https://github.com/decisionpatterns/r-hash

Full feature implementation of hash/associated arrays/dictionaries in R
https://github.com/decisionpatterns/r-hash

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Full feature implementation of hash/associated arrays/dictionaries in R

• Host: GitHub
• URL: https://github.com/decisionpatterns/r-hash
• Owner: decisionpatterns
• License: other
• Created: 2013-12-01T19:43:54.000Z (almost 12 years ago)
• Default Branch: master
• Last Pushed: 2019-02-05T16:10:00.000Z (over 6 years ago)
• Last Synced: 2024-08-13T07:15:26.704Z (about 1 year ago)
• Language: R
• Size: 148 KB
• Stars: 29
• Watchers: 4
• Forks: 3
• Open Issues: 6
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# hash 

## hash/dictionary/maps in R

![](https://img.shields.io/cran/v/hash.svg)  

![](https://img.shields.io/cran/l/hash.svg)  

[![lifecycle](https://img.shields.io/badge/lifecycle-stable-brightgreen.svg)](https://www.tidyverse.org/lifecycle/#stable)

[![Downloads](https://cranlogs.r-pkg.org/badges/hash?color=brightgreen)](https://www.r-pkg.org/pkg/hash)

[![](http://cranlogs.r-pkg.org/badges/grand-total/hash)](https://cran.r-project.org/package=hash)

The *hash* package provides a fully-functional hash/dictionaryfor the R language. It provides richer features and finer control of hash behavior than using native R structures like list or environments and has as a user-friendly interface. Performance-wise it has similar and sometimes better performance than these structures especially for larger objects.

## Installation

Latest Release:

    install.packages('hash')

Development Version:

    install.packages('devtools')

    devtools::install_github('decisionpatterns/r-hash')

## Examples 

    # Create a hash 

    h <- hash(a=1, b=2, c=3)

    h <- hash( letters[1:3], 1:3 )

    h <- hash( list(a=1,b=2,c=3) )  

     

    # Keys 

    keys(h)

     

    # Values (named list)

    values(h)

     

    # Assign to single key hash

    h$a <- "foo"

    h[['a']] <- "bar"

     

    # Slice

    h[ c('a','c') ]

    

## Allowable Values  

**KEYS** must be a valid character value and may not be the empty string (""). Keys must be unique.

**VALUES** can be any R value, vector, object, etc. 

## Usage Notes

Hashes probably work about how you would expect, but since there are built from R's native environments. There are three things to Remember:

**PASS-BY REFERENCE**. hashes are environments, special objects in R where only one copy exists globally. When passed as an argument to a function, no local copy is made and any changes to the hash in the functions are reflected globally, i.e. in the caller's namespace.

**PERFORMANCE**.  Hashes are designed to be exceedingly fast using R environment's internal hash table.  The hash function is not without its cost. For small data structures, a named lists and vectors will out-perform a hash in nearly every case. After approximately 500+ elements, the performance of the hash becomes faster than native lists and vectors.