documentation for 'open': some clarification?
I'm been doing more and more of file text parsing inside R instead of
coping with Perl. For that, I need open a file and read it line-by-line.
I found the documentation for 'open' isn't very clear.
Right now it has
,----[ *help(R)[open]* ]
| 'open' opens a connection. In general functions using connections
| will open them if they are not open, but then close them again, so
| to leave a connection open call 'open' explicitly.
`----
It seems that one has to call 'open' to open a live connection that can be
parsed line by line (using readLines() or scan() to read). But open()
cannot be directly applied to a file name.
In fact, one only needs supply the 'open' argument in file() with
something other than the empty string,
,----
| > con <- file ("S200.dat")
| > isOpen (con)
| [1] FALSE
| > con <- file ("S200.dat", open = "r")
| > isOpen (con)
| [1] TRUE
`----
It is not clear to me how 'open()' is supposed to be used. It took me a
while to figure this out and I thought it might be worthwhile to add one
sentence or two to make it more clear in the doc.
Cheers,
Michael
Na (Michael) Li, Ph.D. Division of Biostatistics A443 Mayo Building, MMC 303 School of Public Health 420 Delaware St SE University of Minnesota Minneapolis, MN 55455 Phone: (612) 626-4765 Email: nali@umn.edu Fax: (612) 626-0660 http://www.biostat.umn.edu/~nali GPG Public Key: http://www.umn.edu/lookup?SET_INSTITUTION=UMNTC&UID=nali&show_pgp=1