Zybooks Chapter 2

Variable

A name item, such as x or num_people, used to hold a value

Assignment Statement

Assigns a variable with a value, such as x = 5. Left side must be a variable, the right side can be an expression. Assigns the variable on the left-side of the = with the current value of the right-side expression.

Incrementing

Increasing a variable's value

Identifier

Also called a name, a sequence of letters (a-z, A-Z), underscore(_), and digits (0-9), and must start with a letter or an underscore.

Case Sensitive

Meaning upper- and lowercase letters differ.

Reserved Words/Keywords

Words that are part of the language, and thus, cannot be used as a programmer-defined name.

Bits

A single 0 or 1

Byte

Eight bits, like 11000101

Character

A letter, symbol, or single digit number.

ASCII

Stands for American Standard Code for Information Interchange. A popular code for characters developed in 1963. Uses 7 bits per code, and has codes for 95 characters.

Unicode

Character encoding standard, whose codes can have more bits than ASCII and thus can represent over 100,000 items, such as symbols and non-English characters.

Integer

Can hold whole number values, like 1, 999, 0, -25.

Floating-point number

A real number, like 98.6, 0.0001, or -666.667. Refers to the decimal point being able to appear anywhere ("float") in the number.

Floating-point literal

Written with the fractional part even if that fraction is 0, as in 1.0, 0.0, or 99.0

Scientific Notation

Written using an e preceding the power-of-10 exponent, as in 6.02e23 to represent 6.02x10^23. The e stands for exponent.

OverflowError

Occurs when a value is too large to be stored in the memory allocated by the interpreter.

Raw string

Can be created by adding an 'r' before a string literal.

ord()

Returns an encoded integer value for a string of length one.

chr()

Returns a string of one character for an encoded integer.

Expression

A combination of items, like variables, literals, operators, and parentheses, that evaluates to a value, like 2 * (x + 1).

Literal

Specific value in code like 2.

Operator

a symbol that performs a built-in calculation, like +, which performs addition.

Unary Minus

Minus (-) used as negative.

Compound operators

Provide a shorthand way to update a variable, such as age += 1 being shorthand for age = age + 1. Other compound operators include -=, *=, /=, and %=

Module Operator (%)

Evaluates the remainder of the division of two integer operands.

Division (/): Integer rounding

The division operator / performs division and returns a floating-point number.

Floor Division (//)

Used to round down the result of a floating-point division to the closest smaller whole number value. The resulting value is an integer type if both operands are integers; if either operands is a float, then a float is returned.