Multiple Parameters and Arguments

Functions can actually have more than one parameter, allowing for multiple arguments (pieces of information), to be passed into the function. A game example might be assigning a player to a team. Here you would need a parameter to pass in the player, and a parameter to pass in which team to assign them to.

To set up multiple parameters, separate the parameter names with a comma.

local function assignTeam(playerName, whichTeam)



end

Practice with Multiple Parameters

To practice working with multiple parameters, create a function that sorts objects in your game into trash or recycling.

  • The first parameter will be trash, which will be destroyed.
  • The second parameter will be for recycling, which will be made shiny and new again.

Set Up the Function

First set up the function with multiple parameters and then test your work.

  1. Create a new script in ServerScriptService.
  2. Code a new function named sortGarbage() with two parameters, trash and recyclable.
  3. At the bottom of the script, call the function.
  4. Quickly check the code so far using a print statement inside the function.
local function sortGarbage(trash, recyclable)

   print("garbage test")

end



sortGarbage()

Using Multiple Parameters

Inside the function, parameters can be used similar to variables. In this example, trash is destroyed and then recyclable is given sparkles using a Particle Emitter.

  1. Delete the print statement, and use Instance.new() to create a new Particle Emitter as shown. This will be used to give recyclables their sparkle.

    local function sortGarbage(trash,recyclable)

        -- Create a new Particle Emitter

        local sparkle = Instance.new("ParticleEmitter")

    

    end

    

    sortGarbage()

  2. Destroy whatever is passed in through the trash parameter the same as if trash were any other variable.

    local function sortGarbage(trash,recyclable)

        local sparkle = Instance.new("ParticleEmitter")

    

        -- Destroy the trash

        trash:Destroy()

    end

    

    sortGarbage()

  3. Parent the Particle Emitter to the recyclable.

    local function sortGarbage(trash,recyclable)

        local sparkle = Instance.new("ParticleEmitter")

    

        -- Destroy the trash and make recyclables shiny

        trash:Destroy()

        sparkle.Parent = recyclable

    end

    

    sortGarbage()

Passing Values Through Parameters

Time to take out the trash! With the parameters set up, the functions are ready to take in information.

  1. Create two objects using basic parts to represent things you might throw away. One should be trash and one recyclable. Make sure they have unique names.

  2. At the top of the script, add variables for the objects you created. These will be your arguments.

    local cementBlock = workspace.Cement

    local glassBottle = workspace.GlassBottle

  3. At the bottom of the script, where sortGarbage() is called, pass in each argument.

    -- Objects to use as arguments

    local cementBlock = workspace.CementBlock

    local glassBottle = workspace.GlassBottle

    

    --Destroys trash and cleans up recyclables

    local function sortGarbage(trash,recyclable)

        local sparkle = Instance.new("ParticleEmitter")

    

        trash:Destroy()

        sparkle.Parent = recyclable

    end

    

    -- Pass in the arguments

    sortGarbage(cementBlock, glassBottle)

  4. Test your code. The object passed in first will be destroyed. The second object will sparkle.

Order of Parameters

Typically, arguments are matched to parameters based on the order they're passed in. For instance, the first argument is used for the first parameter. The second argument is used for the second.

In our example, there are two parameters. Whatever gets passed in first will always be trash, and the second will always be recyclable.

--Destroys trash and cleans up recyclables

local function sortGarbage(trash,recyclable)

     local sparkle = Instance.new("ParticleEmitter")



    trash:Destroy()

    sparkle.Parent = recyclable

end



--Goes in order. Cement is destroyed and the glass bottle is recycled

sortGarbage(cementBlock, glassBottle)



--GlassBottle is destroyed and cementBlock is recycled

sortGarbage(glassBottle, cementBlock)

If you were to only pass in only one argument, that argument would be treated as trash. If you were to pass in three arguments, nothing would happen to the third argument because there is no third parameter.

Summary

Parameters are placeholders through which values can be passed into functions. Arguments are the values that get passed through the placeholder. You can create multiple parameters by separating their names with commas. When calling functions, the order that values get passed into the receiving function determines which parameter they're used.

Precedente
Prossimo