dict

dict provides dictionaries with arbitrary keys and values for R. Other solutions in R, such as named lists, the hash package, or environments only let you use strings and, partially, numbers as keys. However, it is not possible to use vectors like c(1,2,3) or c("A", "B") as keys. This package provides efficient implementations of standard Python-style dictionaries and a defaultdict for numeric vectors.

Under the hood, it creates a separate C++ unordered_map for the following types:

• numeric (both single values and vectors)
• character (both single values and vectors)

Please refer to the introduction for an overview of the functions, or see below for a short usage example.

Installation

To install:

if (!require("devtools")) install.packages("devtools")
devtools::install_github("mkuhn/dict")

This has been tested on Mac OS X (using clang) and Ubuntu (using gcc 4.8). Older versions of gcc might not work, due to incomplete support of C++11. On Windows, you will need the new gcc 4.93 toolchain or wait until R 3.3.0, to be released mid-April 2016.

Usage

Usage of dict:

library(dict)

d <- dict()

d[[1]] <- 42
d[[c(2, 3)]] <- "Hello!"
d[["foo"]] <- "bar"
d[[1]]
d[[c(2, 3)]]
d$get("not here", "default")

d$keys()
d$values()
d$items()

# [[ ]] gives an error for unknown keys
d[["?"]]

Usage of numvecdict:

library(dict)

d <- numvecdict()

# initialize with vector
d[[c(2, 3)]] <- c(1,2,3)
d$append_number(c(2, 3), 4)
d[[c(2, 3)]]

# if the key doesn't exist: create new vector
d$append_number(1, 23)
d[[1]]