPUT PROGRAM and END INPUT PROGRAM etc to do the task instead of the MATCH FILES … TABLE … procedure. Could you please shed me some light? Many Thanks in advance.