library("R.utils") # A data frame set.seed(42) n <- 5L data <- data.frame( index = 1:n, symbol = letters[1:n], x = runif(n), y = rnorm(n), stringsAsFactors=FALSE ) # Write to tab-delimited file (using a connection) pathname <- tempfile(fileext=".tsv") con <- file(pathname, open="w") writeDataFrame(data, file=con, createdBy="R.utils") close(con) # Append another set of rows writeDataFrame(data, file=pathname, append=TRUE) # There should only be one header and one set of column names print(readLines(pathname)) # Overwrite using a connection con <- file(pathname, open="w") writeDataFrame(data, file=con, overwrite=TRUE) close(con) # Overwrite using a filename writeDataFrame(data, file=pathname, overwrite=TRUE)