Vocab

Binary:
- Bits
  - Bits are single pieces of information which can either have a 0 or a 1. They are the building block of all code.
- Bytes
  - A single byte is 8 bits. Megabytes, Gigabytes, etc are all multiples of bytes and they represent memory or storage
- Hexedecimal
  - base 16 counting. Binary is a base 2 system
- Unsigned Integer
  - An unsigned integer is a basic number value in bits. It does not include a negative or positive and therefore is non-negative
- Signed Integer
  - An integer with a negative or positive
- Floating Point
  - A way of approximately representing decimal values
- Boolean
  - Data type with a true/false value, can be represented with 1s and 0s
- ASCII
  - A Character encoding standard, transfers binary to chars
- Unicode
  - Another character encoding standard, builds on ASCII
- RGB
  - Color codes are represented in Hexidecimal which describe the red green and blue values to build a color EX: #FF0000, rgb(255, 0, 0)
Algorithm Terms:
- Variables: An abstraction inside a program that holds a specific value or meaning defined by the programmer.
- Data Types:
  - Integer- highScore (involves math, save as integer or numbers)
  - String- firstName (name is text, so it is a string)
  - Boolean- isSunny (2 options, true or false)
  - String- phoneNumber (no math, just numbers)
- Arithmetic Operators:
  - Plus indicated addition (a + b)
  - Minus indicates subtractions (a - b)
  - Asterisk indicated multiplication (a * b)
  - Slash indicated division (a / b)
- Managing Complexity:
  - Lists: Allows you to complete a process for each value in the list, or store multiple values to one variable.
  - 2D Lists: Array within an array. You can pull single arrays through using index and variable commands.
  - Dictionaries: Allows the storage or data keys and values (assigning a certain piece of data to fit the category it is assigned)
  - Class: A particular data structure.
  - Algorithms: An algorithm is a finite set of instructions that accomplish a specific task, us as humans, do algorithms on a daily basis.
  - Sequence: A specific order a process is completed, which impacts the output.
  - Selection: Programmer decides between 2 different functions
  - Iteration: Repetition of a process
  - For loop: repeats a section of code a set number of times
  - While loop: repearts a section of code an unknown number of times, until the code is told to break
  - Expressions: A piece of syntax in coding
- Characters:
  - Strings : A variable data type which consists of a combination of letters, numbers, and other special characters (ex: @#$%^&*). They are seen inside quotation marks, and operators cannot affect any numbers in the string.
    - Ex: stringVar = “Hello World!”
    - “Hello World!” is a string.
  - Length: The number of elements in a list. Here’s an example in Python:
    - numList = [1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 8 , 7 , 6 , 5 , 4 , 3 , 2 , 1]
  - Concatenation: the act of joining two strings into a single string. Often, these strings are printed to an output terminal/console. Here’s an example in pseudocode:
    - concat(“tri”, “llion”)
    - This concatenates the strings “tri” and “llion”, making a new string “trillion”.
  - Upper, Lower, Traversing Strings
    - The first two (upper and lower) seem to be referring to Python methods. They are quite simple. I think it would be easiest to explain with a demonstration:
    - String = “WhYaReWeDoInGtHiS”
    - print(string)
    - print(string.upper())
    - print(string.lower())
    - Output:
    - WhYaReWeDoInGtHiS
    - WHYAREWEDOINGTHIS
    - whyarewedoingthis

Variables, Assignments, Data Abstraction

Variables

Abstraction insde a program that can hold a value
Organizes data with a name
Consist of name, value, type
Understanding of code is through name of variables
Types of data:
- Interger, String, Boolean
- List can also be stored in variables
  - Print/retreive specific values
  - easily able to add and remove values

Assignments

Assignment operator allows program to change value represented by variable
- =, +=, -=, *=, /=, **=

Data Abstraction

Method used in coding to usefully represent data
Variables and list are primary tools
Provides seperation btw abstract properties of a data type and concrete details of its representation

Algorithms

Sequencing
- Algorithms do tasks in the order of specification.
Selection
- Helps choose two different outcomes based off a decision.
Iteration
- If a condition is true, then the code can repeat.
Flowcharts
- Use shapes and arrows to represent the steps of an algorithm.
Pseudocode
- A blend of human language and coding format.

Arithmetic Operation

Arithmetic operations exist in most programming languages.
subtraction (-)
addition (+)
multiplication (*)
division (/)
Getting the remainder (%)
ORDER OF OPERATIONS is crucial
- reassigning variables using operations on other variables can get confusing
PAY ATTENTION TO SEQUENCING SO OPERATIONS OF VARIABLES DONT GET MESSED UP
Track varaibles (common question in AP Exam)

String

A string is a collection of characters. What is a character as character can be anything from numbers, letters, spaces, special symbols, etc.
len () : to find the length of a string
lower () : to convert to lowercase
concat (): in pseudocode and varys from language to language can be used to combine to strings

Lists and Iteration

Lists

Sequence of variables
- Used to store multiple items in a variable
- ordered and flexibe
Tuple: collection thats ordered, unchangeable, allows duplicates
Set: Unordered, unchangeable, doesn't allow duplicates
Dictionary: ordered, changeable, doesn't allow duplicates
Index: refrences an element in a list that is in order
Elements: values in the list that are assigned to an index
Methods:
- append() adds elements
- index() returns the index of the first element with specificed value
- inset() adds element at given position
- remove() removes the first item with the specified value
- reverse() reverse list order
- sort() sorts the list
- count() returns amount of elements with specified value
- copy() returns a copy of the list
- clear() removes elements from list

