Day of 1 of learning Swift

November 29, 2022

I recently found a site called hackingwithswift.com and I have decided to try it as I have always wanted to learn how to code. Although, I have been doing a lot of scripting with BASH, I feel that my road to be an actual developer requires learning something beyond shell scripting.

The author of the site recommends that i spend an hour of coding a day so that I can better at developing using swift. So for the past hour I have read and typed the code example the site has for creating variables, contants, strings and numbers.

Here I learned about:

Variables (var) as containers that have interchangable contents
Constants (let) as containers that can only be declare once and can never be changed.
Strings are groups of characters started and ending with double quotes.
Can be used with modifiers like uppercased() etc
Numbers are called integers
Nubmers with decimals are floating-point numbers and is called “Double”
You cannot mix Integers and Doubles
You cannot mix strings with integers

Here is my code. I have heavily commented for now so that i can force myself to know what is happening.

import Cocoa

var greeting = "Hello, playground" // declare variable named "greeting" the string "Hello, Playground"

var name = "Ted" // declare a variable named "name" and initialize with the string "Ted"
  name = "Rebecca" // replace contents of the variable to "Rebecca"
  name = "Keeley" // replace contents of variable "name" from "Rebecca" to "Keeley"

let character = "Daphne" // declare a constant named "character" and initialize with the string "Daphne"
 // character = "Eloise"    // not possible for constants
 // character = "Francesca" // not possible for constants

var playerName = "Roy" // declare variable named "playerName" and initialize with string "Roy"
print(playerName)  // print the value of playerName on console

playerName = "Dani" // assign new value - "Dani" to playerName
print(playerName) // print new value of playername (which should be Dani now)

playerName = "Sam" // assign new value from "Dani" to "Sam"
print(playerName) // print new value for playerName on console (should be sam)

// Demonstrating camelcase convention. start with lowercase then capitalize every first letter of the word.

let managerName = "Michael Scott" // declare new variable named "manageName" containing "Michael Scott" String.
let dogBreed = "Samoyed" // declare variable named "dogBreed" container "Samoyed" string.
let meaningOfLife = "How many roads must a man walk down?" // declare variable named meaningOfLife.

// STRING - characters like in a scrabble game. Should start and end with a double quote (")

let actor = "Denzel Washington" // declare a string variable anmed actor.
let filename = "paris.jpg" // decalre a string variable with punctuations (.).
let result = "⭐ You win! ⭐" // declare a string variable with an emoji

// using double quotes in  a string, but you need to put a backslash (\)  to "escape" the character

let quote = "Then he tapped a sign saying \"Believe\" and walked away."  // declare a string variable with double quotes along with the slash.

// Swift does not like line breaks within strings. commenting the lines below since they will cause the compiler not to run. therefore line 40 to 42 will not work.

// let movie = "A day in
// the life of an engineer
// Apple engineer"

// use triple quotes to enable line breaks within strings

let movie = """
a day in
the life of an
apple engineer
"""  // declare a multiine variable using triple quotes.

// Some string based "modifiers"

print(actor.count) // count the number of characters in the string saved in the actor variable which is btw "Denzel Washington" and then print the result to console

print(result.uppercased()) // convert all characters to uppercase and pritn to console.

print(movie.hasPrefix("A day")) // return true if the variable "movie" has a string that starts with "A day"

print(filename.hasSuffix(".jpg")) // return true if the variable filename ends with ".jpg"

// How to store whole numbers

let score = 10 // declare a constant with a integer value of 10
let reallyBig = 100000000 // declare a long number, hard to read with the comma's
let reallyBig_with_breaks = 100_000_000 // use underscores to break up numbers for visual purposes.

// mathemetical operations for integers

let lowerScore = score - 2 // declare a constant with the value of score less 2
let higherScore = score + 10 // decllare a cosntant with the value of score plus 10
let doubledScore = score * 2 // declare a constant with the value of score multiplied by 2
let squaredScore = score * score // declare a constant with the value of score squared
let halvedScore = score / 2 // declare a constant with the value of score divided by two

// Counters using variables

var counter = 10 // declare a variable named counter and initialize with the integer 10
counter = counter + 5  // Add 5 to the value of counter and save it as the new value of counter

counter += 5 // Add 5 to the value of counter and save it as the new value of counter (short hand version of line 79) also known as "compound assignment operator"

counter *= 2 // multiply the value of counter by 2 and then replace it with the new value.
print(counter)  // print the value of counter

counter -= 10 // deduct 10 from the value of counter and replace it with the difference.
print(counter) // print the value of counter

counter /= 2 // divide the value of counter by 2 and replace it with the quotient.
print(counter)

// useful modifiers for integers

let number = 120 // declare a constant called number
print(number.isMultiple(of: 3))  // use isMultiple(of:) to determine if the value of number is a multiple of 3 - should return true.

// how to store floating-pint numbers - ie numbers with decimal places

// a complex way of storing floating point numbers:
let number_complex = 0.1 + 0.2 // declaring number_complex since number has been delcared earlier in this file.
print(number_complex)

// * Swift consider floating point numbers as a "Double" (short for double-procession flouting point number"
// You cannot mix Double's with Integers

let a = 1 // declare constant a
let b = 2.0 // delcare constant b
// let c = a + b // Not going to work which is why this line is commented.

let c_int = a + Int(b) // convert B from double to integer
let c_double = Double(a) + b // convert A from integer to double

let double1 = 3.1 // declare double1 as floating point
let double2 = 3131.3131 // declare double2 as floating point
let double3 = 3.0 // decalre double3 as floating point
let int1 = 3 // declare int1 as integer

var name_actor = "Nicholas Cage" // declare variable "name"
name = "John Travolta" // replace "Nicholas Cage" with "John Travolta" reference to Face-off movie.

// This will not work
var name_actor_acgain = "Nicholas cage"
// name = 57 // will not work which is why this line is commented

// Decimal numbers will also work with compound assignment operators

var rating = 5.0
rating *= 2

Also saved the ocde in my Gitlab / Github repositories.

#100daysofSwiftUI #learntocode