1. Nate Brunelle Today: Lists
CS1110
Nate Brunelle
Today: Lists

2. Questions?

3. Last Time
Loops in loops

4. Lists in lists
x=[[1, 2], [3, 4, 5], [6]] len(x) -> 3 x[1] -> [3,4,5] len(x[1]) -> 3 x[1][0] -> 3 len(x[1][0]) Error

5. Example of lists in lists
Pictures are:
A grid of pixels
A grid is:
A list of rows
A row is:
A list of pixels
A pixel is:
A list of 3 numbers (amounts of red, green blue)
So a picture is:
A list of lists of lists
rows of pixels of 3 numbers

6. Identity, Alias
Alias: another name for the same thing

7. New lists vs. Aliasing Creates a new list: Creates an Alias:
List-builder: [x, y, z]
Slicing: mylist[start:end:step]
Casting: list(collection)
Creates an Alias:
Assignment: mylist = myotherlist
Invoking a function: func(mylist)