Multiple Conditions | Documentazione

Control structures can have more than one condition. The keywords else and elseif can create additional scenarios for what should happen under several conditions. The syntax looks like:

Shows syntax for elseif and else
if isGreen then
   print("Go")
elseif isYellow then
   print("Slow")
elseif isPedestrians then
   print("Wait")
else
   print("stop")
end

In this project, else and elseif are used to code a parkour course where runners receive awards depending on their finishing time.

Coding Multiple Conditions

For this project, you could write a unique if statement for each medal to award players, but that takes a lot of time. Take, for instance, the imaginary code below.

All if statements
if finishTime < 5  then
   -- Get a gold medal
end

if finishTime >= 5 and <= 10 then
   -- Get a silver medal
end

if finishTime > 10 and <= 15 then
   -- Get a bronze medal
end

A more readable and efficient way to code this is to use a single if statement and use the keyword elseif to provide alternative conditions to test if the previous conditions aren't true.

Uses elseif and else
if finishTime < 5  then
   -- Get a gold medal
elseif finishTime >= 5 and <= 10 then
   -- Get a silver medal
elseif finishTime > 10 and <= 15 then
   -- Get a bronze medal
end

When the if/then statement runs, it'll start at the top and only run the code for the first true condition it finds.

Setting Up the Race Course

Start by placing the course's starting point and finish line, and then create a script to time the player and award different medals.

Create an anchored part named FinishLine. To make testing faster, place the start and end close together. You can move the finish line after finishing the script.

Finish Part
Entire Course
In FinishLine, insert a script named RaceManager. Then, add one variable to store how many seconds have passed since the race started and a second variable to reference FinishLine.
```
local finishLine = script.Parent
   local timePassed = 0
```

Create a function named finish().


local timePassed = 0
local finishLine = script.Parent

local function finish()

end

On your own:

Code a function named partTouched() that runs finish() when a player touches it.
Connect the finish line part to partTouched().
Compare your code to the example below.


local function finish()
   print("touched the finish line")
end

local function partTouched(otherPart)
   local character = otherPart.Parent
   local humanoid = character:FindFirstChildWhichIsA("Humanoid")
   if humanoid then
      finish()
   end

end

finishLine.Touched:Connect(partTouched)

Playtest and check that finish() is called when you touch the finish line.

Keep finish() From Repeating

Right now, whenever a player touches the finish line, finish() gets continuously called as long as the player touches the part.

Use a boolean, a variable that stores true or false, to ensure that finish() is only called once.

Create a new variable named raceActive and set it to true.


local timePassed = 0
local finishLine = script.Parent

local raceActive = true

-- Runs whenever the player touches the finish line part
local function finish()

Add a second condition to the if statement to check if raceActive is true before calling finish().


local function partTouched(otherPart)
   local character = otherPart.Parent
   local humanoid = character:FindFirstChildWhichIsA("Humanoid")
   if humanoid and raceActive == true then
      finish()
   end

end

To stop finish() from being called again, set raceActive to false.


local function finish()
   print("touched the finish line")
   raceActive = false
end

Playtest your game to check that you only see your test print statement once.

Keeping Track of Time

Like an if statement, a while loop can also use a condition to see if it should run. To time the player, create a timer using a while true do loop that only runs when the raceActive boolean is true.

At the bottom of the script, type while raceActive == true do. Press Enter to auto-complete and add the end.
```
finishLine.Touched:Connect(partTouched)

while raceActive == true do

end
```
Make sure the loop is at the bottom of the script. Even though this while true do loop, eventually stops, it should still stay at the bottom of the script. This ensures that the previous code runs before it reaches the loop.

To time the players, in the loop, add 1 to the timePassed variable once every second. Include a print statement to test your work.


finishLine.Touched:Connect(partTouched)

while raceActive == true do
   task.wait(1)
   timePassed += 1
   print(timePassed)
end

Play the game and check that you see each second displayed in the Output Window.

To finish, use an if statement with multiple conditions to award players a different prize medal based on their performance. Use an if statement and two elseif statements to check the player's finish time and award them the correct medal.

