New R package: a dictionary with arbitrary keys and values

March 11, 2016

(This article was first published on bioCS, and kindly contributed to R-bloggers)

Coming from Python, the absence of a real dictionary in R has annoyed me for quite some time. Now, I actually needed to use vectors as keys in R:


d <- dict()

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


# [[ ]] gives an error for unknown keys

Under the hood, separate C++ dictionaries (unordered_map) are created for the different types of keys. Using R’s flexible types that are reflected in Rcpp (as SEXP), such a dictionary can store both numbers and strings (and other objects) at the same time.

The package is available on GitHub:

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