[R] Faster Printing Alternatives to 'cat'

[Henrik Bengtsson]

Hint: You already know how to write all rows at once and row by row -
now write a set of rows each time. /H

On Sat, Jan 17, 2009 at 7:21 AM, Gundala Viswanath <gundalav at gmail.com> wrote:
> How do you do that Henrik? Write.table doesn't have that option.
>
> Usage:
>     write.table(x, file = "", append = FALSE, quote = TRUE, sep = " ",
>                 eol = "\n", na = "NA", dec = ".", row.names = TRUE,
>                 col.names = TRUE, qmethod = c("escape", "double"))
>
>
> - Gundala Viswanath
> Jakarta - Indonesia
>
>
>
> On Sun, Jan 18, 2009 at 12:09 AM, Henrik Bengtsson <hb at stat.berkeley.edu> wrote:
>> Do it in chunks of rows. /H
>>
>> On Sat, Jan 17, 2009 at 6:55 AM, Gundala Viswanath <gundalav at gmail.com> wrote:
>>> Hi Hadley,
>>>
>>> I had to do it by line. Because, in practice, I will
>>> manipulate the figures and string before printing it.
>>>
>>> And I can't bind these results into one new object,
>>> because there are literally millions of this lines, and
>>> R object can't handle that in my 4GB Ram memory.
>>>
>>> I tried your suggestion already, I have memory problem
>>>
>>>> x <- cbind(dat$V1, as.character(dat$V2))
>>> Error: cannot allocate vector of size 4.2 Gb
>>> Execution halted
>>>
>>> - Gundala Viswanath
>>> Jakarta - Indonesia
>>>
>>>
>>>
>>> On Sat, Jan 17, 2009 at 11:39 PM, hadley wickham <h.wickham at gmail.com> wrote:
>>>> On Sat, Jan 17, 2009 at 7:59 AM, gundalav <gundalav at gmail.com> wrote:
>>>>> Dear Jim and all,
>>>>>
>>>>> Allow me to ask your expert opinion.
>>>>>
>>>>>
>>>>> Using the data (16Mb) downloadable from here:
>>>>>
>>>>> http://drop.io/gundalav/asset/test-data-zip
>>>>>
>>>>>
>>>>> It took this long under 1994.070Mhz Cpu Linux, using
>>>>> "write.table"
>>>>>
>>>>>> proc.time() - ptm1
>>>>>     user    system   elapsed
>>>>> 16581.833  5787.228 21386.064
>>>>>
>>>>>
>>>>>
>>>>> __MYCODE__
>>>>>
>>>>> args <- commandArgs(trailingOnly=FALSE)
>>>>> fname <- args[3]
>>>>> dat <- read.delim(fname, header=FALSE);
>>>>>
>>>>> output <- file('output_writetable.txt', 'w')
>>>>>
>>>>>
>>>>> ptm1 <- proc.time()
>>>>> for (i in 1:nrow(dat)) {
>>>>>
>>>>>     #cat(dat$V1[i]," ", as.character(dat$V2[i]),"\n", sep="")
>>>>>     write.table(cbind(dat$V1[i], as.character(dat$V2[i])),
>>>>> file=output, sep="\t", quote=FALSE, col.names=FALSE, row.names=FALSE)
>>>>> }
>>>>>
>>>>> close(output)
>>>>> proc.time() - ptm1
>>>>> __END__
>>>>>
>>>>> Perhaps I misunderstood you. But seems that this is
>>>>> truly slow. Is there a way I can speed it up?
>>>>
>>>> Don't do it line by line!
>>>>
>>>> write.table(dat[, c("V1", "V2")], file='output_writetable.txt',
>>>> sep="\t", quote=FALSE, col.names=FALSE, row.names=FALSE)
>>>>
>>>> Hadley
>>>>
>>>> --
>>>> http://had.co.nz/
>>>>
>>>
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>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>
>