Tutorial: Lists

By Deborah Nelson

Duke University, July 13, 2008

Under the direction of Professor Susan Rodger

As you follow the instructions below, click on an image to enlarge it.

Then use the'go back one page' arrow in your web browser to come back to this tutorial.

Loading the World

Open a new world, with the template of your choosing. Save it in a directory that you can find again. After you have opened the file, and set up your world, go into the "Layout" mode by clicking on the green button 'Add Objects' (toward the middle of screen)

Click 'more controls.' Click 'drop a dummy at the camera.' Rename the dummy 'originalPosition.' To leave the layout mode, click 'done' This is something you should always do when you make a world in case you need to return the camera to this view later. If you don't understand dummys,look at the camera control tutorial again.

Adding Objects

Go to the gallery and add four evilNinjas to your world (from the People folder)
Add two other people to your world.I’ve added the scientist-man and scientist-woman

Part 1: Making a list

We will use a list to make all four of the ninjas jump up and down together and then kick and spin one at a time .
Click on the world in the object tree and on the properties tab
Click create new variable. Name it ‘characters’

Select object as the type
Check the box make a List
Click the new item button four times

For item0 select evilNinja
For item1 select evilNinja2
For item2 select evilNinja3
For item3 select evilNinja4

Now, there is a characters list variable at the top of the world properties tab

Part 2: Writing the method

Drag for all together into world.my first method

In the drop down menu, select expressions, then select the list world.characters
For all together means that all of the items in the list will perform the instructions at the same time.

Step 1: For all together:

Click on item_from_characters and drag it on top of the Do nothing

In the drop down menu, select turn to face and then select camera
Click on more to change the duration to 0.25
Drag item_from_characters again and select the move up and move down instructions.
Play your world. Your method should look like this:

Step 2: For all in order:

Now drag for all in order underneath the for all together and select expressions, then world.characters

For all in order means the ninjas will perform all of the instructions, one right after the other (in the order that they were added to the list)
We want the ninjas to each turn their left leg and spin one at a time.
However, item_from_characters does not have any parts
We will have to use a class level built in function to turn just a part.
First, drag item_from_characters into the for all in order and select turn backward 1/4
Click on evilNinja in the object tree.
Select the functions tab and scroll down to evilNinja’s part named key
Drag that function on top of the item_from_character in your instruction

Step 3: Object part named key:

Drag that function on top of the item_from_character in your instruction

In the object tree, click on the + beside evilNinja to see that it’s body part is named leftLeg
In the turn backward instruction, click on the box and type leftLeg with the same capitalization and spacing as it appears in the object tree. No blank spacers, and the second L must be a capital letter

Drag item_from_characters on top of evilNinja

Drag item_from_characters into the for all in order again and select turn right 1 revolution

Then drag item_from_characters again and select turn forward Ľ. Your loop should look like this so far:

That last instruction should be for the leftLeg only.
So drag the function evilNinja’s part named key on top of the item_from_characters and type in leftLeg again.
Drag item_from_characters on top of evilNinja in the part named key

The complete method

Here is the complete method. Don’t forget to comment your code

Play your world
Below is a screenshot of the world playing