Week 6

This week was pretty hectic for computer science. Not so much the lectures, but moreso an emphasis on the assignment 1. I had been stuck on part 5 for so long, and I didn't know what to do. Therefore, I had to go to one of the help sessions in order to finally get a clue and finish it. Thankfully, I managed to get it done (and the best solution, too) before the deadline.

As for the lectures, we went over trees (more recursion). We learned many things like leafs, nodes, subtree, height, and went over how to write a recursive function to gather this data from a Tree class. I feel that I'm slowly but surely getting recursion better and better, but it can still be a headache sometimes.

Although I have a generally feel towards these topics, I still believe I need to work harder in order to get a better grasp of recursion. Good luck to myself, I suppose.

P.S. the lab was fairly easy this week. However, I need to work on writing test cases. They can be confusing sometimes. >.<

Week 5

In this week, we went over recursion some more, and I really think I'm finally starting to get it. On Monday, we went over the process of writing a recursive program for the movement of cheeses on three stools. I'm sure this is going to be useful for my assignment, but I'm still worried about how to write a program for four stools. Anyway, on Wednesday, we touched on names and where local, nonlocal, global, and built in module names stand on the name hierarchy.

def scope_test():
    def do_local(): # nested function --- only available inside scope_test()
        spam = "local spam"
    def do_nonlocal():
        nonlocal spam
        spam = "nonlocal spam"
    def do_global():
        global spam
        spam = "global spam"
    spam = "test spam"
    do_local()
    print("After local assignment:", spam)
    do_nonlocal()
    print("After nonlocal assignment:", spam)
    do_global()
    print("After global assignment:", spam)

nonlocal turns the name spam into a local name inside the function scope_test

global turns the name spam into a global name in the entire module.

As for our lab, we worked on more recursion. I was happy that I was able to finish both of the required functions as well as one of the bonus ones. Here is the code if anyone is interested.

def find_num(SL: 'SearchList', n: int) -> bool:

    if n < SL[0]:
        return (find_num(SL[1], n) if isinstance(SL[1], list) else False)
    elif n > SL[0]:
        return (find_num(SL[2], n) if isinstance(SL[2], list) else False)
    elif n == SL[0]:
        return True
    
def freeze(x: object) -> object:

    if isinstance(x, list):
        return [freeze(item) if isinstance(item, list) else item for\
                item in x]
    else:
        return x    

def rev_string(s):

    string = ''
    for x in range(len(s) - 1, -1, -1):
        string += s[x]
    return string

p.s. we touched on methods a little bit more. 

class a:
    def b():

        return 2

if I did a.b(), it would return 2.
however, if I did this:
c = a()
c.b()

I would get an error because now the class a has an argument now, which is the name c.