https://github.com/privefl/mmapcharr

Memory-map text files of characters as R matrices
https://github.com/privefl/mmapcharr

Last synced: 3 months ago
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Memory-map text files of characters as R matrices

• Host: GitHub
• URL: https://github.com/privefl/mmapcharr
• Owner: privefl
• Created: 2017-12-07T09:08:59.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2019-02-26T09:12:01.000Z (over 5 years ago)
• Last Synced: 2024-05-21T02:53:37.317Z (6 months ago)
• Language: R
• Size: 2.72 MB
• Stars: 5
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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# mmapcharr

Memory-map text files of characters. 

## Installation

```r

# For the CRAN version

install.packages("mmapcharr")

# For the current development version

devtools::install_github("privefl/mmapcharr")

```

## Input format

As inputs, package **mmapcharr** uses text files of characters separated by another character.

Lines should be the same so that the file can be viewed as a matrix.

Files should end up with an empty line. 

You can play with the `code` parameter to access whatever you want instead of characters (see the example code below).

![An example of supported file](https://raw.githubusercontent.com/privefl/mmapcharr/master/example-file.png)

You can access files in such shape the same way as for R(cpp) matrices.

## Example code

```r

library(mmapcharr)

test_file <- system.file("testdata/test-windows.txt", package = "mmapcharr")

readLines(test_file)

# Create the memory-mapping object based on the text file

test <- mmapchar(test_file, code = mmapcharr:::CODE_012)

test[]

test[, 1:10]

# Underlying characters

(CHAR256 <- rawToChar(as.raw(0:255), multiple = TRUE))

# Change the code to access true characters

test2 <- test$copy(code = CHAR256)

test2[, 1:10]

# Change the code to access logicals (why not?)

test3 <- test$copy(code = rep(c(TRUE, FALSE), 256 / 2))

test3[, 1:10]

```

## Bug report / Help

Please open an issue if you find a bug.