python chapter 1

Comments

'#' characters denote comments, which are optional but can be used to explain portions of code to a human reader.

bits

0s and 1s are known as bits (binary digits).

bits

A byte is 8 bits

program

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

disk

A disk (aka hard drive) stores files and other data, such as program files, song/movie files, or office documents.

keyboard

A keyboard allows a user to provide input to the computer.

bug

A logic error is often called a bug.

memory

A memory is a circuit that can store 0s and 1s in each of a series of thousands of addressed locations

interactive interpreter

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

whitespace

Any space, tab, or newline is called whitespace.

scripting languages

As computing evolved throughout the 1960s and 1970s, programmers began creating scripting languages to execute programs without the need for compilation

assembly

Because 0s and 1s are hard to comprehend, programmers soon created programs called assemblers to automatically translate human readable instructions, such as "Mul 97, #9, 98", known as assembly language instructions, into machine instructions.

integrated development environment

Code development is usually done with an integrated development environment, or IDE

IDE

Code development is usually done with an integrated development environment, or IDE.

code

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

newline

Each print statement will output on a new line. A new output line starts after each print statement, called a newline.

IC

Engineers created smaller switches called transistors, which in 1958 were integrated onto a single chip called an integrated circuit or IC.

integrated circuit

Engineers created smaller switches called transistors, which in 1958 were integrated onto a single chip called an integrated circuit or IC.

transistors

Engineers created smaller switches called transistors, which in 1958 were integrated onto a single chip called an integrated circuit or IC.

expressions

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

int()

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

high-level languages

In the 1960s and 1970s, programmers created high-level languages to support programming using formulas or algorithms.

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.

Phyton

In the late 1980s, Guido van Rossum began creating a scripting language called Python and an accompanying interpreter.

machine instructions

Instructions represented as 0s and 1s are known as machine instructions

Moore's Law

Moore's Law: The doubling of IC capacity roughly every 18 months, which continues today.

syntax error

One kind of mistake, known as a syntax error, is to violate a programming language's rules on how symbols can be combined to create a program

newline character

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

print()

Print() displays variables or expression values.

variables

Programs use variables to refer to data, like x.

backwards compatible

Python 2.7 programs cannot run on Python 3.0 or later interpreters, i.e., Python 3.0 is not backwards compatible.

open-source

Python is an open-source language, meaning the community of users participate in defining the language and creating new interpreters, and is supported by a large community of programmers.

RAM

RAM (random-access memory) temporarily holds data read from storage, and is designed such that any address can be accessed much faster than disk, in just a few clock ticks (see below) rather than hundreds of ticks.

print()

Reading input is achieved using the input() function.

logic error

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

string literal

Text enclosed in quotes is known as a string literal.

Python interpreter

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

Python standard library

The Python standard library includes various utilities and tools for performing common program behaviors.

string

The input obtained by input() is any text that a user typed, including numbers, letters, or special characters like # or @. Such text in a computer program is called a string, and is always surrounded by single or double quotes, for example 'Hello' or "#Goodbye# Amigo!"

prompt

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

Variables

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

operation system

The operating system allows a user to run other programs and which interfaces with the many other peripherals.

print()

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

processor

The processor runs the computer's programs, reading and executing instructions from memory, performing operations, and reading/writing data from/to memory.

runtime error

The program may have another kind of error called a runtime error, wherein 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').

app

The programmer-created sequence of instructions is called a program, application, or just app.

application

The programmer-created sequence of instructions is called a program, application, or just app.

program

The programmer-created sequence of instructions is called a program, application, or just app.

line

a line is a row of text

assigment

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

cache

A processor may contain a small amount of RAM on its own chip, called cache memory, accessible in one clock tick rather than several, for maintaining a copy of the most-used instructions/data.

clock

A processor's instructions execute at a rate governed by the processor's clock, which ticks at a specific frequency

Input

A program gets data, perhaps from a file, keyboard, touchscreen, network, etc.

process

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

output

A program puts that data somewhere, such as to a file, screen, network, etc.

screen

A screen (or monitor) displays items to a user.

interpreter

A script is a program whose instructions are executed by another program called an interpreter.

script

A script is a program whose instructions are executed by another program called an interpreter.

Algorithm

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

executable program

A sequence of machine instructions together form an executable program (sometimes just called an executable).

statement

A statement is a program instruction.

crash

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

instruction

To support different calculations, circuits called processors were created to process (aka execute) a list of desired calculations, each calculation called instruction.

processors

To support different calculations, circuits called processors were created to process (aka execute) a list of desired calculations, each calculation called instruction.

Compilers

To support high-level languages, programmers created compilers, which are programs that automatically translate high-level language programs into executable programs.