Problem 1: Comprehension Inception

Suppose I construct the below 2D array using list comprehension:

A = [[i+j for i in range(3)] for j in range(4)]

What would be the output of:

print([A[i][2] for i in range(len(A))])

Problem 2a: That’s No Moon (jk, it is)

• This is a coding problem. Work in pairs or trios on a single computer
  • Discuss your algorithm BEFORE YOU WRITE ANY CODE. Make sure everyone understands.
• You are working in Prob2.py
• Initial tasks:
  • Add a dark blue background rectangle to the window
  • Add a GImage of the moon.png image centered in the window

Problem 2b: Odd Pixels

• Swap who is typing!
• Extract the pixel array from the moon image
• This moon image is a grayscale image, so the Red, Green, and Blue components are always equal
• Looping over all the pixels, how many pixels are darker than a value of 30?

Problem 2c: Thresholding

• Swap who is typing!
• Modify your last code to actually update the pixels in the array
  • If they are darker than 30, set them to a perfectly black pixel
  • Otherwise, set them to a perfectly white pixel
• Pass the updated pixel array into GImage(pix_array) and add the result to the window
• Play around with the thresholds to see different effects
• Since you are adding it on top of the original, you can also play around with giving the pixels some transparency (or making them different colors!)

Warhol Patterns