Engine

MemoryStoreSortedMap

Show Deprecated
not creatable
not replicated

Provides access to a sorted map within MemoryStore. A sorted map is a collection of items where string keys are associated with arbitrary values (up to the maximum allowed size -- see Memory Stores). Each item can also have an optional sort key, which can be a number or a string. In the ordering of items, the sort key, if provided, takes precedence over the key. Items with numeric sort keys are sorted before items with string sort keys, which are sorted before items with no sort key. Items with the same sort key and items with no sort key are arranged in alphabetical order by key.

Summary

Methods

Properties

Methods

GetAsync

yields

Retrieves the value and sort key of a key in the sorted map.

Parameters

key: string

Key whose value and sort key to retrieve.


Returns

A tuple of two values:

  • Key value, or nil -- if there's no item with the specified key.
  • Sort key, or nil -- if there's no sort key associated with the specified key.

GetRangeAsync

yields

Gets items within a sorted range of keys and sort keys.

Parameters

Sort direction, ascending or descending.

count: number

The number of items to retrieve; the maximum allowed value for this parameter is 200.

exclusiveLowerBound: Variant

(Optional) Lower bound, exclusive, for the returned keys. This is provided as a table where one or both of key and sort key can be specified: { key: string, sortKey: Variant } .

exclusiveUpperBound: Variant

(Optional) Upper bound, exclusive, for the returned keys. This is provided as a table where one or both of key and sort key can be specified: { key: string, sortKey: Variant } .


Returns

Item keys, values and sort keys in the requested range.

Code Samples

Retrieving MemoryStore Keys

local MemoryStoreService = game:GetService("MemoryStoreService")
local myMap = MemoryStoreService:GetSortedMap("MySortedMap")
function printAllKeys(map)
-- the initial lower bound is nil which means to start from the very first item
local exclusiveLowerBound = nil
-- this loop continues until the end of the map is reached
while true do
-- get up to a hundred items starting from the current lower bound
local items = map:GetRangeAsync(Enum.SortDirection.Ascending, 100, exclusiveLowerBound)
for _, item in ipairs(items) do
print(item.key)
print(item.sortKey)
end
-- if the call returned less than a hundred items it means we've reached the end of the map
if #items < 100 then
break
end
-- the last retrieved key is the exclusive lower bound for the next iteration
exclusiveLowerBound = {}
exclusiveLowerBound["key"] = items[#items].key
exclusiveLowerBound["sortKey"] = items[#items].sortKey
end
end
printAllKeys(myMap)

RemoveAsync

void
yields

Removes the provided key from the sorted map.

Parameters

key: string

Key to remove.


Returns

void

SetAsync

yields

Sets the value and sort key of the key overwriting any existing key value and sort key.

Parameters

key: string

Key whose value to set.

value: Variant

Key value to set.

expiration: number

Item expiration, in seconds. The item is automatically removed from the sorted map once the expiration duration is reached. The maximum expiration time is 45 days (3,888,000 seconds).

sortKey: Variant

(Optional) Sort key to set for this key. Accepted types are a number (integer or decimal) or a string.


Returns

UpdateAsync

yields

Retrieves the value and sort key of a key from a sorted map and lets you update it to a new value and sort key via a callback function.

This method accepts a callback function that transforms the old value and old sort key into the updated value and updated sort key as required. The method retrieves the existing key value and sort key and passes it to the transform function which returns the new value and sort key for the item, with these exceptions:

  • If the key does not exist, the old value and old sort key passed to the function will be nil.
  • If the function returns nil, the update is canceled.

The new value and new sort key is saved only if the key was not updated (e.g. by a different game server) since the moment it was read. If the value or sort key did change, the transform function is invoked again with the most recent item value and sort key. This cycle repeats until the value and sort key are saved successfully or the transform function returns nil to abort the operation.

Parameters

key: string

Key whose value to update.

transformFunction: function

A function which you need to provide. The function takes the key's old value and old sort key as input and returns the new value and new sort key.

expiration: number

Item expiration time, in seconds, after which the item will be automatically removed from the sorted map. The maximum expiration time is 45 days (3,888,000 seconds).


Returns

The return value is a tuple of the last value and sort key returned by the transform function.

Code Samples

Updating a MemoryStore

local MemoryStoreService = game:GetService("MemoryStoreService")
local map = MemoryStoreService:GetSortedMap("Leaderboard")
local Players = game:GetService("Players")
function updateLeaderboard(itemKey, killsToAdd, deathsToAdd)
local success, newStats, newScore = pcall(function()
return map:UpdateAsync(itemKey, function(playerStats, playerScore)
playerStats = playerStats or { kills = 0, deaths = 0 }
playerStats.kills += killsToAdd
playerStats.deaths += deathsToAdd
if playerStats then
-- `playerScore` is the sortKey being used to sort items in the map
playerScore = playerStats.kills / math.max(playerStats.deaths, 1)
return playerStats, playerScore
end
return nil
end, 30)
end)
end
-- Add one kill to all players
for i, player in pairs(Players:GetPlayers()) do
updateLeaderboard(player.UserId, 1, 0)
end
-- Add 5 kills and 1 death to player with userId 12345
updateLeaderboard(12345, 5, 1)

Events