Merge 8e01273f3f into 88e5be6e4b

languages/javascript.js

@@ -95,9 +95,3 @@ arr.reduce(callback[, initialValue])                 // Apply a function against
 arr.reduceRight(callback[, initialValue])            // Apply a function against an accumulator and each value of the array (from right-to-left) as to reduce it to a single value.
 arr.some(callback[, initialValue])                   // Returns true if at least one element in this array satisfies the provided testing function.
 arr.values()                                         // Returns a new Array Iterator object that contains the values for each index in the array.
-
-// String methods
-String.charAt(index)                                 // Returns the character at the specified index in a string.
-String.indexOf(character)                            // Returns the index of the first occurrence of a specified value in a string.
-String.substring(starting_index, ending_index)       // Returns a new string that is a subset of the original string.
-String.substring(starting_index)                     // Returns a substring from starting index to last index of string.

mobile/kotlin.kt

@@ -0,0 +1,265 @@
+// Kotlin is a statically typed programming language for modern multiplatform applications.
+// https://kotlinlang.org/
+
+// Mutability
+var mutableString: String = "Adam"
+val immutableString: String = "Adam"
+val inferredString = "Adam"
+
+// Strings
+val name = "Adam"
+val greeting = "Hello, " + name
+val greetingTemplate = "Hello, $name"
+val interpolated = "Hello, ${name.toUpperCase()}"
+
+// Numbers
+val intNum = 10
+val doubleNum = 10.0
+val longNum = 10L
+val floatNum = 10.0F
+
+// Booleans
+val trueBoolean = true
+val falseBoolean = false
+val andCondition = trueBoolean && falseBoolean
+val orCondition = trueBoolean || falseBoolean
+
+// Static Fields
+class Person {
+    companion object {
+        val NAME_KEY = "name_key"
+    }
+}
+
+val key = Person.NAME_KEY
+
+
+// Nullable properties
+val cannotBeNull: String = null // Invalid
+val canBeNull: String? = null // Valid
+
+val cannotBeNull: Int = null // Invalid
+val canBeNull: Int? = null // Valid
+
+// Checking for null
+val name: String? = "Adam"
+
+if (name != null && name.length > 0) {
+    print("String length is ${name.length}")
+} else {
+    print("String is empty.")
+}
+
+// Safe Operator
+val nullableStringLength: Int? = nullableString?.length
+val nullableDepartmentHead: String? = person?.department?.head?.name
+
+// Elvis Operator
+val nonNullStringLength: Int = nullableString?.length ?: 0
+val nonNullDepartmentHead: String = person?.department?.head?.name ?: ""
+val nonNullDepartmentHead: String = person?.department?.head?.name.orEmpty()
+
+// Safe Casts
+// Will not throw ClassCastException
+val nullableCar: Car? = (input as? Car)
+
+/// Collections
+
+// Creation
+val numArray = arrayOf(1, 2, 3)
+val numList = listOf(1, 2, 3)
+val mutableNumList = mutableListOf(1, 2, 3)
+
+// Accessing
+val firstItem = numList[0]
+val firstItem = numList.first()
+val firstItem = numList.firstOrNull()
+
+// Maps
+val faceCards = mutableMapOf("Jack" to 11, "Queen" to 12, "King" to 13)
+val jackValue = faceCards["Jack"] // 11
+faceCards["Ace"] = 1
+
+// Mutability
+val immutableList = listOf(1, 2, 3)
+val mutableList = immutableList.toMutableList()
+
+val immutableMap = mapOf("Jack" to 11, "Queen" to 12, "King" to 13)
+val mutableMap = immutableMap.toMutableMap()
+
+// Iterating
+for (item in myList) {
+    print(item)
+}
+
+myList.forEach {
+    print(it)
+}
+
