My Swift Journey - The Basics
11 November 2017
I am currently learning Swift to expand my programming knowledge. I looked at Swift a few years ago, but am now ready to dive into it.
I have programmed for many years with Java, and have some familiarity with Python. So, my approach to learning a new language is influenced by that previous knowledge. For example, I already know what a loop is. With Swift, I want to know the available control flow statements and their syntax. This is different from when I first learned to program and I had to learn the concept of a loop besides the syntax.
I am hoping to learn concepts that are not present in Java. I also want to see how another language approaches typical programming concepts.
This post contains my notes on Swift’s basic syntax, ranges and tuples. These notes are not an exhaustive resource. I plan to create posts on other concepts as I continue on my learning path.
Syntax Basics
| Syntax/Concept | Swift |
|---|---|
| semicolons | Semicolons can be used to separate lines, but it is recommend not too. Semicolons are required if there are multiple statements on one line. |
| comments | Same as Java. |
| parentheses | Are not needed around conditional statements. This is different from Java where they are needed. |
| curly braces | Are required after conditional or loop statements. In Java they are not required. This can lead to bugs because code thought to be in a conditional/loop block is not. Swift avoids this potential error by requiring the curly braces. |
| type inference | Swift can infer type. Integer and Double are the default type vs Unsigned Integer or Float. Float or Unsigned Integer must be explicitly declared if those types are needed. |
| constant declaration | let keyword. Swift prefers the use of constants over variables. |
| variable declaration | var keyword. |
| logical operators (NOT, AND, OR) | Same as Java |
| string interpolation | \(variable) in a String |
Examples:
//constant declaration, with type inference
let x = 3
//constant declaration, with type annotation
let tax : Float = 0.7
//variable declaration, with type inference
var y = "Apple"
//variable declaration, with type annotation
var title : String = "Harry Potter And The Half Blood Prince"
//conditionals do not need parentheses, but do need curly braces
let a = true
let b = false
let c = false
if a == b {
print("They are the same!")
}else {
print("They are different")
}
//logical operators
if a && b || !c {
print("in code block")
}
//string interpolation
let name = "Snoopy"
print("Hello \(name)")
Ranges
I like the range operators in Swift. They are intuitive and concise to work with.
| Swift | Notes |
|---|---|
| a…b | a and b are inclusive. Called the “Closed Range Operator” |
| a..<b | includes a, but excludes b. Called the “Half Open Range Operator” |
| [2…] | One sided range. In this example get all array items starting at index 2. |
| [..<2] | One sided range. In this example get all array items up to but excluding index 2. |
Examples:
//Closed Range Operator.
for x in 1...3 {
print(x)
}
//Half Open Range Operator
for x in 1..<3 {
print(x)
}
//One sided ranges
let fruits = ["apple", "banana", "peach", "grape"]
for fruit in fruits[1...] {
print(fruit)
}
for fruit in fruits[..<2] {
print(fruit)
}
Tuples
- Hurray! Swift has Tuples! I liked using them in Python and am glad Swift includes them. :)
- Swift also supports named tuples. Tuple values can be accessed by name rather than by index value.
Example:
//Named tuple
let t = (currencyName: "CAD", exchangeRate: 1.2, id: 4)
print(t.currencyName)
First Impressions
So far, I like Swift! The syntax is easy to read and concise to write. I also like it is a type-safe language. I am looking forward to learning more!
Thank you for reading! If you notice anything I missed or got wrong, please let me know! :)
