notes

iteration is when something is repeated. usually done using loops. REPEAT N TIMES is pseudocode for this.

LISTS: collection of data in a sequence that can be iterated through.

EX: fruits = ["apple", "banana", "kiwi", "pomegranate"]

LISTS ARE MUTABLE. you can add and remove items from a list.

Nested Lists: you can store lists inside lists for more complex data. can create sublists with this.

can iterate through sublists in list and then iterate through values in those sublists.

Exercise 1 

list = [1, 2, 3, 4, 5] # Print this list in reverse order
#list.reverse() also works 
for i in range(len(list)):
    print(i + 1)
    a = list.pop() # pop element at the end of list
    list.insert(i, a) # add new element with index val of last popped element

print(list)

1
2
3
4
5
[5, 4, 3, 2, 1]

Exercise 2 

list = [9, 8, 4, 3, 5, 2, 6, 7, 1, 0] # Sort this array using bubble sort

for i in list:
    for a in range(len(list) - 1): # for loops look at the first element and the element next to it
        if list[a] > list[a + 1]: # if the 1st element is larger than the 2nd one + 1
             list[a], list[a + 1] = list[a + 1], list[a] # position of 2 elements are swapped so larger element is in front
             # lesser element is in back
            


# list.sort() also works :/
print(list)

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

Quiz reflection

4) How can we add something to the end of a list?

(a) Use + sign

(b) The word Add

(c) Append

(d) Extend

ANS: Append

I picked extend and got the problem wrong because I mixed up the definition of extend with append. extend is for lists and append is for individual elements.

8) What does a WHILE loop do?

(a) Iterates over an iterable and for a set amount of time

(b) Intuitively takes an iterable and manipulates it over a set period using pointers

(c) Loop over a bound interval by comparing to a conditional

(d) Crash bitcoin

ANS: (C) I got this one wrong because I picked A initially. I forgot that the set amount of time part must be added in. C is the technical definition. A is how WHile loops work.

9) I want to iterate over a list until the user inputs 'quit'. What loop would I use?

(a) WHILE loops

(b) FOR loops

(c) Recursive Loops

(d) Paradoxical Loops

ANS: B, but I picked A because I was thinking of a while loop and a for loop. I understand why a for loop would be used.