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<!-- README.md is generated from README.Rmd. Please edit that file -->
# brio - Basic R Input Output
<!-- badges: start -->
[](https://app.codecov.io/gh/r-lib/brio?branch=master)
[](https://github.com/r-lib/brio/actions)
<!-- badges: end -->
Functions to handle basic input output, these functions always read and
write UTF-8 files and provide more explicit control over line endings.
## Reading files
``` r
library(brio)
#>
#> Attaching package: 'brio'
#> The following objects are masked from 'package:base':
#>
#> readLines, writeLines
write_lines(c("abc", "123"), "my-file")
# Write with windows newlines
write_lines(c("abc", "123"), "my-file-2", eol = "\r\n")
file_line_endings("my-file")
#> [1] "\n"
file_line_endings("my-file-2")
#> [1] "\r\n"
read_lines("my-file")
#> [1] "abc" "123"
unlink(c("my-file", "my-file-2"))
```
## Drop-ins
brio also has `readLines()` and `writeLines()` functions drop-in
replacements for `base::readLines()` and `base::writeLines()`. These
functions are thin wrappers around `brio::read_lines()` and
`brio::write_lines()`, with deliberately fewer features than the base
equivalents. If you want to convert a package to using brio you can add
the following line and re-document.
``` r
#' @importFrom brio readLines writeLines
```
## Benchmarks
Speed is not necessarily a goal of brio, but it does end up being a nice
side effect.
``` r
gen_random <- function(characters, num_lines, min, max) {
line_lengths <- sample.int(max - min, num_lines, replace = TRUE) + min
vapply(line_lengths, function(len) paste(sample(characters, len, replace = TRUE), collapse = ""), character(1))
}
set.seed(42)
# generate 1000 random lines between 100-1000 characters long
data <- gen_random(letters, 1000, min = 100, max = 1000)
brio::write_lines(data, "benchmark")
```
### Reading
Reading speeds are a decent amount faster with brio, mainly due to
larger block sizes and avoidance of extra copies.
``` r
bench::mark(
brio::read_lines("benchmark"),
readr::read_lines("benchmark"),
base::readLines("benchmark")
)
#> # A tibble: 3 × 6
#> expression min median `itr/sec` mem_alloc `gc/sec`
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 brio::read_lines("benchmark") 676.56µs 694.67µs 1382. 8.05KB 0
#> 2 readr::read_lines("benchmark") 3.87ms 4.19ms 235. 7.2MB 8.70
#> 3 base::readLines("benchmark") 3.68ms 3.92ms 250. 31.39KB 0
```
### Writing
Write speeds are basically the same regardless of method, though brio
does avoid some extra memory allocations.
``` r
bench::mark(
brio::write_lines(data, "benchmark"),
readr::write_lines(data, "benchmark"),
base::writeLines(data, "benchmark"),
check = FALSE
)
#> # A tibble: 3 × 6
#> expression min median `itr/sec` mem_alloc
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt>
#> 1 brio::write_lines(data, "benchmark") 833.8µs 1.3ms 751. 0B
#> 2 readr::write_lines(data, "benchmark") 11.86ms 13ms 76.5 195KB
#> 3 base::writeLines(data, "benchmark") 1.07ms 1.52ms 636. 0B
#> # … with 1 more variable: gc/sec <dbl>
unlink("benchmark")
```
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