DEV Community: Joshua Rutkowski

Which Star Trek technologies do you want to see come to life?

Joshua Rutkowski — Fri, 27 Sep 2019 14:51:43 +0000

On September 8, 1966, NBC aired the first episode of a new TV series about a starship on a five year mission of space exploration. Since then, the Star Trek universe has coninued to feature amazing "futuristic" technologies.

Some technologies that we've now seen developed:

✔️ Tablet computers
✔️ Tricorders (mobile phones)
✔️ Voice-interface computers
✔️ Wearable computers/communicators
✔️ Portable memory

What are some things seen in Star Trek that you'd like to see finally developed?

A 4-day workweek?

Joshua Rutkowski — Fri, 27 Sep 2019 11:13:32 +0000

Recently, I came across the following article on The case for a 4-day workweek.

What are your thoughts? How would your productivity alter by working one less day per week but getting paid the same? 💵

Intro to Swift: Strings and Arithmetic

Joshua Rutkowski — Fri, 27 Sep 2019 10:35:41 +0000

In this lesson, you’ll learn some of the fundamentals for using strings and arithmetic in Swift.

Objectives:

Learn to create static strings using string literal syntax
Learn to concatenate strings
Learn to use string interpolation to include variable values in a string
Learn to use arithmetic operators to add, subtract, multiply, and divide variables
Learn to use comments to make code easier to understand

Note: This lessons roughly follows along Lambda School's iOS 101 precourse work. For additional information on Lambda School's iOS Development course, click here.

Learn to create static strings using string literal syntax

A string is a series of characters, such as "hello, world" or "starship". 🚀

Swift strings are represented by the String type. The simplest way to create a string in Swift is to use a string literal. A string literal is a sequence of characters surrounded by double quotation marks ("). For example:

let name = "Benjamin Sisko"

Note that Swift infers a type of String for the name constant because it’s initialized with a string literal value. In the above example, "Benjamin Sisko" is a string literal. You use string literals to initialize string constants or variables, but you can also use them anywhere a string is required.

Multi-line String Literals

If you need a string that spans several lines, use a multiline string literal—a sequence of characters surrounded by three double quotation marks:

let picardQuotation = """
Someone once told me that time was a predator that stalked us all our lives. 
I rather believe that time is a companion who goes with us on the journey 
and reminds us to cherish every moment, because it will never come again. 

What we leave behind is not as important as how we've lived. 
After all Number One, we're only mortal.
"""

It’s important that the string start on the next line after the opening quotes, and that the closing quotes also are on the line after the end of the string.

Learn to concatenate strings

Concatenation refers to combining two or more strings together to make a new string. To concatenate strings in Swift, you use the + operator.

let string1 = "Live long"
let string2 = "prosper"

let spockGreeting = string1 + " and " + string2
print(spockGreeting) //Live long and prosper

Learn to use string interpolation to include variable values in a string

String interpolation allows you create a string that includes the value of constants or variables. Let's say you have an integer that represents the number of starships Starfleet has. 🚀

You want to print a string that says “Starfleet has ___ starships.”. String interpolation can be used to create this string.

let numberOfShips = 450
let stringToPrint = "Starfleet has \(numberOfShips) starships."
print(stringToPrint) //Startfleet has 450 starships.

In the example above, the value of numberOfShips is inserted into a string literal as \(numberOfShips). This placeholder is replaced with the actual value of numberOfShips when the string interpolation is evaluated to create an actual string.

Learn to use arithmetic operators to add, subtract, multiply, and divide variables

There are four basic arithmetic operators: add (+), subtract (-), multiply (*), and divide (/). You can use them directly on numbers, or on constants or variables.

Addition, subtraction, and multiplication

These operators work the way you’d expect. For example:

let answer = 2 * 14
let score = 1 + 2 + 3

let birthYear = 1901
let currentYear = 2019
let age = currentYear - birthYear

Division

Remember from our previous lesson that Int (and UInt) values can only store whole numbers. When you divide two Intsby each other, the result will also be an Int, and will be the result of the division rounded down to the nearest whole number.

let x = 5
let y = 2
let result = x / y 
print(result) // 2

If you’re doing division and need fractional values, you should use floating point numbers (see previous lesson on type annotations):

let x: Double = 5
let y: Double = 2
let result = x / y
print(result) // 2.5

Learn to use comments to make code easier to understand

You should always strive to write code that is clear and easy for humans to understand. Usually, this should mean that the code itself is nicely written, well-formatted, your variables have carefully chosen names, etc.

However, sometimes, it’s useful to be able to write little comments to explain what a particular part of the code is doing. Comments are notes to you or another future reader of the code, but the compiler ignores them.

There are two ways to create comments in Swift. You can create a comment on the same line as some code by prefixing your comment with two forward slashes ():

let birthYear = 1988
let currentYear = 2019
let age = currentYear - birthYear // Calculate current age
print(age)

Anything after the slashes will be ignored until the next line break.

