CS145 Midterm Review #2: 17b_notes.py

17b_notes.py

# 17b_notes.py

## Recursion Breakdown

def countdown(n: int):
    print("begin: countdown(",n,")")
    if n == 0:
        print("output:\t\tBlastoff!")
    else:
        print("before:\t\t", n)
        countdown(n-1)
        print("after:\t\t", n)
    print("finish: countdown(",n,")")

def q9():
    items = [1,2,3,7,4,7]
    k = 0
    while k < len(items):
        if items[k] == 7:
            print(items[k])
        k += 1
        
    print("---")
    for k in range(len(items)):
        if items[k] == 7:
            print(items[k])
            
    print("---")
    for it in items:
        if it == 7:
            print(it)

def for_loops():
    stuff = [1,2,3,4,7,3]
    output = []
    for name in stuff:
        if name == 7:
            output.append(name)
            break
    print(output)

def factors(n):
    keep = []
    for i in range(1, n+1):
        if n % i == 0:
            keep.append(i)
    return keep

def is_prime(n):
    return factors(n) == [1,n]

def line_count_file(file_name):
    
    with open(file_name, 'r') as file_var:
        total = 0
        for line in file_var:
            total += 1
            continue
        return total

def is_sorted(xs):
    for i in range(len(xs)-1):
        if xs[i] > xs[i+1]:
            return False
    return True

def sort_if_needed(xs):
    if is_sorted(xs):
        return xs
    xs.sort()
    return xs

def loops():
    numbers = [11, 2, 33, 4, 55, 6, 77, 8, 99]
    for x in numbers:
        if x < 11:
            continue
        if x > 50:
            break
        print(x * 10)

def aliasing_example():
    def add_c_to_list(second):
        second.append("c")

    first = ["a", "b"]
    # second = first
    # second.append("c")
    add_c_to_list(first)
    print(first)