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Merge branch 'master' of github.com:adambard/learnxinyminutes-docs
This commit is contained in:
commit
171f179f6e
@ -5,6 +5,7 @@ contributors:
|
|||||||
- ["George Petrov", "http://github.com/petrovg"]
|
- ["George Petrov", "http://github.com/petrovg"]
|
||||||
- ["Dominic Bou-Samra", "http://dbousamra.github.com"]
|
- ["Dominic Bou-Samra", "http://dbousamra.github.com"]
|
||||||
- ["Geoff Liu", "http://geoffliu.me"]
|
- ["Geoff Liu", "http://geoffliu.me"]
|
||||||
|
- ["Ha-Duong Nguyen", "http://reference-error.org"]
|
||||||
filename: learn.scala
|
filename: learn.scala
|
||||||
---
|
---
|
||||||
|
|
||||||
@ -16,15 +17,16 @@ Scala - the scalable language
|
|||||||
Set yourself up:
|
Set yourself up:
|
||||||
|
|
||||||
1) Download Scala - http://www.scala-lang.org/downloads
|
1) Download Scala - http://www.scala-lang.org/downloads
|
||||||
2) unzip/untar in your favourite location and put the bin subdir on the path
|
2) Unzip/untar to your favourite location and put the bin subdir in your `PATH` environment variable
|
||||||
3) Start a scala REPL by typing scala. You should see the prompt:
|
3) Start a Scala REPL by running `scala`. You should see the prompt:
|
||||||
|
|
||||||
scala>
|
scala>
|
||||||
|
|
||||||
This is the so called REPL (Read-Eval-Print Loop). You may type any valid
|
This is the so called REPL (Read-Eval-Print Loop). You may type any Scala
|
||||||
Scala expression into it, and the result will be printed. We will explain what
|
expression, and the result will be printed. We will explain what Scala files
|
||||||
Scala files look like further into this tutorial, but for now, let's start
|
look like further into this tutorial, but for now, let's start with some
|
||||||
with some basics.
|
basics.
|
||||||
|
|
||||||
*/
|
*/
|
||||||
|
|
||||||
|
|
||||||
@ -32,10 +34,10 @@ Scala - the scalable language
|
|||||||
// 1. Basics
|
// 1. Basics
|
||||||
/////////////////////////////////////////////////
|
/////////////////////////////////////////////////
|
||||||
|
|
||||||
// Single line comments start with two forward slashes
|
// Single-line comments start with two forward slashes
|
||||||
|
|
||||||
/*
|
/*
|
||||||
Multi line comments, as you can already see from above, look like this.
|
Multi-line comments, as you can already see from above, look like this.
|
||||||
*/
|
*/
|
||||||
|
|
||||||
// Printing, and forcing a new line on the next print
|
// Printing, and forcing a new line on the next print
|
||||||
@ -46,7 +48,7 @@ println(10)
|
|||||||
print("Hello world")
|
print("Hello world")
|
||||||
|
|
||||||
// Declaring values is done using either var or val.
|
// Declaring values is done using either var or val.
|
||||||
// val declarations are immutable, whereas var's are mutable. Immutability is
|
// val declarations are immutable, whereas vars are mutable. Immutability is
|
||||||
// a good thing.
|
// a good thing.
|
||||||
val x = 10 // x is now 10
|
val x = 10 // x is now 10
|
||||||
x = 20 // error: reassignment to val
|
x = 20 // error: reassignment to val
|
||||||
@ -176,7 +178,7 @@ addWithDefault(1) // => 6
|
|||||||
|
|
||||||
|
|
||||||
// Anonymous functions look like this:
|
// Anonymous functions look like this:
|
||||||
(x:Int) => x * x
|
(x: Int) => x * x
|
||||||
|
|
||||||
// Unlike defs, even the input type of anonymous functions can be omitted if the
|
// Unlike defs, even the input type of anonymous functions can be omitted if the
|
||||||
// context makes it clear. Notice the type "Int => Int" which means a function
|
// context makes it clear. Notice the type "Int => Int" which means a function
|
||||||
@ -218,19 +220,19 @@ def foo(x: Int): Int = {
|
|||||||
|
|
||||||
1 to 5
|
1 to 5
|
||||||
val r = 1 to 5
|
val r = 1 to 5
|
||||||
r.foreach( println )
|
r.foreach(println)
|
||||||
|
|
||||||
r foreach println
|
r foreach println
|
||||||
// NB: Scala is quite lenient when it comes to dots and brackets - study the
|
// NB: Scala is quite lenient when it comes to dots and brackets - study the
|
||||||
// rules separately. This helps write DSLs and APIs that read like English
|
// rules separately. This helps write DSLs and APIs that read like English
|
||||||
|
|
||||||
(5 to 1 by -1) foreach ( println )
|
(5 to 1 by -1) foreach (println)
|
||||||
|
|
||||||
// A while loops
|
// A while loops
|
||||||
var i = 0
|
var i = 0
|
||||||
while (i < 10) { println("i " + i); i+=1 }
|
while (i < 10) { println("i " + i); i += 1 }
|
||||||
|
|
||||||
while (i < 10) { println("i " + i); i+=1 } // Yes, again. What happened? Why?