If you want to write a comment that spans multiple lines, you can put your comments between /*and */:

/* This is a longer comment.
It has multiple lines.
The compiler ignores everything here.
*/

Challenge

Now it's your turn! Go ahead and try the following challenges and post your results below! Don't have macOS to run your Swift code? No worries, head on over to repl.it - an online Swift Editor and IDE!

String Literals: Create a string literal constant introducing yourself. Your introduction should include your name, where you're from, what you like to do for fun, etc.

String Concatenation: Create a constant for your favorite vacation destination. Using string concatenation, print out a string that says "I love to travel to [favorite travel destination]."

String Interpolation: Using the constant you created above, print out the same string: "I love to travel to [favorite travel destination]." using string interpolation

Calorie Goal: Below you have constants for the number of calories you burned each day over the last week. Using simple arithmetic find the average number of calories burned. Add 100 calories to the average and use string interpolation to print out "Your new move goal for the week is [your calculated goal].

let mondayCalories = 340
let tuesdayCalories = 420
let wednedayCalories = 200
let thursdayCalories = 625
let fridayCalories = 500
let saturdayCalories = 1_090
let sundayCalories = 300

Like this post?

You can find more by following me on twitter 😄: @joshuarutkowski

Thanks for reading!

Intro to Swift: Constants and Variables

Joshua Rutkowski — Wed, 25 Sep 2019 21:36:55 +0000

This lesson is a companion to my Twitter ✨Intro to Swift✨ crash course - Check it out! 👌

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The lesson introduces you to the Swift programming language and mainly covers constants and variables and the print statement.

Objectives for this lesson:

Learn to use Xcode to create a playground
Learn to use print() to output text to the console
Learn to use constants (let) to store values
Learn to use variables (var) to store and change values
Learn when to use var vs let
Learn to use different types of variables and constants, including Int, Float, Bool, etc.

The lesson concludes with the following Challenge:

Create variables and constants for various parts about you, such as your name, your hometown, your favorite color and food, and anything else you think someone would be interested to know about you. Think about which of these should be variables, and which should be constants. Try to come up with at least 8 constants and variables in total.

Print each of these using print() statements and inserting the variable or constant in the parentheses.

Note: This lessons follows along Lambda School's iOS 101 precourse work. For additional information on Lambda School's iOS Development course, click here.

Learn to use Xcode to create a playground

Xcode includes a feature called playgrounds. Playgrounds provides a testing ground that renders developer code in real time.

To start a new playground, open Xcode and select "Get started with a playground." Don't have macOS or Xcode? No worries, head on over to repl.it

Learn to use `print()` to output text to the console

In its simplest form, a print statement looks like this:

print("Text you want to output here")

In Xcode, the print() function prints its output in Xcode’s “console” pane, as seen below.

Learn to use constants (`let`) to store values

Constants associate a name (such as numberOfPizzaSlicesEaten or welcomeMessage) with a value of a particular type (such as the number 4 or the string "Hello"). The value of a constant can’t be changed once it’s set.

Constants must be declared before they’re used. You declare constants with the let keyword:

let numberOfPizzaSlicesEaten = 8

This code can be read as: "Declare a new constant called numberOfPizzaSlicesEaten, and give it a value of 8."

A note about naming: You can name constants anything you like, with a few small restrictions. The biggest one to remember is that constant names can’t start with a number (though they can contain a number elsewhere). The names you choose for your constants are important. Writing code that is easy for you (and other humans) to read and understand is a vital part of being a good programmer. So choose names that are concise but very clearly convey the purpose of a constant. You should avoid the temptation to abbreviate names. An example of a poorly written constant:

let numberOfZaSlicesEaten = 8

You may understand that "Za" means "Pizza" - however, it may be difficult for another person reviewing your code to understand the reference. Also, no self-respecting person uses "za." 🍕

Learn to use variables (`var`) to store and change values

Like a constant, variables associate a name with a value of a particular type. Unlike a constant, variables can be given new values as the program runs. To create a variable, use a var statement.

Here’s an example of how constants and variables can be used to track the number of pizza slices a user has eaten:

let numberOfPizzaSlicesEaten = 8
var currentPizzaSlice = 2

In this example, the maximum number of allowed pizza slices to be eaten is declared as a constant, because the maximum value never changes. The current pizza slice counter is declared as a variable, because this value must be incremented after each slice is eaten.

Learn when to use `var` vs `let`

Rule of thumb: If you have a value that needs to change, you should use a variable. If you have a value that never changes, use a constant.

You might think that always using variables makes sense, because you can change them if you need to, or leave them the same. In fact, many languages don’t have constants, and only use variables. However, this is not a good idea in practice.

In fact, as you read and write more and more Swift you’ll notice that variables are actually quite rarely used. As a rule of thumb, you should always make your values constants with let. If, and only if, you actually need a value that can change, should you change your value to a variable.

If you have a value that needs to change, you should use a variable. If you have a value that never changes, use a constant.

Learn to use different types of variables and constants, including Int, Float, Bool, etc.

