hash {rlang}

Hashing

Description

• hash() hashes an arbitrary R object.

• hash_file() hashes the data contained in a file.

The generated hash is guaranteed to be reproducible across platforms that have the same endianness and are using the same R version.

Usage

hash(x)

hash_file(path)

Arguments

x

An object.

path

A character vector of paths to the files to be hashed.

Details

These hashers use the XXH128 hash algorithm of the xxHash library, which generates a 128-bit hash. Both are implemented as streaming hashes, which generate the hash with minimal extra memory usage.

For hash(), objects are converted to binary using R's native serialization tools. On R >= 3.5.0, serialization version 3 is used, otherwise version 2 is used. See serialize() for more information about the serialization version.

Value

• For hash(), a single character string containing the hash.

• For hash_file(), a character vector containing one hash per file.

Examples

hash(c(1, 2, 3))
hash(mtcars)

authors <- file.path(R.home("doc"), "AUTHORS")
copying <- file.path(R.home("doc"), "COPYING")
hashes <- hash_file(c(authors, copying))
hashes

# If you need a single hash for multiple files,
# hash the result of `hash_file()`
hash(hashes)