|
while (i < 10) { println("i " + i); i += 1 } // Yes, again. What happened? Why?
|
||||||
|
|
||||||
i // Show the value of i. Note that while is a loop in the classical sense -
|
i // Show the value of i. Note that while is a loop in the classical sense -
|
||||||
// it executes sequentially while changing the loop variable. while is very
|
// it executes sequentially while changing the loop variable. while is very
|
||||||
@ -239,19 +241,19 @@ i // Show the value of i. Note that while is a loop in the classical sense -
|
|||||||
|
|
||||||
// A do while loop
|
// A do while loop
|
||||||
do {
|
do {
|
||||||
println("x is still less than 10");
|
println("x is still less than 10")
|
||||||
x += 1
|
x += 1
|
||||||
} while (x < 10)
|
} while (x < 10)
|
||||||
|
|
||||||
// Tail recursion is an idiomatic way of doing recurring things in Scala.
|
// Tail recursion is an idiomatic way of doing recurring things in Scala.
|
||||||
// Recursive functions need an explicit return type, the compiler can't infer it.
|
// Recursive functions need an explicit return type, the compiler can't infer it.
|
||||||
// Here it's Unit.
|
// Here it's Unit.
|
||||||
def showNumbersInRange(a:Int, b:Int):Unit = {
|
def showNumbersInRange(a: Int, b: Int): Unit = {
|
||||||
print(a)
|
print(a)
|
||||||
if (a < b)
|
if (a < b)
|
||||||
showNumbersInRange(a + 1, b)
|
showNumbersInRange(a + 1, b)
|
||||||
}
|
}
|
||||||
showNumbersInRange(1,14)
|
showNumbersInRange(1, 14)
|
||||||
|
|
||||||
|
|
||||||
// Conditionals
|
// Conditionals
|
||||||
@ -305,13 +307,13 @@ s(1)
|
|||||||
(a, 2, "three")
|
(a, 2, "three")
|
||||||
|
|
||||||
// Why have this?
|
// Why have this?
|
||||||
val divideInts = (x:Int, y:Int) => (x / y, x % y)
|
val divideInts = (x: Int, y: Int) => (x / y, x % y)
|
||||||
|
|
||||||
divideInts(10,3) // The function divideInts gives you the result and the remainder
|
divideInts(10, 3) // The function divideInts gives you the result and the remainder
|
||||||
|
|
||||||
// To access the elements of a tuple, use _._n where n is the 1-based index of
|
// To access the elements of a tuple, use _._n where n is the 1-based index of
|
||||||
// the element
|
// the element
|
||||||
val d = divideInts(10,3)
|
val d = divideInts(10, 3)
|
||||||
|
|
||||||
d._1
|
d._1
|
||||||
|
|
||||||
@ -446,7 +448,7 @@ def matchEverything(obj: Any): String = obj match {
|
|||||||
case List(1, b, c) => s"Got a list with three elements and starts with 1: 1, $b, $c"
|
case List(1, b, c) => s"Got a list with three elements and starts with 1: 1, $b, $c"
|
||||||
|
|
||||||
// You can nest patterns:
|
// You can nest patterns:
|
||||||
case List(List((1, 2,"YAY"))) => "Got a list of list of tuple"
|
case List(List((1, 2, "YAY"))) => "Got a list of list of tuple"
|
||||||
}
|
}
|
||||||
|
|
||||||
// In fact, you can pattern match any object with an "unapply" method. This
|
// In fact, you can pattern match any object with an "unapply" method. This
|
||||||
@ -493,7 +495,7 @@ sSquared.reduce (_+_)
|
|||||||
// The filter function takes a predicate (a function from A -> Boolean) and
|
// The filter function takes a predicate (a function from A -> Boolean) and
|
||||||
// selects all elements which satisfy the predicate
|
// selects all elements which satisfy the predicate
|
||||||
List(1, 2, 3) filter (_ > 2) // List(3)
|
List(1, 2, 3) filter (_ > 2) // List(3)
|
||||||
case class Person(name:String, age:Int)
|
case class Person(name: String, age: Int)
|
||||||
List(
|
List(
|
||||||
Person(name = "Dom", age = 23),
|
Person(name = "Dom", age = 23),
|
||||||
Person(name = "Bob", age = 30)
|
Person(name = "Bob", age = 30)
|
||||||
@ -594,7 +596,7 @@ import scala.collection.immutable._
|
|||||||
import scala.collection.immutable.{List, Map}
|
import scala.collection.immutable.{List, Map}
|
||||||
|
|
||||||
// Rename an import using '=>'
|
// Rename an import using '=>'
|
||||||
import scala.collection.immutable.{ List => ImmutableList }
|