Iteration

repetition of a process applied to the result or taken frmo previous statement
- for loops
- while loops
2 types of iteration: indefinite and definite
- definite: clarifies how many times the loop is going to run
- indefinite: how many times its going be ran based on conditions
When object is iterable it can be used in an interation
Iter() returns an interator
Strings, list, dictionaries, sets, and tuples are iterable objects
Break: stops the loop

2D Iteration

Lists of lists
Read in 2 dimensions (list on top of list

Algorithms and Conditionals vs Booleans and Binary Search/Flowcharts

Algorithms

Process or set of rules to be followed through code
- Set limitations
Algorithms can be written in different ways and still accomplish the same tasks
Algorithms that appear similar can yield different side effects or results.
Some conditional statements can be written as the same as Boolean expressions (VICE VERSA)
Different algorithms can be developed or use to solve the same problem. ## Conditional vs Booleans
Boolean expression when an expression outputs true or false
Booleans can only hold true or false ## Flowcharts
Help you visualize functonality of an algorithm
Good way to double check whether an algorithm is acheiving its purpose ## Binary Search
Search algorithm that finds position of target value within a sorted array
- Algorithm for iteratin gto find a value inside a data set
Starts in middle of data set and eliminates half the data
COLLEGE BOARD INDEX STARTS AT 1 NOT 0 ## Libraries
A library is a collection of precompiled codes that can be used later on in a program for some specific well-defined operations.
These precompiled codes can be referred to as modules. Each module contains bundles of code that can be used repeatedly in different programs.
A library may also contain documentation, configuration data, message templates, classes, and values, etc.
Importance:
- Using Libraries makes Python Programming simpler and convenient for the programmer.
- One example would be through looping and iteration, as we don’t need to write the same code again and again for different programs.
- Python libraries play a very vital role in fields of Machine Learning, Data Science, Data Visualization, etc. ## APIS
An Application Program Interface, or API, contains specific direction for how the procedures in a library behave and can be used.
An API acts as a gateway for the imported procedures from a library to interact with the rest of your code.

Examples

List Example:

colorsList=["pink", "yellow", "green", "blue", "orange"]

print(colorsList)

['pink', 'yellow', 'green', 'blue', 'orange']

Variable type examples (string,integer,boolean):

name = "table1" #string
print(name, type(name))

number = 4 #integer
print(number, type(number))

isAbsent = False
print(isAbsent, type(isAbsent))

table1 <class 'str'>
4 <class 'int'>
False <class 'bool'>

Operators Examples:

num1 = 2 - 1
num2 = 2 + 1
num3 = 2 * 1
num4 = 2 / 1
num5 = 5%2
print(num1)
print(num2)
print(num3)
print(num4)
print(num5)

1
3
2
2.0
1

Algorithm Examples

Algorithms with same code but differnt results

temp = int(input("Select a temperature from 0 to 99 degrees F"))
if (temp >= 90):
    print("It's too hot outside!")
else:
    if (temp >= 65):
        print("Sure I will play outside!")
    else: 
        print("It is too cold outside!")
# Input 54 and then 95, what do you notice?

It's too hot outside!

temp = int(input("Select a temperature from 0 to 99 degrees F"))
if (temp >= 90):
    print("It's too hot outside!")
if (temp >= 65):
    print("Sure I will play outside!")
if (temp < 65):
    print("It is too cold outside!")
    # Input 54 and then Input 95, what do you notice?

It's too hot outside!
Sure I will play outside!

Algorithms that accomplish the same task but differnet code

sum = 1
counter = 3
#iteration
var = 0 
while (var < 4): #while the var is <= 4, it executes those commands, once it exceeds it hits the else command
    sum = sum + counter
    counter = counter + 2
    var = var + 1
    # now go through the whole thing 4 times, this is an iteration, a vital part of algorithms.
else:
    print(sum)

sum = 0
counter = 9
#iteration
while (counter >= 1): 
    sum = sum + counter
    counter = counter - 2
print(sum)

Building an Algorithm Steps:

print("choose value for x")

varx=int(input("Enter any positive Integer"))

if (varx %2 == 0):
     varx == varx/2       # Change print to the function

else:
    varx == varx * 3 + 1      # Change print to the function

print(varx)

print("choose value for x")

varx=int(input("Enter any positive Integer"))

while varx != 1:

    if (varx %2 == 0):
        varx = varx/2       # Change print to the function

    else:
        varx = varx * 3 + 1      # Change print to the function

print(varx)

print("choose value for x")

varx=int(input("Enter any positive Integer"))

print(varx)
while varx != 1:

    if (varx %2 == 0):
        varx = varx/2       
        print(varx)               # add Display
    else:
        varx = varx * 3 + 1      
        print(varx)               # add Display
print(varx)                       # Final # Should be 1 every time

Binary Search Example:

def BinarySearch(array, x, low, high):

    # Repeat until the pointers low and high meet each other 
    while low <= high:

        mid = low + (high - low)//2 # find the middle (taking the higest index number plus the lowest and divided by two)

        if array[mid] == x: # if desired number is the middle is found return desired number (middle number) 
            return mid

        elif array[mid] < x: 
            low = mid + 1

        else:
            high = mid - 1

    return -1


array = [3, 4, 5, 6, 7, 8, 9]
x = 4

result = BinarySearch(array, x, 0, len(array)-1)

if result != -1:
    print("Element is present at index " + str(result))
else:
    print("Not found")

Element is present at index 1