+myList.forEachIndexed { index, item -> 
+    print("Item at $index is: $item")
+}
+
+// Filtering & Searching
+val evenNumbers = numList.filter { it % 2 == 0 }
+val containsEven = numList.any { it % 2 == 0 }
+val containsNoEvens = numList.none { it % 2 == 0 }
+val containsNoEvens = numList.all { it % 2 == 1 }
+val firstEvenNumber: Int = numList.first { it % 2 == 0 }
+val firstEvenOrNull: Int? = numList.firstOrNull { it % 2 == 0 }
+// Note: it is the implicit name for a single parameter.
+
+/// Functions
+
+// Parameters & Return Types
+fun printName() {
+    print("Adam")
+}
+
+fun printName(person: Person) {
+    print(person.name)
+}
+
+fun getGreeting(person: Person): String {
+    return "Hello, ${person.name}"
+}
+
+fun getGreeting(person: Person): String = "Hello, ${person.name}"
+fun getGreeting(person: Person) = "Hello, ${person.name}"
+
+// Higher Order Functions
+fun callbackIfTrue(condition: Boolean, callback: () -> Unit) {
+    if (condition) {
+        callback()
+    }
+}
+
+callbackIfTrue(someBoolean) {
+    print("Condition was true")
+}
+
+/ Extension Functions
+fun Int.timesTwo(): Int {
+    return this * 2
+}
+
+val four = 2.timesTwo()
+
+// Default Parameters
+fun getGreeting(person: Person, intro: String = "Hello,") {
+    return "$intro ${person.name}"
+}
+
+// Returns "Hello, Adam"
+val hello = getGreeting(Person("Adam"))
+
+// Returns "Welcome, Adam"
+val welcome = getGreeting(Person("Adam"), "Welcome,")
+
+// Named Parameters
+class Person(val name: String = "", age: Int = 0)
+
+// All valid
+val person = Person()
+val person = Person("Adam", 100)
+val person = Person(name = "Adam", age = 100)
+val person = Person(age = 100)
+val person = Person(age = 100, name = "Adam")
+
+// Static Functions
+class Fragment(val args: Bundle) {
+    companion object {
+        fun newInstance(args: Bundle): Fragment {
+            return Fragment(args)
+        }
+    }
+}
+
+val fragment = Fragment.newInstance(args)
+// Companion Objects
+
+
+// Classes
+// Primary Constructor
+class Person(val name: String, val age: Int)
+val adam = Person("Adam", 100)
+
+// Secondary Constructors
+class Person(val name: String) {
+    private var age: Int? = null
+
+    constructor(name: String, age: Int) : this(name) {
+        this.age = age
+    }
+}
+
+// Above can be replaced with default params
+class Person(val name: String, val age: Int? = null)
+
+// Inheritance & Implementation
+open class Vehicle
+class Car : Vehicle()
+
+interface Runner {
+    fun run()
+}
+
+class Machine : Runner {
+    override fun run() {
+        // ...
+    }
+}
+// Control Flow
+If Statements
+if (someBoolean) {
+    doThing()
+} else {
+    doOtherThing()
+}
+
+// For Loops
+for (i in 0..10) { } // 1 - 10
+for (i in 0 until 10) // 1 - 9
+(0..10).forEach { }
+for (i in 0 until 10 step 2) // 0, 2, 4, 6, 8
+
+When Statements
+when (direction) {
+    NORTH -> {
+        print("North")
+    }
+    SOUTH -> print("South")
+    EAST, WEST -> print("East or West")
+    "N/A" -> print("Unavailable")
+    else -> print("Invalid Direction")
+}
+While Loops
+while (x > 0) {
+    x--
+}
+
+do {
+    x--
+} while (x > 0)
+
+// Destructuring Declarations
+// Objects & Lists
+val person = Person("Adam", 100)
+val (name, age) = person
+
+val pair = Pair(1, 2)
+val (first, second) = pair
+
+val coordinates = arrayOf(1, 2, 3)
+val (x, y, z) = coordinates
+
+// ComponentN Functions
+class Person(val name: String, val age: Int) {
+	operator fun component1(): String {
+		return name
+	}
+
+	operator fun component2(): Int {
+		return age
+	}
+}

