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Reimplemented fgetl

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This commit is contained in:
Waldir Leoncio 2020-07-31 09:26:57 +02:00
parent f036a33bca
commit 372500d750
3 changed files with 52 additions and 12 deletions
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18
R/fgetl.R
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@ -1,26 +1,19 @@
#' @title Read line from file, removing newline characters
#' @description Equivalent function to its homonymous Matlab equivalent.
#' @param file file to be read
#' @param file character vector to be read, usually an output of `fopen()`
#' @return If the file is nonempty, then fgetl returns tline as a character vector. If the file is empty and contains only the end-of-file marker, then fgetl returns tline as a numeric value -1.
#' @author Waldir Leoncio
#' @seealso fopen
#' @export
fgetl <- function(file) {
# ==========================================================================
# Validation
# ==========================================================================
if (file == "") return(-1)
if (length(file) <= 1) return(-1)
# ==========================================================================
# Determine next line to be read
# Returning file minus the first line
# ==========================================================================
if (is.null(attr(file, "last_read_line"))) {
attr(file, "last_read_line") <- 1
} else {
attr(file, "last_read_line") <- attr(file, "last_read_line") + 1
}
# ==========================================================================
# Returning next line
# ==========================================================================
out <- file[attr(file, "last_read_line")]
out <- file[-1]
return(out)
}
@ -29,5 +22,6 @@ fgetl <- function(file) {
#' @param filename Path and name of file to be open
#' @return The same as `readLines(filename)`
#' @author Waldir Leoncio
#' @seealso fgetl
#' @export
fopen <- function(filename) readLines(filename)