R copy text from function output with for loop to clipboard - r

Question

I've written a little function that helps renaming columns by looping through each variable and pasting various punctuation around it so that text is sent to the console. This can then be copied into my script and rename variables as required. This is the function:
library(tidyverse)
tidy_rename <- function (df) {
df_name <- deparse(substitute(df))
names(df) <- tolower(names(df))
cat(paste(df_name, " <- ", paste(df_name, "%>%\n\t rename(")))
for (i in names(df)) {
cat(paste("\t\t", paste(paste("=", paste(paste('"', i), '"'))), ","), sep="\n")
}
writeLines(")"
)
}
If I use this on a dataset:
test_df <- data.frame("VarIable 1" = c(1), "sizrd" = c(1), "dat 1" = c(1),
"x-cord" = c(1), "y-crf" = c(1), "aGe" = c(1), check.names=F)
tidy_rename(test_df)
which gives the following which can be copied and pasted into script:
test_df <- test_df %>%
rename( = " variable 1 " ,
= " sizrd " ,
= " dat 1 " ,
= " x-cord " ,
= " y-crf " ,
= " age " ,
)
What I would like is to automatically copy this output to the clipboard within the function. I'm not sure how to use writeClipboard around the forloop. This doesn't work:
tidy_rename <- function (df) {
df_name <- deparse(substitute(df))
names(df) <- tolower(names(df))
writeClipboard(
cat(paste(df_name, " <- ", paste(df_name, "%>%\n\t rename(")))
for (i in names(df)) {
cat(paste("\t\t", paste(paste("=", paste(paste('"', i), '"'))), ","), sep="\n")
}
writeLines(")"
)
)
}
Any suggestions please?

Answer 1

Expanding on my comment to eliminate any confusion.
A method or suggestion is to store the string in a variable, which can then be output in the end. Note from the value of cat(...) is NULL (it doesnt return the string). This requires 2 variables, lets call them str and newstr. I'll let str store the entire string that you want to copy, and newstr store the current string that is output by cat(...).
tidy_rename <- function (df) {
df_name <- deparse(substitute(df))
names(df) <- tolower(names(df))
str <- paste(df_name, " <- ", paste(df_name, "%>%\n\t rename("))
cat(str)
for (i in names(df)) {
#Store variable at each iteration and expand str. Output newstr.
newstr <- paste("\t\t", paste(paste("=", paste(paste('"', i), '"'))), ",")
str <- paste(str, newstr, sep = "\n")
cat(newstr, sep="\n")
}
newstr <- ")"
str <- paste0(str, newstr)
cat(newstr)
writeClipboard(str)
}
Note how the output is stored in str at each iteration but newstr is output.
As a side note i suggest that OP checks out the collapse argument of paste (alternatively paste0). I don't have the full overview, but it seems like this could eliminate 2 - 3 calls to paste if the strings were collapsed within one of the function calls.