[R] Reading in large file in pieces

From: Sean Davis <sdavis2_at_mail.nih.gov>
Date: Fri 23 Dec 2005 - 10:08:51 EST


I have a large file (millions of lines) and would like to read it in pieces. The file is logically separated into little modules, but these modules do not have a common size, so I have to scan the file to know where they are. They are independent, so I don't have to read one at the end to interpret one at the beginning. Is there a way to read one line at a time and parse it on the fly and do so quickly, or do I need to read say 100k lines at a time and then work with those? Only a small piece of each module will remain in memory after parsing is completed on each module.

My direct question is: Is there a fast way to parse one line at a time looking for breaks between "modules", or am I better off taking large but manageable chunks from the file and parsing that chunk all at once?

Thanks,
Sean



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