Dirk, thanks. On Thu, Oct 14, 2010 at 9:42 AM, Dirk Eddelbuettel <[email protected]> wrote: > > On 14 October 2010 at 11:21, Dirk Eddelbuettel wrote: > | On 14 October 2010 at 08:49, Saptarshi Guha wrote: > | | Hello, > | | I have this script which will be invoked as > | | > | | Rscript a.r < a.r > | | > | | a.r follows > | | > | | #!/usr/bin/Rscript --vanilla > | | f=file("stdin") > | | while(TRUE){ > | | y=readLines(f,n=1,warn=TRUE) > | | if(length(y)==0) break else print(y) > | | } > | | > | | > | | But it only reads one line from a.r > | | How can I read line by line from standard input? > | > | If you can substitute in r (from littler) for Rscript, then you get proper > | behaviour. Here is an old example from littler: > | > | $ ls -l /usr/bin | awk '!/^total/ {print $5}' | \ > | r -e 'fsizes <- as.integer(readLines()); print(summary(fsizes))' | \ > | tail -2 > | Min. 1st Qu. Median Mean 3rd Qu. Max. > | 1 1720 10900 108000 39200 11100000 > | $ > | > | This uses awk to get the file size from ls, and then runs R's summary() over > | it. For some reason, readLines() now echos back to the screen which is why > I > | added the 'tail -2' at the end. > > Got it. We changed something since we first created this example in 2006, and > we now need to set the -i flags. So with that: > > $ ls -l /usr/bin | awk '!/^total/ {print $5}' | \ > r -i -e 'fsizes <- as.integer(readLines()); print(summary(fsizes))' > Min. 1st Qu. Median Mean 3rd Qu. Max. > 1 1720 10900 108000 39200 11100000 > $ > > Dirk > > > -- > Dirk Eddelbuettel | [email protected] | http://dirk.eddelbuettel.com >
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