mobile/swift.swift

@@ -0,0 +1,186 @@
+/********************************************************************************************
+ * Swift CHEATSHEET
+ * https://www.swift.org 
+ ********************************************************************************************/
+
+// Variables
+  var myInt = 1
+  var myExplicitInt: Int = 1 // explicit type
+  var x = 1, y = 2, z = 3 // declare multiple integers
+  myExplicitInt = 2 // set to another integer value
+
+// Constants
+  let myInt = 1
+  myInt = 2 // compile-time error!
+  
+// Strings
+  var myString = "a"
+  let myImmutableString = "c"
+  myString += "b" // ab
+  myString = myString + myImmutableString // abc
+  myImmutableString += "d" // compile-time error!
+
+  let count = 7
+  let message = "There are \(count) days in a week"
+  Logical Operators
+  var happy = true
+  var sad = !happy // logical NOT, sad = false
+  var everyoneHappy = happy && sad // logical AND, everyoneHappy = false
+  var someoneHappy = happy || sad // logical OR, someoneHappy = true
+
+// Printing
+  let name = "swift"
+  println("Hello")
+  println("My name is \(name)")
+  print("See you ")
+  print("later")
+  /*  Hello
+      My name is swift
+      See you later 
+  */
+
+// Arrays
+  var colors = ["red", "blue"]
+  var moreColors: String[] = ["orange", "purple"] // explicit type
+  colors.append("green") // [red, blue, green]
+  colors += "yellow" // [red, blue, green, yellow]
+  colors += moreColors // [red, blue, green, yellow, orange, purple]
+
+  var days = ["mon", "thu"]
+  var firstDay = days[0] // mon
+  days.insert("tue", atIndex: 1) // [mon, tue, thu]
+  days[2] = "wed" // [mon, tue, wed]
+  days.removeAtIndex(0) // [tue, wed]
+  Dictionaries
+  var days = ["mon": "monday", "tue": "tuseday"]
+  days["tue"] = "tuesday" // change the value for key "tue"
+  days["wed"] = "wednesday" // add a new key/value pair
+
+  var moreDays: Dictionary = ["thu": "thursday", "fri": "friday"]
+  moreDays["thu"] = nil // remove thu from the dictionary
+  moreDays.removeValueForKey("fri") // remove fri from the dictionary
+  Conditionals
+
+// IF STATEMENT
+  let happy = true
+  if happy {
+      println("We're Happy!")
+  } else {
+      println("We're Sad :('")
+}
+
+// We're Happy!
+
+  let speed = 28
+  if speed <= 0 {
+      println("Stationary")
+  } else if speed <= 30 {
+      println("Safe speed")
+  } else {
+      println("Too fast!")
+  }
+
+// Safe speed
+
+
+// SWITCH STATEMENT
+  let n = 2
+  switch n {
+  case 1:
+      println("It's 1!")
+  case 2...4:
+      println("It's between 2 and 4!")
+  case 5, 6:
+      println("It's 5 or 6")
+  default:
+      println("Its another number!")
+  }
+
+// It's between 2 and 4!
+  For Loops
+  for var index = 1; index < 3; ++index {
+    // loops with index taking values 1,2 
+  }
+  for index in 1..3 {
+    // loops with index taking values 1,2
+  }
+  for index in 1...3 { 
+    // loops with index taking values 1,2,3
+  }
+
+  let colors = ["red", "blue", "yellow"]
+  for color in colors {
+      println("Color: \(color)")
+  }
+  // Color: red
+  // Color: blue
+  // Color: yellow 
+
+  let days = ["mon": "monday", "tue": "tuesday"]
+  for (shortDay, longDay) in days {
+      println("\(shortDay) is short for \(longDay)")
+  }
+  // mon is short for monday
+  // tue is short for tuesday
+  While Loops
+  var count = 1
+  while count < 3 {
+      println("count is \(count)")
+      ++count
+  }
+  // count is 1
+  // count is 2
+
+  count = 1
+  while count < 1 {
+      println("count is \(count)")
+      ++count
+  }
+  //
+
+
+  count = 1
+  do {
+      println("count is \(count)")
+      ++count
+  } while count < 3
+  // count is 1
+  // count is 2
+
+count = 1
+do {
+    println("count is \(count)")
+    ++count
+} while count < 1
+
+// count is 1
+
+// Functions
+  func iAdd(a: Int, b: Int) -> Int {
+    return a + b
+  }
+  iAdd(2, 3) // returns 5
+
+  func eitherSide(n: Int) -> (nMinusOne: Int, nPlusOne: Int) {
+    return (n-1, n+1)
+  }
+  eitherSide(5) // returns the tuple (4,6)
+
+// Classes
+  class Counter {
+    var count: Int = 0 
+    func inc() { 
+      count++
+    }
+    func add(n: Int) {
+      count += n
+    }
+    func printCount() {
+      println("Count: \(count)")
+    }
+  }
+
+  var myCount = Counter()
+  myCount.inc()
+  myCount.add(2)
+  myCount.printCount() // Count: 3

tools/ubuntu.sh

@@ -21,7 +21,6 @@ cat /proc/<process_id>/maps   # Show the current virtual memory usage of a Linux
 ip r # Display ip of the server
 
 lsof -i :9000 # List process running on port 9000
-kill -9 $(lsof -t -i:PORT) # Kill the process running on whichever port specified
 
 journalctl -u minio.service -n 100 --no-pager # List last 100 logs for specific service