Chapter 1 : ZyBooks Python Vocab

program

A computer program consists of instructions executing one at a time.

Input

Input: A program receives data from a file, keyboard, touchscreen, network, etc.

Process

Process: A program performs computations on that data, such as adding two values like x + y.

Output

Output: A program puts that data somewhere, such as a file, screen, or network.

variables

Programs use variables to refer to data, like x.

computational thinking

In the information age, many people believe computational thinking, or creating a sequence of instructions to solve a problem, will become increasingly important for work and everyday life.

algorithm

A sequence of instructions that solves a problem is called an algorithm.

Python interpreter

The Python interpreter is a computer program that executes code written in the Python programming language.

interactive interpreter

An interactive interpreter is a program that allows the user to execute one line of code at a time.

Code

Code is a common word for the textual representation of a program (and hence programming is also called coding).

line

A line is a row of text.

prompt

The interactive interpreter displays a prompt (">>>") that indicates the interpreter is ready to accept code.

statement

A statement is a program instruction.

Expressions

Expressions are code that return a value when evaluated; for example, the code wage hours weeks is an expression that computes a number.

variables

The names wage, hours, weeks, and salary are variables, which are named references to values stored by the interpreter.

assignment

A new variable is created by performing an assignment using the = symbol.

print()

Print() function displays variables or expression values.

comments

Characters such as "#" denote comments, which are optional but can be used to explain portions of code to a human reader.

print()

The primary way to print output is to use the built-in function print().

string literal

Text enclosed in quotes is known as a string literal.

newline

A line break, known as a newline, is output after every print() statement.

newline character

Output can be moved to the next line by printing "\n", known as a newline character.

whitespace

Any space, tab, or newline is called whitespace.

input()

Reading input is achieved using the input() function.

string

The input obtained by input() is any text that a user typed, including numbers, letters, or special characters such as # or @. Such text in a computer program is called a string.

type

Strings and integers are each an example of a type; a type determines how a value can behave.

int()

If a string contains only numbers, like '123', then the int() function can be used to convert that string to the integer 123.

whitespace

Whitespace is any blank space or newline.

variable

In a program, a variable is a named item, such as x or num_people, that holds a value.

assignment statement

An assignment statement assigns a variable with a value, such as x = 5.

incrementing

Increasing a variable's value by 1, as in x = x + 1, is common and known as incrementing the variable.

identifier / name / underscores

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

case sensitive

Python is case sensitive, meaning uppercase and lowercase letters differ. Ex: "Cat" and "cat" are different.

Reserved words / keywords

Reserved words, or keywords, are words that are part of the language and cannot be used as a programmer-defined name.

PEP 8

PEP 8 (Python Enhancement Proposal) outlines the basics of how to write Python code neatly and consistently.

object

An object represents a value and is automatically created by the interpreter when executing a line of code. For example, executing x = 4 creates a new object to represent the value 4.

garbage collection

Deleting unused objects is an automatic process called garbage collection that frees memory space.

Name binding

Name binding is the process of associating names with interpreter objects. An object can have more than one name bound to it, and every name is always bound to exactly one object. Name binding occurs whenever an assignment statement is executed, as demonstrated below.

Value

Value: A value such as "20", "abcdef", or "55".

Type

Type: The type of the object, such as integer or string.

Identity

Identity: A unique identifier that describes the object.

type()

The built-in function type() returns the type of an object.

Mutability

Mutability indicates whether the object's value is allowed to be changed.

immutable

Integers and strings are immutable; meaning integer and string values cannot be changed.

id()

Python provides a built-in function id() that gives the value of an object's identity.

syntax error

One kind of mistake, a syntax error, violates a programming language's rules on how symbols can be combined to create a program.

runtime error

The program may have another kind of error called a runtime error, in which a program's syntax is correct but the program attempts an impossible operation, such as dividing by zero or multiplying strings together (like 'Hello' * 'ABC').

crash

Abrupt and unintended termination of a program is often called a crash of the program.

logic error

Such an error is known as a logic error, because the program is logically flawed.

bug

A logic error is often called a bug.