ap computer science principles

• Compress = To decrease the number of bits used to represent a piece of information
• Data compression = Involves encoding information using fewer bits than the original representation
• Image = A type of data used for graphics or pictures
• Lossless = A compression scheme in which every bit of the original data can be recovered from the compressed file
• Lossy = A compression scheme in which "useless" or less-than-totally-necessary information is thrown out in order to reduce the size of the data. The eliminated data is unrecoverable
• Metadata = Is data that describes other data. For example, a digital image might include metadata that describe the size of the image, number of colors, or resolution.
• Raw data = The original data as it was collected without any modification, compression, etc.
• Visualization = Images, diagrams, tables, etc. created from information extracted from a given data set, with the express intention of highlighting a data story.
• ! = "not" logical operator
• #000000 = Black represented RGB in 32Bit Hex
• #0000FF = Blue represented RGB in 32Bit Hex
• #00FF00 = Green represented RGB in 32Bit Hex
• #FF0000 = Red represented RGB in 32Bit Hex
• #FFFFFF = White represented RGB in 32Bit Hex
• && = "and" logical operator
• || = "or" logical operator
• == = Equality operator; used to compare two values, and returns a Boolean (true/false). Avoid confusion with the assignment operator "=",
• Abstraction = Reducing information and detail to focus on essential characteristics.
• Algorithm = A sequential set of steps or process for solving a problem.
• American Standard Code for Information Interchange (ASCII) = The most common format for text files in computers and on the Internet. In this standard, each alphabetic, numeric, or special character is represented with a 7-bit binary number (a string of seven 0s or 1s). 128 possible characters are defined.
• API (Application Programming Interface) = A collection of commands that can be used in a programming language to carry out a variety of processes. These commands are the "interface" that the programmer will use to build applications in that language.
• Array = A synonym for a List
• Binary Code = Representation of computer processor instructions using any two-symbol system, but often the numbers 0 and 1.  Machine Language is written in this.
• Binary Question = A question to which there are only two possible answers
• Boolean = An expression is any expression that can only evaluate to either TRUE or FALSE.
• Byte = 8 bits
• Calling a function = Telling the computer to run (or execute) that set of actions.
• Computationally hard = A problem for which there is no proven algorithm for solving in a reasonable time
• Concatenate = To link together or join – used to join strings together in Python
• Megabyte (MB) = 1,024 Kilobytes (KB)
• Modulo (or "mod") = The name of the mathematical operation that gives the REMAINDER from dividing one number by another
• Octal = The octal number system is base 8, using only digits 0 through 7.
• One-way function =  a process that is easy to “DO”, but difficult to “UNDO”
• Overflow = error that results when the number of bits is not enough to hold the number, like a car's odometer "rolling over"
• Parameters = Arguments passed to a function.  Variable values that control options for how some code runs.  (think of turning various knobs to control a device)
• Petabyte (PB) = 1,024 Terabytes (TB)
• Pixel = short for "picture element" it is the fundamental unit of a digital image, typically a tiny square or dot which contains a single point of color of a larger image
• Return Value

  A value that is passed back when a function returns to the place in the code where the function was called
• RGB

  A color model that uses varying intensities of (R)ed, (G)reen, and (B)lue light are added together in to reproduce a broad array of colors.
• Round-off

  Error that results when the number of bits is not enough to represent the actual number, like 3 digits to represent π as 3.14