Invalidate Memo

Invalidates cached values for a memoized function without affecting unrelated memo entries in shared storage.

Call without key to invalidate all cached values for that memo only. Pass key to invalidate a single cached call:

• a named/unnamed list of function arguments

• a single character cache key hash

invalidate(f, key = NULL)

Arguments

f

memo function

key

optional cache key selector for single-entry invalidation

Value

Invisibly returns the memo function

Examples

library(magrittr)

base.dir <- file.path(tempdir(), "memofunc-example-invalidate")
unlink(base.dir, recursive = TRUE, force = TRUE)

old.options <- options(memofunc.storage.provider = list(name = "file", base.dir = base.dir))

counter <- new.env(parent = emptyenv())
counter$executed <- 0

expensive <- function (value) {
  counter$executed <- counter$executed + 1
  value * 10
}

memo.expensive <- memo(expensive, id = "invalidate-example")

# warm cache for two keys
memo.expensive(1)
#> [1] 10
memo.expensive(2)
#> [1] 20

# invalidate a single entry by arguments
invalidate(memo.expensive, list(value = 1))

counter$executed <- 0
memo.expensive(1)
#> [1] 10
memo.expensive(2)
#> [1] 20
counter$executed
#> [1] 1

# invalidate all entries for this memo only
invalidate(memo.expensive)

counter$executed <- 0
memo.expensive(1)
#> [1] 10
memo.expensive(2)
#> [1] 20
counter$executed
#> [1] 2

options(old.options)
unlink(base.dir, recursive = TRUE, force = TRUE)