https://github.com/nacnudus/lexl

An R package to tokenise Excel formulas
https://github.com/nacnudus/lexl

Last synced: about 1 month ago
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An R package to tokenise Excel formulas

• Host: GitHub
• URL: https://github.com/nacnudus/lexl
• Owner: nacnudus
• License: other
• Created: 2017-09-17T20:47:41.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2017-10-10T18:03:14.000Z (about 7 years ago)
• Last Synced: 2024-08-13T07:11:28.524Z (4 months ago)
• Language: R
• Homepage: https://nacnudus.github.com/lexl
• Size: 466 KB
• Stars: 4
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.Rmd
  • License: LICENSE

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• jimsghstars - nacnudus/lexl - An R package to tokenise Excel formulas (R)

README

        
---

output: github_document

---

```{r setup, include = FALSE}

knitr::opts_chunk$set(

  collapse = TRUE,

  comment = "#>",

  fig.path = "man/figures/README-"

)

```

# lexl

[![Travis build status](https://travis-ci.org/nacnudus/lexl.svg?branch=master)](https://travis-ci.org/nacnudus/lexl)

[![AppVeyor Build Status](https://ci.appveyor.com/api/projects/status/github/nacnudus/lexl?branch=master&svg=true)](https://ci.appveyor.com/project/nacnudus/lexl)

[![CRAN status](http://www.r-pkg.org/badges/version/lexl)](https://cran.r-project.org/package=lexl)

[![CRAN Downloads](https://cranlogs.r-pkg.org/badges/lexl)](https://www.r-pkg.org/pkg/lexl)

[![Coverage status](https://codecov.io/gh/nacnudus/lexl/branch/master/graph/badge.svg)](https://codecov.io/github/nacnudus/lexl?branch=master)

[lexl](https://github.com/nacnudus/lexl) separates Excel formulas into tokens of

different types, and gives their depth within a nested formula.  Its name is a

bad pun on 'Excel' and 'lexer'.  Try the [online

demo](https://duncan-garmonsway.shinyapps.io/lexl/) or run `demo_lexl()`

locally.

## Installation

You can install lexl from github with:

```{r gh-installation, eval = FALSE}

# install.packages("devtools")

devtools::install_github("nacnudus/lexl")

```

## Example

```{r, fig.width = 7, fig.height = 5}

library(lexl)

x <- lex_xl("MIN(3,MAX(2,A1))")

x

plot(x) # Requires the ggraph package

```

## Parse tree

Not all parse trees are the same.  The one given by `lex_xl()` is intended for

analysis, rather than for computation.  Examples of the kind of analysis that it

might support are:

* Detecting constants that have been embedded inside formulas, rather than in

  cells referred to by formulas.

* Revealing which functions and combinations of functions are most common.

* Untangling the dependencies between cells in a spreadsheet.

## Where to find specimen formulas

The [tidyxl](https://nacnudus.github.io/tidyxl) package imports formulas from

xlsx (spreadsheet) files.

The [Enron

corpus](https://figshare.com/articles/Enron_Spreadsheets_and_Emails/1221767)

contains thousands of real-life spreadsheets.

## Inspiration

[Research](https://drive.google.com/file/d/0B79P2Uym3JjvMjlaWWtnTWRLQmc/view?usp=sharing)

by Felienne Hermans inspired this package, and the related

[XLParser](https://github.com/spreadsheetlab/XLParser) project was a great help

in creating the grammar.