To confirm each medal can be awarded, use print statements.


local function finish()
   raceActive = false
   print("You finished in " .. timePassed)
end

To award a gold medal, code an if statement that compares timePassed to the desired finish time. This example checks if the player's time was less than or equal to 10 seconds.


local function finish()
   raceActive = false
   print("You finished in " .. timePassed)

   if timePassed <= 10 then
      print("You get a gold medal!")
   end
end

Playtest and confirm the gold medal can be awarded.

Adding Additional Conditions

Now that you've tested for the gold medal, code conditions for the other medals using the elseif keyword.

For the silver medal, use elseif and the next desired time range. In this example, the range is greater than 10 seconds but less than or equal to 20 seconds.


local function finish()
  raceActive = false
  print("You finished in " .. timePassed)

  if timePassed <= 10 then
    print("You get a gold medal!")
  elseif timePassed > 10 and timePassed <= 20 then
    print("You get a silver medal!")
    end
end

Use the same pattern for the bronze medal. Check your code with the example below.


local function finish()
   raceActive = false
   print("You finished in " .. timePassed)

   if timePassed <= 10 then
      print("You get a gold medal!")
   elseif timePassed > 10 and timePassed <= 20 then
      print("You get a silver medal!")
   elseif  timePassed > 20 and timePassed <= 30 then
      print("You get a bronze medal!")
   end
end

Playtest for the silver and bronze medals.

Troubleshooting Tips

If you don't see the silver and bronze metals appear, try one of the below.

Each elseif should have a then after its condition.
In partTouched(), make sure the second condition of the if statement uses ==, like in raceActive == true.
Check that each elseif is in scope. Each elseif condition must be between the first line of the if/then statement and it's last end.

Adding the Else Condition

If the player didn't earn any of the medals, you should encourage them to try again. In this case, you can use an else statement, which runs if no other conditions are true, to show them a message.

It's recommended that every if statement has an else, just in case the code doesn't find anything true.

Below the last elseif and above end, start a new line and type else. Do not add then. Beneath else, use a print statement to prompt them to try again.


local function finish()
  raceActive = false
  print("You finished in " .. timePassed)

  if timePassed <= 10 then
    print("You get a gold medal!")
  elseif timePassed > 10 and timePassed <= 20 then
    print("You get a silver medal!")
  elseif  timePassed > 20 and timePassed <= 30 then
    print("You get a bronze medal!")
  else
    print("Try again!")
  end
end

An else statement should always be the last check in an a control structure.

2 . Playtest to see the else message.

Summary

Control structures can have more than one scenario. Use if statements to set up the initial statement to check, and then add as many elseif conditions as necessary. Finally, use else to state what should happen if all given conditions are false.

Starting at the top, all conditions will be checked, and only the first true condition will run the code. The remaining conditions will not be checked, nor will their code run.

After finishing the project, you can expand upon the script to add new elements in a few extra ways.

Add code so players can repeat the race by touching the start line when they finish.
Design a way to display time during a race. You can either display the time on a part using a Surface GUI, like in the Creating a Timed Bridge tutorial.

Completed script
local timePassed = 0
local finishLine = script.Parent

-- Used to keep finish() and timer from repeating when race is over
local raceActive = true

-- Runs when the player touches the finish line and shows them an award
local function finish()
   raceActive = false
   print("You finished in " .. timePassed)

   if timePassed <= 10 then
      print("You get a gold medal!")
   elseif timePassed > 10 and timePassed <= 20 then
      print("You get a silver medal!")
   elseif  timePassed > 20 and timePassed <= 30 then
      print("You get a bronze medal!")
   else
      print("Try again!")
   end
end


-- Checks if a player touches the part when a race is active
local function partTouched(otherPart)
   local character = otherPart.Parent
   local humanoid = character:FindFirstChildWhichIsA("Humanoid")
   if humanoid and raceActive == true then
      finish()
   end

end

finishLine.Touched:Connect(partTouched)

-- Keeps track of race time while the race is active. Needs to be at script bottom.
while raceActive == true do
   task.wait(1)
   timePassed += 1
   print(timePassed)
end