[R] how to handle no lines in input with pipe()

From: Andrew Yee <yee_at_post.harvard.edu>
Date: Mon, 04 Apr 2011 17:30:36 -0400


This has to do with using pipe() and grep and read.csv()

I have a .csv file that I grep using pipe() and read.csv() as follows:

read.csv(pipe('grep foo bar.csv'))

However, is there a way to have this command run when for example, there is no "foo" text in the bar.csv file? I get an error message (appropriately):

Error in read.table(file = file, header = header, sep = sep, quote = quote, :   no lines available in input

Is there a way to "inspect" the output of pipe before passing it on to read.csv()?

Thanks,
Andrew



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