import scala.collection.immutable.{List => ImmutableList}
|
||||||
|
|
||||||
// Import all classes, except some. The following excludes Map and Set:
|
// Import all classes, except some. The following excludes Map and Set:
|
||||||
import scala.collection.immutable.{Map => _, Set => _, _}
|
import scala.collection.immutable.{Map => _, Set => _, _}
|
||||||
@ -629,13 +631,8 @@ writer.close()
|
|||||||
|
|
||||||
## Further resources
|
## Further resources
|
||||||
|
|
||||||
[Scala for the impatient](http://horstmann.com/scala/)
|
* [Scala for the impatient](http://horstmann.com/scala/)
|
||||||
|
* [Twitter Scala school](http://twitter.github.io/scala_school/)
|
||||||
[Twitter Scala school](http://twitter.github.io/scala_school/)
|
* [The scala documentation](http://docs.scala-lang.org/)
|
||||||
|
* [Try Scala in your browser](http://scalatutorials.com/tour/)
|
||||||
[The scala documentation](http://docs.scala-lang.org/)
|
* Join the [Scala user group](https://groups.google.com/forum/#!forum/scala-user)
|
||||||
|
|
||||||
[Try Scala in your browser](http://scalatutorials.com/tour/)
|
|
||||||
|
|
||||||
Join the [Scala user group](https://groups.google.com/forum/#!forum/scala-user)
|
|
||||||
|
|
||||||
|
@ -4,6 +4,7 @@ contributors:
|
|||||||
- ["Grant Timmerman", "http://github.com/grant"]
|
- ["Grant Timmerman", "http://github.com/grant"]
|
||||||
- ["Christopher Bess", "http://github.com/cbess"]
|
- ["Christopher Bess", "http://github.com/cbess"]
|
||||||
- ["Joey Huang", "http://github.com/kamidox"]
|
- ["Joey Huang", "http://github.com/kamidox"]
|
||||||
|
- ["Anthony Nguyen", "http://github.com/anthonyn60"]
|
||||||
filename: learnswift.swift
|
filename: learnswift.swift
|
||||||
---
|
---
|
||||||
|
|
||||||
@ -26,7 +27,9 @@ import UIKit
|
|||||||
// TODO: Do something soon
|
// TODO: Do something soon
|
||||||
// FIXME: Fix this code
|
// FIXME: Fix this code
|
||||||
|
|
||||||
println("Hello, world")
|
// In Swift 2, println and print were combined into one print method. Print automatically appends a new line.
|
||||||
|
print("Hello, world") // println is now print
|
||||||
|
print("Hello, world", appendNewLine: false) // printing without appending a newline
|
||||||
|
|
||||||
// variables (var) value can change after being set
|
// variables (var) value can change after being set
|
||||||
// constants (let) value can NOT be changed after being set
|
// constants (let) value can NOT be changed after being set
|
||||||
@ -46,12 +49,12 @@ let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation
|
|||||||
// Build Specific values
|
// Build Specific values
|
||||||
// uses -D build configuration
|
// uses -D build configuration
|
||||||
#if false
|
#if false
|
||||||
println("Not printed")
|
print("Not printed")
|
||||||
let buildValue = 3
|
let buildValue = 3
|
||||||
#else
|
#else
|
||||||
let buildValue = 7
|
let buildValue = 7
|
||||||
#endif
|
#endif
|
||||||
println("Build value: \(buildValue)") // Build value: 7
|
print("Build value: \(buildValue)") // Build value: 7
|
||||||
|
|
||||||
/*
|
/*
|
||||||
Optionals are a Swift language feature that allows you to store a `Some` or
|
Optionals are a Swift language feature that allows you to store a `Some` or
|
||||||
@ -69,7 +72,7 @@ var someOptionalString2: Optional<String> = "optional"
|
|||||||
if someOptionalString != nil {
|
if someOptionalString != nil {
|
||||||
// I am not nil
|
// I am not nil
|
||||||
if someOptionalString!.hasPrefix("opt") {
|
if someOptionalString!.hasPrefix("opt") {
|
||||||
println("has the prefix")
|
print("has the prefix")
|
||||||
}
|
}
|
||||||
|
|
||||||
let empty = someOptionalString?.isEmpty
|
let empty = someOptionalString?.isEmpty
|
||||||
@ -138,21 +141,21 @@ var emptyMutableDictionary = [String: Float]() // var == mutable
|
|||||||
let myArray = [1, 1, 2, 3, 5]
|
let myArray = [1, 1, 2, 3, 5]
|
||||||
for value in myArray {
|
for value in myArray {
|
||||||
if value == 1 {
|
if value == 1 {
|
||||||
println("One!")
