3.1 Variables and Assignments

Variables are specific things that stores a value
Values can be individual datas or a list/collection that contains many data values
Types of data include ints, Booleans, lists, and strings
- Floats work just like ints, but floats have decimals
Assignments is done with the = sign
- Lists are assigned withcan have values added to them with the append function
- Dictionaries are initialized with {} and : signs
- variables can also be assigned
Expressions can be used to change a number +,-,*,/,//,% are some of the examples

3.2 Data Abstraction

Connects the abstract data with concrete details of its representation
Manage Complexity by refering to a variable without assigning it to a name
- Lists can treat many variables by treating it like a single variable.
Data abstraction makes it easier to maintain code
Collegeboard lists starts at 1, instead of 0 like most programming languages
The split function can be used to split a string into a list

Functions like a list of chars, with indexes at each char of itself.
Concatenaction is the addition of a string to another, with the + expression
Length is the number of chars in a string
A substring is a part of a string
Psuedocode is a procedure that is not written in actual code, but is easiliy understandable

Boolean Expression reads off operands at its two sides and returns a boolean result
- Consists of Relational and Logical Operators
Relational Operators consists of ==, !=, <, >, <=, >=
Logical Operators' operands is only booleans and consists of not, and, or
In evaluation, Relational Operator goes first, then not, and, or, in that order

Conditionals decides the flow of the algorithm depending on a boolean
If the boolean is true, it goes to the if clause, else, it goes to the else clause
Conditionals are good to construct algorithms
Nested Conditionals are if-else clauses in side a if-else clause and helps algorithms further

Iteration is the repetition of a particular set of algorithm
- Conditional Iteration is iterations that only stops when a condition is met, often using if statements
Iteration is often done using loops
- Also often uses lists or dictionaries
Nested loops is useful for iterating inside a iteration

Algorithm is a set of procedure that can be followed to solve a problem
A problem can have many algorithms that solves it
When looking at a program, it is important to understand the algorithm used to control it
- An algorithm can have flow control controlled by if-else statements
Understanding what parameters should go in is necessary

Lists are a number of items that is refered to by an index
- In most languages, the index start at 0 (but it starts at 1 for collegeboard)
Lists can be used to store a large amounts of information that would've required a lot of variables to store
Methods can be used on lists to modify what the list is made of as well as access specific values

Searching is a way for the computer to find the location of a value
Searching each value in succession is not optimal
Having the list being sorted from least to great can enable binary search
- Binary search is more optimal than searching each one in succession, having log complexity than linear complexity
  - Divide the list in 2 parts at each step, so no need to look over every value

Procedure is a named method of code that takes input and returns output
- Basically same as function
Parameter is the values that a procedure takes in
Arguments are things specifying the values of parameter

Need to know things in order to create a procedure
- The type, value, and meaning of the input
- The intended output and how to arrive at the output
Modularity is the seperating of parts into functions to simplify things
Procedral Abstraction is calling a procedure without actually stating what a
- Basically the ability to function calls
A return statement ends a procedure and returns a value
- Done with the return keyword in most languages

Libraries are preexisting sets of functions that have to be imported to be used
In python, libraries are imported with the import keyword
- math is a python library that has functions that helps with maths, like square roots and trignometry
- turtle is another library that can draw things on a canvas

Randomness in programming is done with a random number generator, or the RNG gamers often talks about
random is the python library for randomness, it has several useful functions to generate random values
- random.random() generates a random float between 0 and 1
- random.randint() generates a random int between its two parameters, inclusice
- random.shuffle() randomizes the order of a list
Randomness is often used to simulate real world scenerios that is random
- Example: a die roll

Simulation is a program that simulates a simpler version of a real-world event
Can change things without real world concerns, i.e "Let's reduce the population by 1/2"
Often simplify things to make simulating easier
- Can cause bias without meaning to because of accidental exclusion of a variable that changes the outcome in real life
RNG often used to create randomness

Problem is a task that may or may not be solvable with an algorithm
- Decision Problems gives a yes or no answer
- Organisation Problems seeks to find the best answer
Instance is a set of specific inputs of a problem
Efficiency is how fast the program can run, or the amount of computing that needs to be done to solve the problem
- Most of the time we want a program to increase efficiency linearly or less when we have more inputs
Heuristic Approach is the approach that sacrafices the optimal solution for more efficiency

Undecidable problems are problems that have no solution
- Can result from a paradox
- Can cause a time out of a website due to the internet being stuck in a paradox that is not fixed