Unset a value that corresponds to a key within a store.

Unsets the value stored for a given key.

If there is no value for the key provided no action is taken.

storage.unset(storage, key)

Arguments

storage

initialized storage

key

key whose value is to be unset

Value

Invisibily returns storage

Examples

library(magrittr)

# initialize default memory storage
my.storage <- storage.init()

# set a value into storage
storage.set(my.storage, "name", "Roy Wetherall")

# .. and some more
my.storage %>% 
  storage.set("age", 45) %>% 
  storage.set("alive", TRUE) %>%
  storage.set("children", c("Peter", "Grace", "Lucy"))

# check a key has been set
if (storage.has(my.storage, "name")) print("I know your name!")
#> [1] "I know your name!"

# .. and that a key hasn't been set
if (!storage.has(my.storage, "address")) print("I don't know where you live!")
#> [1] "I don't know where you live!"

# get some values from storage
sprintf(
  "%s is %i years old.", 
  storage.get(my.storage, "name"),
  storage.get(my.storage, "age"))
#> [1] "Roy Wetherall is 45 years old."

# remove a value from storage
storage.unset(my.storage, "children")

# .. and show it's not there anymore
if (!storage.has(my.storage, "address")) print("I don't know who your children are!")
#> [1] "I don't know who your children are!"

# clear all values from storage
storage.clear(my.storage)

# .. and everything is gone
if (!storage.has(my.storage, "name") && !storage.has(my.storage, "age")) print("I know nothing!")
#> [1] "I know nothing!"

# initialize file storage (direct backend; simplest local-only path)
base.dir <- file.path(tempdir(), "memofunc-storage")
file.storage <- storage.init("file", base.dir = base.dir)

# set and retrieve a value from file storage (direct backend)
storage.set(file.storage, "name", "Roy Wetherall")
storage.get(file.storage, "name")
#> [1] "Roy Wetherall"

# initialize object storage using a provider name (provider-backed interface)
# this uses the same local file backend now, but lets you swap to azure.blob/s3 later
object.storage <- storage.init("object", provider = "file", base.dir = base.dir)
storage.set(object.storage, "name", "Roy Wetherall")
storage.get(object.storage, "name")
#> [1] "Roy Wetherall"

# set a default provider via options
old.options <- options(memofunc.storage.provider = list(name = "file", base.dir = base.dir))
on.exit(options(old.options), add = TRUE)
default.storage <- storage.init()
storage.get(default.storage, "name")
#> NULL

# Azure Blob provider example (requires AzureStor + credentials)
if (requireNamespace("AzureStor", quietly = TRUE)) {
  account <- Sys.getenv("AZURE_STORAGE_ACCOUNT")
  container <- Sys.getenv("AZURE_STORAGE_CONTAINER")
  key <- Sys.getenv("AZURE_STORAGE_KEY")
  token <- Sys.getenv("AZURE_STORAGE_TOKEN")

  if (account != "" && container != "" && (key != "" || token != "")) {
    azure.storage <- storage.init(
      "object",
      provider = "azure.blob",
      account = account,
      container = container,
      key = if (key == "") NULL else key,
      token = if (token == "") NULL else token,
      prefix = "memofunc-example"
    )

    storage.set(azure.storage, "name", "Roy Wetherall")
    storage.get(azure.storage, "name")
  }
}