|
print("One!")
|
||||||
} else {
|
} else {
|
||||||
println("Not one!")
|
print("Not one!")
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
// for loop (dictionary)
|
// for loop (dictionary)
|
||||||
var dict = ["one": 1, "two": 2]
|
var dict = ["one": 1, "two": 2]
|
||||||
for (key, value) in dict {
|
for (key, value) in dict {
|
||||||
println("\(key): \(value)")
|
print("\(key): \(value)")
|
||||||
}
|
}
|
||||||
|
|
||||||
// for loop (range)
|
// for loop (range)
|
||||||
for i in -1...shoppingList.count {
|
for i in -1...shoppingList.count {
|
||||||
println(i)
|
print(i)
|
||||||
}
|
}
|
||||||
shoppingList[1...2] = ["steak", "peacons"]
|
shoppingList[1...2] = ["steak", "peacons"]
|
||||||
// use ..< to exclude the last number
|
// use ..< to exclude the last number
|
||||||
@ -165,7 +168,7 @@ while i < 1000 {
|
|||||||
|
|
||||||
// do-while loop
|
// do-while loop
|
||||||
do {
|
do {
|
||||||
println("hello")
|
print("hello")
|
||||||
} while 1 == 2
|
} while 1 == 2
|
||||||
|
|
||||||
// Switch
|
// Switch
|
||||||
@ -222,8 +225,8 @@ let pricesTuple = getGasPrices()
|
|||||||
let price = pricesTuple.2 // 3.79
|
let price = pricesTuple.2 // 3.79
|
||||||
// Ignore Tuple (or other) values by using _ (underscore)
|
// Ignore Tuple (or other) values by using _ (underscore)
|
||||||
let (_, price1, _) = pricesTuple // price1 == 3.69
|
let (_, price1, _) = pricesTuple // price1 == 3.69
|
||||||
println(price1 == pricesTuple.1) // true
|
print(price1 == pricesTuple.1) // true
|
||||||
println("Gas price: \(price)")
|
print("Gas price: \(price)")
|
||||||
|
|
||||||
// Variadic Args
|
// Variadic Args
|
||||||
func setup(numbers: Int...) {
|
func setup(numbers: Int...) {
|
||||||
@ -251,7 +254,7 @@ func swapTwoInts(inout a: Int, inout b: Int) {
|
|||||||
var someIntA = 7
|
var someIntA = 7
|
||||||
var someIntB = 3
|
var someIntB = 3
|
||||||
swapTwoInts(&someIntA, &someIntB)
|
swapTwoInts(&someIntA, &someIntB)
|
||||||
println(someIntB) // 7
|
print(someIntB) // 7
|
||||||
|
|
||||||
|
|
||||||
//
|
//
|
||||||
@ -305,7 +308,7 @@ struct NamesTable {
|
|||||||
// Structures have an auto-generated (implicit) designated initializer
|
// Structures have an auto-generated (implicit) designated initializer
|
||||||
let namesTable = NamesTable(names: ["Me", "Them"])
|
let namesTable = NamesTable(names: ["Me", "Them"])
|
||||||
let name = namesTable[1]
|
let name = namesTable[1]
|
||||||
println("Name is \(name)") // Name is Them
|
print("Name is \(name)") // Name is Them
|
||||||
|
|
||||||
//
|
//
|
||||||
// MARK: Classes
|
// MARK: Classes
|
||||||
@ -386,7 +389,7 @@ let aShape = mySquare as Shape
|
|||||||
|
|
||||||
// compare instances, not the same as == which compares objects (equal to)
|
// compare instances, not the same as == which compares objects (equal to)
|
||||||
if mySquare === mySquare {
|
if mySquare === mySquare {
|
||||||
println("Yep, it's mySquare")
|
print("Yep, it's mySquare")
|
||||||
}
|
}
|
||||||
|
|
||||||
// Optional init
|
// Optional init
|
||||||
@ -409,13 +412,13 @@ class Circle: Shape {
|
|||||||
}
|
}
|
||||||
|
|
||||||
var myCircle = Circle(radius: 1)
|
var myCircle = Circle(radius: 1)
|
||||||
println(myCircle?.getArea()) // Optional(3)
|
print(myCircle?.getArea()) // Optional(3)
|
||||||
println(myCircle!.getArea()) // 3
