Hack Grades

lesson 9-11: 0.97/1 lesson 12-13: 0.9/1 lesson 14-15: 0.9/1

total: 0.97 + 0.9 + 0.9 = 2.77/3

Lesson Vocabulary Linked below:

click here

Unit 3 Sections 12-13 Notes

Procedures

  • A procedure is a named set of instructions that can take in parameters and return values.
    • May be called "method" or "function" in different programming languages.
  • Parameters are independent variables used in the procedure to produce a result.
    • allows a procedure to execute without initially knowing specific input values.
    • calling a procedure = write the name of the procedure followed by the parentheses with the parameters of the procedure

Example:

x = 5
y = 3

def multiply(x, y):  # (x,y) is a parameter
    product = x * y
    return product

answer = multiply(x, y) # this is the procedure being called
print("The product of", x, "times", y, "is", answer)

Determining Procedure Results

  • To determine the result = follow the code line by line and see what each one does
    • look at: function parameters, return values, and statements
    • return values = write the syntax return followed by the expression you would like to return
    • A return statement exits a function and instructs python to continue executing the program and to return a certain value

Example:

def divide(num1,num2):
      x = num1/num2
      return x # return value returns value of variable x

Managing Complexity

Vocab:

  • Modularity - the practice of breaking a complex program into smaller, independent parts or modules that can be used and reused in different parts of the program
  • Abstraction - the practice of hiding the details of how a particular code or system works and exposing only the essential features or functions that are necessary for other parts of the program to use
  • Duplication - having multiple duplicate code blocks, often decreasing readability and efficiency
  • Logic - the sequence of steps and operations that a computer follows to execute a program, including the specific instructions and decision-making processes built into the code

Modularity and Abstraction example form hack (avoids duplication): 

questionnumber = 3
meals = []
questions = [
    "What did you eat for breakfast? Bacon, eggs, or cereal?",
    "What did you eat for lunch? A sandwich, mac and cheese, or a lunchable?",
    "What did you eat for dinner? Pizza, pasta, or a salad?"
]

def mealask(question):
    print("Question: ", question)
    response = input()
    print("Your response: ", response)
    meals.append(response)

for number in range(questionnumber):
    mealask(questions[number])

for i in meals:
    if i == "cereal" or i == "lunchable" or i == "pizza":
        print(i, " was not a healthy choice")
    elif i == "bacon" or i == "mac and cheese" or i == "pasta":
        print(i, " was not a bad choice")
    else:
        print(i, " was a healthy choice")

Developing Procedures

  • Procedure - a module of code that is created to complete a certain task, this is basically a function
  • Procedure Name - the name that is given to a function/procedure -Parameters - a variable that is used in a function to allow for data to be imported into a function -Arguments - a way to provide information to a function, usually defined outside a function and then imported into a function with parameters

below is the basic formatting for procedures in python:

def function(a,b): # function is defined
  print(a+b) # prints output of variables

function(1,2) # one instance that it can be used
function(2,3) # another instance

below is the basic formatting for procedures in javascript:

function Newfunction(a,b) {
  return a + b;
}

Function(1,2)
Function(2,3)

Calling Functions in HTML

  • Use javascript
  • define your funtion
  • call your function with a button and onclick

Example:

<!-- function is called here -->
<button id="enter" onclick="print(a,b)">HI</button> 
<p id="result"></p>
<!-- javascript -->
<script>
    function print(a,b) {
        document.getElementById("result").innerHTML = a + b // math
    }
    // variables are defined
    var a = 1
    var b = 2
</script>

Unit 3 Sections 14-15 Notes

College Board Essential Knowledge

  • A software library contains procedures that can be used in the creation of new programs = a collection of code from an external source that can be used to add functionality to a program.
  • Existing segments of code can come from internal or external sources, ie. libraries or previously written code (ex. the random.randint from random)
  • libraries simplify the task of creating complex programs (code already written)

  • Application program interfaces (APIs) are specifications for how the procedures in a library behave and can be used.

