Notes on Units 3.3 & 3.4

Algorithms

  • Sequencing
    • helps tasks function in order (Example: PEMDAS)
  • Selection
    • chooses one of two different outcomes from one decision (Example:)
  • Iteration
    • if a condition is true, then it can repeat starting from a certain step until the condition is false (Example: While Loop)
  • Flowcharts
    • show how the algorithm works (Helps visualize the way the code works)

Arithmetic Operation

  • subtraction (-)
  • addition (+)
  • multiplication (*)
  • division (/)
  • Getting the remainder (MOD) (%)
  • ORDER OF OPERATIONS MATTERS
    • reassigning variables using operations on other variables can get confusing

Arithmetic Hacks 

Num1 = 50
Num2 = Num1 % 9 + 15                    # num2 = 20
Num3 = Num2 / Num1 + ( Num2 * 2 )       # num3 = 20/50 + 40 = 40.4
Num4 = Num3 + Num1 / 5 - 10             # num4 = 40.4 + 10 - 10 = 40.4
Result = Num4 - Num2                    # Result = 40.4 - 20 = 20.4

Num1 = 10
Num2 = Num1 % 3 * 4                     # num2 = 1 * 4 = 4
Num1 = Num2                             # num1 = 4
Num3 = Num1 * 3                         # num3 = 4 * 3 = 12
Result = Num3 % 2                       # Result = 0

valueA = 4
valueB = 90
valueC = 17
valueB = valueC - valueA                # valueB = 17 - 4 = 13
valueA = valueA * 10                    # valueA = 4 * 10 = 40
if valueB > 10:                         # valueB is 13, which is greater than 10
    print(valueC)                       # This will print 17

type = "curly"
color = "brown"
length = "short"                        
type = "straight"                       
hair = type + color + length            # hair = curly + brown + short
print(hair)                             # This will print curlybrownshort

17
straightbrownshort

Strings

  • Collection of character (#s, letters, spaces, special characters)
  • procedures can be used with strings
    • len() finds length of strings
  • concatenation combines strings
    • concat("cookie", "monster") outputs "cookiemonster"

Problem 1 

Noun = "Mr.Mortenson" 
Adjective = "handsome" 
Adjective2 = "Very" 
Verb = "is" 
abrev = Noun[0:7]
yoda = Adjective2 + " " + Adjective + " " + abrev + " " + Verb + "."
print(yoda)

Very handsome Mr.Mort is.

Problem 2 

cookie = "chocolate" 
cookie2 = "raisin" 
len1 = (len(cookie) / 2)
len2 = (len(cookie2) * 45)
vote1 = (cookie + " vote " + str(len2))
vote2 = (cookie2 + " vote " + str(len1))
print(vote1 +  "\n" + vote2)

chocolate vote 270
raisin vote 4.5