|
print(myCircle!.getArea()) // 3
|
||||||
var myEmptyCircle = Circle(radius: -1)
|
var myEmptyCircle = Circle(radius: -1)
|
||||||
println(myEmptyCircle?.getArea()) // "nil"
|
print(myEmptyCircle?.getArea()) // "nil"
|
||||||
if let circle = myEmptyCircle {
|
if let circle = myEmptyCircle {
|
||||||
// will not execute since myEmptyCircle is nil
|
// will not execute since myEmptyCircle is nil
|
||||||
println("circle is not nil")
|
print("circle is not nil")
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
||||||
@ -447,7 +450,7 @@ enum BookName: String {
|
|||||||
case John = "John"
|
case John = "John"
|
||||||
case Luke = "Luke"
|
case Luke = "Luke"
|
||||||
}
|
}
|
||||||
println("Name: \(BookName.John.rawValue)")
|
print("Name: \(BookName.John.rawValue)")
|
||||||
|
|
||||||
// Enum with associated Values
|
// Enum with associated Values
|
||||||
enum Furniture {
|
enum Furniture {
|
||||||
@ -467,9 +470,9 @@ enum Furniture {
|
|||||||
}
|
}
|
||||||
|
|
||||||
var desk: Furniture = .Desk(height: 80)
|
var desk: Furniture = .Desk(height: 80)
|
||||||
println(desk.description()) // "Desk with 80 cm"
|
print(desk.description()) // "Desk with 80 cm"
|
||||||
var chair = Furniture.Chair("Foo", 40)
|
var chair = Furniture.Chair("Foo", 40)
|
||||||
println(chair.description()) // "Chair of Foo with 40 cm"
|
print(chair.description()) // "Chair of Foo with 40 cm"
|
||||||
|
|
||||||
|
|
||||||
//
|
//
|
||||||
@ -522,7 +525,7 @@ extension Square: Printable {
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
println("Square: \(mySquare)")
|
print("Square: \(mySquare)")
|
||||||
|
|
||||||
// You can also extend built-in types
|
// You can also extend built-in types
|
||||||
extension Int {
|
extension Int {
|
||||||
@ -535,8 +538,8 @@ extension Int {
|
|||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
|
||||||
println(7.customProperty) // "This is 7"
|
print(7.customProperty) // "This is 7"
|
||||||
println(14.multiplyBy(3)) // 42
|
print(14.multiplyBy(3)) // 42
|
||||||
|
|
||||||
// Generics: Similar to Java and C#. Use the `where` keyword to specify the
|
// Generics: Similar to Java and C#. Use the `where` keyword to specify the
|
||||||
// requirements of the generics.
|
// requirements of the generics.
|
||||||
@ -550,7 +553,7 @@ func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? {
|
|||||||
return nil
|
return nil
|
||||||
}
|
}
|
||||||
let foundAtIndex = findIndex([1, 2, 3, 4], 3)
|
let foundAtIndex = findIndex([1, 2, 3, 4], 3)
|
||||||
println(foundAtIndex == 2) // true
|
print(foundAtIndex == 2) // true
|
||||||
|
|
||||||
// Operators:
|
// Operators:
|
||||||
// Custom operators can start with the characters:
|
// Custom operators can start with the characters:
|
||||||
@ -566,9 +569,9 @@ prefix func !!! (inout shape: Square) -> Square {
|
|||||||
}
|
}
|
||||||
|
|
||||||
// current value
|
// current value
|
||||||
println(mySquare.sideLength) // 4
|
print(mySquare.sideLength) // 4
|
||||||
|
|
||||||
// change side length using custom !!! operator, increases size by 3
|
// change side length using custom !!! operator, increases size by 3
|
||||||
!!!mySquare
|
!!!mySquare
|
||||||
println(mySquare.sideLength) // 12
|
print(mySquare.sideLength) // 12
|
||||||
```
|
```
|
||||||
|
Loading…
Reference in New Issue
Block a user