[R] Read to the end of a stream (package Rstreams)

[Peter Dalgaard BSA]

Sven Garbade <garbade at psy.uni-muenchen.de> writes:

> Hi there,
> 
> I want to read all data from a binary file (with package Rstreams). I
> tried the following function (small piece of code):
> 
> readdata <- function (file) {
>     # open file
>     s <- openstream(file, "read")
> 	
>     # read int values 
>     while (s$position <= s$size) {
>     readint(s, 1, 2) -> type
>     [...]
>     }
> 
>  return()
> }
> 
> and got the following error:
> 
> > Error in while (s$position <= s$size) { : missing value where logical needed
> 
> Is it possible to read data from the start to the finish of a stream?

Yes, but not like that. s does not have the position and size
components; only summary(s) has those. So

while (summary(s)$position < summary(s)$size) {...}

would do it (note: at "==", you're at the end). However, it would be
more natural to use the fact that readint returns numeric(0) on EOF:

while ( length(type <- readint(s, 1, 2)) )
{
	...
}

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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