  • Randomization generates a value between two numbers

Example of libraries and randomization:

import random #random library

#This is a magic globe that will predict how many toys you will get this winter

print("How many toys will you get this Christmas?")
randomnumber = random.randint(0,100)

print("You will get ", randomnumber, " toys this Christmas")

The Different Methods of the Random Function (in random library)

< mark> Method | Description </mark>

seed() | Initialize the random number generator

getstate() | Returns the current internal state of the random number generator

setstate() | Restores the internal state of the random number generator

getrandbits() | Returns a number representing the random bits

randrange() | Returns a random number between the given range

randint() | Returns a random number between the given range

choice() | Returns a random element from the given sequence

choices() | Returns a list with a random selection from the given sequence

shuffle() | Takes a sequence and returns the sequence in a random order

sample() | Returns a given sample of a sequence

random() | Returns a random float number between 0 and 1

uniform() | Returns a random float number between two given parameters

betavariate() | Returns a random float number between 0 and 1 based on the Beta distribution (used in statistics)

expovariate() | Returns a random float number based on the Exponential distribution (used in statistics)

gammavariate() | Returns a random float number based on the Gamma distribution (used in statistics)

gauss() | Returns a random float number based on the Gaussian distribution (used in probability theories)

lognormvariate() | Returns a random float number based on a log-normal distribution (used in probability theories)

normalvariate() | Returns a random float number based on the normal distribution (used in probability theories)

vonmisesvariate() | Returns a random float number based on the von Mises distribution (used in directional statistics)

paretovariate() | Returns a random float number based on the Pareto distribution (used in probability theories)

weibullvariate() | Returns a random float number based on the Weibull distribution (used in statistics)

Below is an example of a situation you would need the random function (a colored spinner): 

import random

colorspinner =  random.randint(1,8)

if colorspinner <= 3:
    print("green")
elif colorspinner <= 5:
    print("blue")
elif colorspinner <= 6:
    print("purple")
elif colorspinner <= 7:
    print("red")
else:
    print("orange")

Lesson Unit 3 Section 16 Notes:

This is our lesson: refer to this presentation for notes and guidance

Unit 3 Sections 17-18 Notes

  • Collatz= conjecture that is one of the most famous unsolved problems in mathematics. The conjecture asks whether repeating two simple arithmetic operations will eventually transform every positive integer into 1.

  • Hailstone numbers= The sequence of integers generated by Collatz conjecture are called Hailstone Numbers. Examples:Input : N = 7 Output : Hailstone Numbers: 7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1 No.> ### Iteration The action or a process of iterating or repeating:such as. : a procedure in which repetition of a sequence of operations yields results successively closer to a desired result.

  • Undecidable problems= An undecidable problem is one that should give a "yes" or "no" answer, but yet no algorithm exists that can answer correctly on all inputs.

  • Unsolvable problems= An unsolvable problem is one for which no algorithm can ever be written to find the solution.

sequence = []

def combinedcollatz(i):
    while i > 1:
        if (i % 2):    # i is odd
            sequence.append(i)
            i = 3*i + 1
        else:   # i is even
            sequence.append(i)
            i = i//2
    if i == 1:
        sequence.append(1)
    else:
        print(i, "is invalid, please try again") #this will print if the number is invalid

 
 
i = int(input('Enter i: '))
combinedcollatz(i)
print("Hailstone numbers: ", sequence, "\nNumber of iterations: ", len(sequence)-1)

Hailstone numbers:  [12, 6, 3, 10, 5, 16, 8, 4, 2, 1] 
Number of iterations:  9

Efficient vs. Inefficient Algorithims Examples

  • Algorithmic efficiency is an aspect of algorithmic programming that measures the number of steps needed to solve a problem
class_to_do = []
i = 0
while i == 0:
    task = input("What assignment do you have to do today?")
    if task == "nothing":
        i = i + 1
    else:
        class_to_do.append(task)

print("Tasks you have to do today: ", class_to_do)

taskone = input("What assignment do you have to do today?")
print("You have to do", taskone)

tasktwo = input("What's another assignment you have to do today?")
print("You have to do", tasktwo)

taskthree = input("What's another assignment you have to do today?")
print("You have to do", taskthree)

taskfour = input("What's another assignment you have to do today?")
print("You have to do", taskfour)