Save R source codes in a loop

Question

I would like to write several R source codes in a loop. However I am not getting a functional source file. That´s what I tried:

for(k in 1:10){
    cod <- 'x <- 1+k
         nam <- paste0(x, ".txt")
         write.table(x, nam)'
    cod <- gsub("x", k, cod)
    file <- paste0("source", k, ".R")
    dput(cod, file=file)}

Strictly speaking, I would like to get exactly the code in the cod object in 10 sources codes (differing by the k, which go from 1 to 10). Actually this code produce all the 10 files, but they contain strange characters and are no functional at all.

dput writes an ASCII text representation of an R object, it's not mean for saving output. Use writeLines, sink, cat — romants
– romants, Commented Jan 19, 2016 at 18:12
Are you sure you actually want to do this? It seems very strange. What are you doing with these R files once you've made them? Also, your first line ends up as things like 5 <- 1+k because you substitute x with the value of k. What is going on? — Spacedman
– Spacedman, Commented Jan 19, 2016 at 18:14
@Spacedman, probably there is a much faster way to do what I want. Nevertheless, using several source codes is possible to run much faster than a canonical loop. — user2120870
– user2120870, Commented Jan 19, 2016 at 19:02
Why is it faster? Because you can run them in parallel? Sure, but don't duplicate the code. Put the code in one file as a function can call that from 10 scripts that just have source("code.R"); dothing(1) and dothing(2) and so on. Or better still parameterise the script and use littler. — Spacedman
– Spacedman, Commented Jan 19, 2016 at 19:06

Gopala · Accepted Answer · 2016-01-19 18:15:14Z

1

Try to modify to writeLines from put, also change your formatting of string as follow:

for(k in 1:10) {
  cod <- 'x <- 1+k\nnam <- paste0(x, ".txt")\nwrite.table(x, nam)'
  cod <- gsub("x", k, cod)
  file <- paste0("source", k, ".R");
  writeLines(cod, file)
}

answered Jan 19, 2016 at 18:15

Gopala

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3 Comments

user2120870 Over a year ago

It worked well! However, in my real code I have some characters which seems to be missed in the final source.R files. For example, I used write.table(x, nam, sep="\t"), which is modified wrongly to write.table(x, nam, sep=" "). Do you have any idea to deal with that?

Gopala Over a year ago

Sometimes, \t will look like a space given the width of other data columns, but yet may be a tab. Also, make sure to use row.names = FALSE, quote = FALSE options to write.table.

user2120870 Over a year ago

I also got a problem in another section with the ` character: list.files(pattern = "\\.txt$")` was been turned into list.files(pattern = "\.txt$") given the follow error when I tried to execute the source: Error: '\.' is an unrecognized escape in character string starting ""\." Execution halted

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