Using the Windows Clipboard, or Passing Data Quickly From Excel to R and Back Again

June 19, 2013
By

(This article was first published on TeachR, and kindly contributed to R-bloggers)

Two of my favorite functions are copy.table() and paste.table(). I’m going to turn this story on its head and give you the ending first.

# Copy data out of R
copy.table <- function(obj, size = 4096) {
  clip <- paste('clipboard-', size, sep = '')
  f <- file(description = clip, open = 'w')
  write.table(obj, f, row.names = FALSE, sep = '\t')
  close(f)  
}

# Paste data into R
paste.table <- function() {
  f <- file(description = 'clipboard', open = 'r')
  df <- read.table(f, sep = '\t', header = TRUE)
  close(f)
  return(df)
}

The first allows you to copy a data frame to the clipboard in a format that Excel knows how to deal with. All you have to do after running copy.table() is select the cell in Excel (or position in a text file) you want to paste to and press CNTL+V. It works on anything that can be coerced to a data frame, too, so vectors, table objects, etc. are all valid objects for copying.

# These all work
copy.table(1:100)
copy.table(letters)
copy.table(my.df)
copy.table(table(my.df$col1))
copy.table(matrix(1:20, nrow = 2))

If you get an error when trying to copy it is most likely because obj requires more than 4096 bytes to be represented as text. You can pass a larger number as the second argument to make it work. I’ve tried experimenting with estimating an upper bound on the size of an object but it hasn’t worked out yet. For now, if I can’t get something to copy I just double the second argument.

# If my.df is of moderate size
copy.table(my.df)

# If my.df is huge
copy.table(my.df, 10000)

Pasting works in a similar way. Select the range in Excel you want to copy (including the header) and press CNTL+C. Then run

other.df <- paste.table()

This one doesn’t take any arguments because it goes straight to the clipboard and pulls everything there.

I use both of these quite a bit when doing quick and dirty work where I need to have a more tactile, hands-on, “under the influence of Excel” workflow. They are interactive, so I don’t use them in the final production level code for any reproducible studies. But, for development and for quick stuff they are really helpful.

Have fun! Please forward on to someone else you know who uses R. Thanks!


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