Comptuer Studies Ruby Notes

These be nones I took charm I was discipline Ruby. Comptuer studies ruby nones Instance of a section is a sub-category of that class. E. g. greyhound dog. Every design has a class. designs are instances of classes. Methods define what an object gouge do and properties get it. Constants start with a capital letter, sometimes they are either caps e. g. sideline = 0. 012 telescope perpetual INTEREST to 1. 2% DOZEN = 12 setting constant DOZEN to 12 Constants and varyings store information in the storage for the duration of the drop of the political platform.Like RAM? Constants cant be budged further inconstants can be re specialiseed based on certain properties and data. Different types of classes partExample of Object Float6. 5 or 3. 9 Fixnum2 or 3 railroad trainThisisastring or randomnumber34 ArrayMonday Tuesday Wednesday atomic number 90 Friday Or January February March April HashToronto Dion Phaneuf Pittsburgh Sidney Crosby Washington Alex Ovechkin Or Haseeb November 18 Humza August 6 Hana August 11 Range11.. 20 Or Hi.. Ho Float = decimal number Fixnum/Integer = whole number String = letters and numbersArray = an ordered list, a couple of objects put together in adept list that can also be accessed independently cook a new array or reset an old one by using this array = Array. new You can also designate individual variables by doing arraynumber e. g. subjects3 you can also add objects to the array by subjects 4 = Social Science Hash = Similar to array but not in order, each object does not have a number. Its based on key and cheer pairs. Like if you put louvre names and assigned each a birthday. They would go based on those pairs. It assigns the first name to the second. E. g friends = Hash. ew friendsAndrea = July 22 friendsMohammed = April 9 Range = A range of values e. g. nums = 11.. 20 Setting variable Fav_food = pizza setting variable fav_food to pizza The quote marks around pizza identify that fav_food is a string value. Ide ntifiers are the constant/variables names In order to smorgasbord a variables value (not class) from one to an some other use the following To string x. to_s To float x. to_f To integer/fixnum x. to_i Keep in mind, this tho changes the variables value based on class properties, not its actual class Scope is where the variable can be accessed r seen within a program. Some are solely use for a small project while others may be utilise for larger tasks and appear several(prenominal) times within the program. Constants scope depends on how often it is stated. If a constant is only declared within a class or module its scope is within that scope or module. However if it is declared outside of that class or module its scope is wider or global. There four different variable scopes. Local variables are confined to the part of the program in which they are declared. If the variable is only declared within a method it is curb to when that method is used or executed.It cant be used anywhe re else in the program. (e. g. fav_food) Global variables can be declared anywhere in the program and are accessible from anywhere in the program. They are identified by a preceding $ e. g. $fav_food. Global variables, however have to be used with extreme caution due to the fact that their values can be changed anytime in the program, sometimes by accidental or careless coding, these accidents can cause huge problems and are not easily fixable. Class variables are confined to a specific class but once all instances of the class are created the value of the variable is shared amongst all instances.If the value is changed in one of the instances, it is changed in all of the instances. (e. g. fav_food) Instance variables are restricted to only certain instances of a class. If the value changes in one of the instances it stays the same in the others. (e. g. fav_food) Commands to determine classes Either puts variable. class or puts variable. kind_of? Class The first will tell you what class the variable is while the other will say true or false based on what class is inputted at the end of the line. Changing classes The easiest way is to just assign a new value to it.Another way is to use the to_s, to_i etc. commands while also using the = assignment operator in order to change the objects class permanently e. g. num = num. to_s you can do it without the = and the num variable before the equals sign in order to change it temporarily exclusively math operations are the same except for two. Modulo (%) Divides and gives the remainder and superpower is (**). E. g X = 6%4 X = 20 ** 2 There are also comparison operators such as puts a == b false as a and b are not equal puts a = b true as a and b are not equal puts a b returns true as b is larger puts a