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Day 1

Saurabh Jamadagni
27th June, 2022

Programming is an art: don't spend all your time sharpening your pencil when you should be drawing.

  • SwiftUI is framework used to build apps for the myriad of apple devices based on the Swift language.

Why Swift?

  • Swift is a fairly young language launched in 2014.
  • This allows the language to take advantage and builds upon the successes of other languages.
  • Swift makes it
    • difficult to write unsafe code.
    • easy to write code with clarity
    • possible to work with all other languages.
  • It is also a very powerful language!

How to follow along?

  • You will require Xcode 13 or later which can be downloaded on the app store for free.
  • Playgrounds is a great place to experiment and practise concepts of swift.

Creating Variables and Constants

  • There are two ways to store data in swift
  • Create a variable when you want to change the data later or know that the data will change down the line.
  • To create a variable the var keyword is used using the syntax var variableName = value
  • Creating a constant is similar to creating a variable. Use the let keyword instead of var.
  • Prefer using constants. It will help you avoid changing variables on accident which should not have been changed.
var mood = "Happy"
// variables can be reassigned
mood = "excited"

// constants cannot be reassigned
let pain = "constant"

Working with Strings

  • Strings in swift are followed by double quotes.
  • They can contain special characters, emojis along with normal text. Use the \ escape operator wherever necessary.
  • Multi-line strings use triple quotes.
// Multi-line strings
let fact = """
Exercising is
good for
YOU!
"""

  • Some of the special properties and methods that strings in swift have are

    • count -> tells you the number of characters in a string
    • uppercased() -> makes all the characters in the string uppercase.
    • hasPrefix(prefix) -> takes the prefix as argument. Returns a boolean
    • hasSuffix(suffix) -> takes the suffix as argument. Returns a boolean

  • This is very basic information about strings. Strings will be further explored more down the road.

Working with Integers

  • Use underscore _ to make large numbers readable. Example, 10_000_000
  • Use shorthand operators to avoid redundant variables.
// multiplication shorthand operator used to multiply variable by 100 and store the result in itself.
var confidence = 100_000
confidence *= 100
  • Integers also have some special properties and functions that are very powerful and useful.
    • One of which is isMultiple(of: num) -> checks if the given number is a multiple of num. Returns a boolean.

Working with Decimals

  • Decimals are not as accurate as Integers because of the floating point.
  • This is because the data is stored in binary. Some numbers are not possible to be stored in binary due to their recurring nature. Example 1/3 = 0.333333333...
  • You will also see one more data type thrown around known as CGFloat. It is part of CoreGraphics and can be interchangably used with Double
  • Decimals are a completely different data type than integers. You cannot carry operations across data types. Some form of conversion has to be made.

Summary

Swift is a powerful programming language that is used to work with SwiftUI. On day 1, concepts such as variables and constants, working with integers, strings and doubles were discussed. Create a variable when you want to change the data or the data will change due to some operation. Else prefer constants. Integers and variables are handled differently. Also learned about Strings & multi-line strings.

Thanks for reading! Let's connect on Twitter 👋