How to read a counter key value pair from python in R?

Question

I have data generated from a Python script where the entries look like:

Counter({'a': 3, 'b': 2})

or

Counter({'a': 4, 'b': 1, 'c': 7})

If the above are read as characters in R, how can I extract the values into a single vector or other object that R can read? So, in the second example, we would have:

c('a','a','a','a','b','c','c','c','c','c','c','c')

Answer 1

It's close enough to json that I think we can use jsonlite to help:

S <- "Counter({'a': 4, 'b': 1, 'c': 7})"
gsub("'", '"', gsub("^Counter\\(|\\)$", "", S))
# [1] "{\"a\": 4, \"b\": 1, \"c\": 7}"
S2 <- jsonlite::fromJSON(gsub("'", '"', gsub("^Counter\\(|\\)$", "", S)))
S2
# $a
# [1] 4
# $b
# [1] 1
# $c
# [1] 7
rep(names(S2), times = unlist(S2))
#  [1] "a" "a" "a" "a" "b" "c" "c" "c" "c" "c" "c" "c"