Normally, Swift is able to figure out, or infer the type of a value based on context. It’s clear that 42 is an integer, or Int, not a string. Similarly, “Hello” is obviously not a number, it’s a String. This feature is called type inference and is one of the things that makes Swift concise and nice to write.

You can provide a type annotation when you declare a constant or variable, to be clear about the kind of values the constant or variable can store. Write a type annotation by placing a colon after the constant or variable name, followed by a space, followed by the name of the type to use.

String

This example provides a type annotation for a variable called typeOfPizzaEaten, to indicate that the variable can store String values:

var typeOfPizzaEaten: String = "margherita"

The colon in the declaration means “…of type…,” so the code above can be read as: “Declare a variable called typeOfPizzaEaten that is of type String, and give it the value "margherita".”

The phrase “of type String” means “can store any String value.” Think of it as meaning “the type of thing” (or “the kind of thing”) that can be stored.

Number Types

There are actually multiple number types, including Int, UInt, Float, and Double. Int is short for integer and is a whole number that can be either positive or negative. UInt is an unsigned integer, and is a whole number but it can only be positive. In other words, it can’t have a minus sign. You’ll see both types used in Swift, but Int is more common, and is the default. Float and Double are both kinds of floating point numbers.

Floating point numbers are numbers with a decimal point like 3.14. The difference between Float and Double is their precision, and the maximum value they can store. Double is more precise and can store larger numbers than a Float. However, it also takes up twice as much memory space as a Float. You’ll see both types used in Swift, but Double is more common, and is the default.

Boolean

Another common type is Bool, which is short for boolean. Boolean values can only be either true or false. We could create a boolean variable like so:

let pizzaIsAwesome = true

Challenge

Let's put our knowledge of constants, variables, and type annotations together, and see if we can complete the Challenge:

Create variables and constants for various parts about you, such as your name, your hometown, your favorite color and food, and anything else you think someone would be interested to know about you. Think about which of these should be variables, and which should be constants. Try to come up with at least 8 constants and variables in total.

Print each of these using print() statements and inserting the variable or constant in the parentheses.

Give it a shot before scrolling down! 😉

var myAge: UInt = 78 
let myFavoriteColor: String = "Aquamarine Blue"
let myFavoriteFood: String = "Sushi"
let firstName: String = "Arthur"
let lastName: String = "Curry"
let birthYear: Int = 1941
let homeTown: String = "Atlantis"
let university: String = "School of Hard Knocks"
let occupation: String = "Lighthouse Keeper"

print(firstName)
print(lastName)
print(birthYear)
print(myFavoriteFood)
print(myFavoriteColor)
print(homeTown)
print(university)
print(occupation)

Bonus Challenge

Now it's your turn!

Create a constant called introduction. This should be a readable sentence or paragraph that includes all of the constants and variables you made and combines them into a single string.

Hints: Look up string interpolation in Swift to learn how to turn variables into text. Google is your friend here. 😉

Note: We will cover string interpolation in detail in a later lesson, so don't worry if you don't already know it, or find it confusing at first.

Like this post?

You can find more by following me on twitter 😄: @joshuarutkowski

Thanks for reading!

Is English a necessary skill for a developer? Why or why not?

Joshua Rutkowski — Sun, 22 Sep 2019 20:19:39 +0000

Like the title says - is English a necessary skill for a developer? What do you think?

[Deleted User]

Accepted to Lambda School's iOS Development Course!

Joshua Rutkowski — Thu, 19 Sep 2019 14:36:46 +0000

Very excited to announce that I was accepted into Lambda School’s iOS Development Course. So excited to be accepted into a top-tier software engineering program!

I chose the start date of October 28th for the Part-Time program and I’m very excited about this new journey. Working 40+ hours a week and participating in the iOS course part-time is going to be challenge - but the sacrifice is worth it!

For anyone who is in Lambda or is an alumni, please, feel free to follow and send encouraging words.

I'll be documenting my journey - stay tuned!

Follow along on Twitter

DEV Community: Joshua Rutkowski

Which Star Trek technologies do you want to see come to life?

A 4-day workweek?

Intro to Swift: Strings and Arithmetic

Objectives:

Learn to create static strings using string literal syntax

Multi-line String Literals

Learn to concatenate strings

Learn to use string interpolation to include variable values in a string

Learn to use arithmetic operators to add, subtract, multiply, and divide variables

Addition, subtraction, and multiplication

Division

Learn to use comments to make code easier to understand

Challenge

Like this post?

Intro to Swift: Constants and Variables

Learn to use Xcode to create a playground

Learn to use print() to output text to the console

Learn to use constants (let) to store values

Learn to use variables (var) to store and change values

Learn when to use var vs let

Learn to use different types of variables and constants, including Int, Float, Bool, etc.

String

Number Types

Boolean

Challenge

Bonus Challenge

Like this post?

Is English a necessary skill for a developer? Why or why not?

[Deleted User]

Accepted to Lambda School's iOS Development Course!

Learn to use `print()` to output text to the console

Learn to use constants (`let`) to store values

Learn to use variables (`var`) to store and change values

Learn when to use `var` vs `let`