Can someone explain how exactly to work with dictionaries?

Help and Feedback Scripting Support
#1

I’ve already browsed the DevHub but I wanna see if anyone else can explain it a little better. This is an excerpt from a script I found:

local PlayerRunning = {}
sprintingPlayers[player.Name] = humanoid.WalkSpeed
		humanoid.WalkSpeed = humanoid.WalkSpeed * sprintModifier
	elseif state == "Ended" and sprintingPlayers[player.Name] then
		humanoid.WalkSpeed = sprintingPlayers[player.Name]
		sprintingPlayers[player.Name] = nil

How does the script know what the humanoid walkspeed is from the bracket “Player.Name” alone? Previously the dictionary or table (if there’s a difference between the 2, let me know) isn’t clearly defined.

Another time it’s used in the script is here:

local name = player.Name
player.Character.Humanoid.WalkSpeed = sprintingPlayers[name]

Here it’s setting the Humanoid’s WalkSpeed to the player’s name? What’s up with that? Nice detailed explanation of how they work would be nice.

#2

This is setting a key-value pair, the player’s name being the key, mapped to the walk speed, which is the value. Indexing a table with a key returns the value, not the key.

So this is setting their walk speed to whatever number the player’s name is mapped to in the table.

#3

So the bracket beside the table is either assigning a key to it or is used as a reference for a player property?

#4

You can think of them like a drawer with infinite space, and each item in it is labeled.

For example, lets say you store a value with dictionary[Player.Name] = 10. The player is named “Player1”.
Now the dictionary looks like this:

{
     Player1 = 10
}

If you want to read a value in a dictionary you can either use a dot or brackets. Brackets can use variables, a dot cannot. eg

--Player.Name is "Player1"
print(dictionary.Player1) --10
print(dictionary[Player.Name]) --10

In your case sprintingPlayers would look like

{
    PlayerName = number
}

and sprintingPlayers[name] would then get the value in the dictionary, here used for the original walk speed.

#5

Both. You can also use table.insert() for dictionaries as well.

#6

Table.insert() and table[] does the same thing?

#7

Yes, but if you try to table[] an array, it will give you an error.

#8

table.insert(table, value) will treat the table as an array, making the table look like

--table.insert(table, "hi")
--table.OtherKey = "othervalue"
{
    [1] = "hi"
    OtherKey = "othervalue"
}
#9

To add up, it’s not kinda like the same. table.insert is meant to insert a value to a table, while table[] on dictionaries do is index an existing key to get the key’s value or create a new key name.

1 Like
#10

Ah I understand now, thank you all kindly for the splendid help.

#11

This is a basic understanding of table btw. Try to read more from developer.roblox.com