How to get a hash code as integer in R?

问题

What I want to do is implement a hash trick in R.

Code below:

library(digest)
a<-digest("key_a", algo='xxhash32')
#[1] "4da5b0f8"

This returned a hash code in a character type. Is there any way I can turn it into a integer? Or is there any other package to achieve this?

回答1:

That output is a hex (base 16) string. Use following function to change it to decimal. Taken from another forum post but link does not work anymore (2017).

hex_to_int = function(h) {
  xx = strsplit(tolower(h), "")[[1L]]
  pos = match(xx, c(0L:9L, letters[1L:6L]))
  sum((pos - 1L) * 16^(rev(seq_along(xx) - 1)))
}

Output

> hex_to_int(a)
[1] 1302704376

But better answer is strtoi: as @Andrie said and @Gedrox answered, base::strtoi function works in the same way.

strtoi("4da5b0f8", 16)
[1] 1302704376

回答2:

There is a built in function base::strtoi:

> strtoi("4da5b0f8", 16)
[1] 1302704376

来源：https://stackoverflow.com/questions/27442991/how-to-get-a-hash-code-as-integer-in-r