Convert a Redis hash to a character vector or list. This tries to bridge the gap between the way Redis returns hashes and the way that they are nice to work with in R, but keeping all conversions very explicit.
from_redis_hash(
con,
key,
fields = NULL,
f = as.character,
missing = NA_character_
)A Redis connection object
key of the hash
Optional vector of fields (if absent, all fields are
retrieved via HGETALL.
Function to apply to the list of values retrieved
as a single set. To apply element-wise, this will need to be
run via something like Vectorize.
What to substitute into the returned vector for
missing elements. By default an NA will be added. A
stop expression is OK and will only be evaluated if
values are missing.
if (redux::redis_available()) {
# Using a random key so we don't overwrite anything in your database:
key <- paste0("redux::", paste(sample(letters, 15), collapse = ""))
r <- redux::hiredis()
r$HSET(key, "a", "apple")
r$HSET(key, "b", "banana")
r$HSET(key, "c", "carrot")
# Now we have a hash with three elements:
r$HGETALL(key)
# Ew, that's not very nice. This is nicer:
redux::from_redis_hash(r, key)
# If one of the elements was not a string, then that would not
# have worked, but you can always leave as a list:
redux::from_redis_hash(r, key, f = identity)
# To get just some elements:
redux::from_redis_hash(r, key, c("a", "c"))
# And if some are not present:
redux::from_redis_hash(r, key, c("a", "x"))
redux::from_redis_hash(r, key, c("a", "z"), missing = "zebra")
r$DEL(key)
}
#> [1] 1