NEW - Cheat Sheets
From Today’s newsletter:
5/11/2020 Learn SQL: Queries Cheatsheet Codecademy 2/4 SELECT Statement The SELECT. statement returns all columns from the provided table in the result set. The given query will fetch all columns and records (rows) from the movies table. Wildcard The wildcard can be used in a LIKE operator pattern to match any single unspecified character. University of the Fraser Valley.
Growing up, we had to memorize the spelling of words like “return,” remember that 12 x 12 = 144, and recall the conjugations of tener . Coding is not so different, having to memorize specific syntax, rules, and commands. And in coding, you’ll get an error if you misspell return , so it’s important to remember the details.
But coding should be less about rote memorization and more about understanding the principles at work. So to help you focus more on deeper understanding, we created Codecademy Cheat Sheets.
You can refer to a Cheat Sheet when you’re building your next project or querying a new data set. We also made them downloadable as PDFs, so you can take them with you anywhere.
We currently have cheat sheets for the following courses:
More to come in the future. You’ll find them at the end of each relevant lesson.
- Java Cheat Sheet
This cheat sheet summarizes common parts of the syntax of the Java programming language. It also provides techniques for handling common procedures. This sheet is not a complete overview.
Basics
Common terms
| variable | piece of data that can hold a value |
| object | represents something in real world |
| class | definition of an object (like a blueprint or recipe) |
| attribute | variable, part of a class, also called: field, member- or instance variable |
| method | set of statements (code), part of a class |
Hello World
Built-in types
| Type | Example values | Common operators |
|---|---|---|
| int | 3, 400, -200, 0 | + - / * % |
| boolean | true false | && || ! |
| char | 'a' '3', '/', '%' | |
| String | 'Hello' 'world peace' '3.5' | + |
int, boolean, char are primitive types, String is a class.
Variables and Types
Declare
Declare & assign value
Type is an object
Class
Definition
Object
Declare an object p of type Person:
Declare & initialize
Codecademy Cheat Sheet Javascript
Object p becomes a new Person:
Object p is an instance of the class Person.
Method
Definition: class with two methods
Writing style
class names start with a capital letter;
indent-code blocks;
Code structure
source file (.java)
class
statement;
statement;
What goes in a source file?
What goes in a class?
What goes in a method?
Conditions
Booleans
Boolean expression
If
Codecademy Cheat Sheet
Boolean as result of method
Boolean operators
Expressions
Basic
Operators
Call (=use) methods
Call method save() of object context
Method returns a value
More info
Learn more at:
Alternative cheatsheets
API
An API is a description of a library. A library is a set of classes (also called: package) to add to your program.
Sequel Command Cheat Sheet
Import
Codecademy Html Cheat Sheet
Put import statements at the top of your code. Use class ArrayList from package java.util:
Comments are closed.