R help - Mar 2005 - Writing to a file

Here is a simple question. Is there a quicker way to write to a file 
several rows of data at a time rather than one line at a time? How can 
the code below be optimized to write several rows at a time to a file 
rather than one line at a time. See my slow method of write.table below:

---------------------------
x<-1000
for( i in 1:385420)
    (
    if(Info[i,4] > x)
       write.table (cbind(Info[i,1], Info[i,4], file="/tmp/CT.dat", 
append=TRUE, row.names=FALSE, col.names=FALSE)

Thanks,

-Melanie

Would the following do?

x <- 1000
write.table(Info[Info[,4] > x, c(1, 4)], file="/tmp/CT.dat")

Andy
> From: Melanie Vida
> 
> Here is a simple question. Is there a quicker way to write to a file 
> several rows of data at a time rather than one line at a 
> time? How can 
> the code below be optimized to write several rows at a time to a file 
> rather than one line at a time. See my slow method of 
> write.table below:
> 
> ---------------------------
> x<-1000
> for( i in 1:385420)
>     (
>     if(Info[i,4] > x)
>        write.table (cbind(Info[i,1], Info[i,4],
file="/tmp/CT.dat",
> append=TRUE, row.names=FALSE, col.names=FALSE)
> 
> Thanks,
> 
> -Melanie
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 
> 
>

Yes, Andy, the command you gave takes only a minute to output the whole 
data set to a file rather than mine, which takes hours to complete the 
file ouput operation. Thanks!

Liaw, Andy wrote:
>Would the following do?
>
>x <- 1000
>write.table(Info[Info[,4] > x, c(1, 4)], file="/tmp/CT.dat")
>
>Andy
>
>  
>
>>From: Melanie Vida
>>
>>Here is a simple question. Is there a quicker way to write to a file 
>>several rows of data at a time rather than one line at a 
>>time? How can 
>>the code below be optimized to write several rows at a time to a file 
>>rather than one line at a time. See my slow method of 
>>write.table below:
>>
>>---------------------------
>>x<-1000
>>for( i in 1:385420)
>>    (
>>    if(Info[i,4] > x)
>>       write.table (cbind(Info[i,1], Info[i,4],
file="/tmp/CT.dat",
>>append=TRUE, row.names=FALSE, col.names=FALSE)
>>
>>Thanks,
>>
>>-Melanie
>>
>>______________________________________________
>>R-help at stat.math.ethz.ch mailing list
>>https://stat.ethz.ch/mailman/listinfo/r-help
>>PLEASE do read the posting guide! 
>>http://www.R-project.org/posting-guide.html
>>
>>
>>
>>    
>>
>
>
>
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