Kotlin InDepth Tutorial for beginners 2022

Kotlin InDepth Tutorial for beginners 2022

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  What’s in itfor you ? Introduction to Kotlin Variables in Kotlin String templates Array Loops in Kotlin Null safety Ranges Kotlin functions If-else and when
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  Introduction to Kotlin 1 2 3 Kotlinis a general-purpose, statically-typed programming language developed and released by Jet Brains in 2016. Kotlin is concise and more expressive than Java. It is fully interoperable with Java. Google also announced Kotlin as the first-class language for android development
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  Variables in Kotlin var val Thereare two types of variables in Kotlin var is the variable whose value can reassigned (mutable) var name = “Raj” name = “Sid“ // Value is reassigned println(name) OUTPUT: Sid
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  Variables in Kotlin var val Thereare two types of variables in Kotlin val is the variable whose value cannot be reassigned (immutable) val name = “Raj” name = “Sid” println(name) OUTPUT: error (Value can’t be reassigned)
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  Variables in Kotlin var val Thereare two types of variables in Kotlin var name = ”Mickey” // String val roll = 20 // integer println(name) println(roll) OUTPUT: Mickey 20
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  String templates The stringtemplates allows us to include the expressions, variable references inside the string. The references in a string start with $. We can easily add the variables in the string instead of concatenating them. var name1= “Ronny” var name2= “Mickey” println(“Both $name1 and $name2 are best friends”) println(“${name1.toUpperCase()} is older than $name2” ) OUTPUT: Both Ronny and Mickey are best friends RONNY is older than Mickey
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  If else andwhen statements In Kotlin language, the if else statements can also be used as expressions that means they can return a value. While using if-else as an expression, it is mandatory to use the else branch. For example: fun main() { val a = 205 val b = 195 val great= if (a > b) “$a is greater” else “$b is greater” println("$great") }
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  If else andwhen statements In Kotlin language, when statement is similar to switch statement in Java. It is used to select one code block out of multiple code blocks based on a conditional expression. For example: val tap = 4 val order = when (tap) { 1 -> “Pizza” 2 -> “Pasta” 3 -> “Fried rice” 4 -> “Wrap” 5 -> “Sandwich” 6 -> “Burger” else -> ”Invalid” } println(order)
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  Array Arrays are generallyused to store multiple values in a contiguous memory location in a single variable. In Kotlin you can easily create arrays. Var names= arrayOf( “Sid”, “Robby”, “Max”, “John”) For example: fun main() { var names= arrayOf( “Sid”, “Robby”, “Max”, “John”) for (n in names) { println(n) } }
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  Loops in Kotlin Loopsare generally used while working with arrays. 1) For loop for (n in numbers) { println(n) } } Here n is the variable, in is the operator and numbers is the array name. For example: fun main() { var numbers= arrayOf( 4, 2, 5, 12, 7) for (n in numbers) { println(n) } }
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  Loops in Kotlin Thewhile and do-while loop are similar to the loops in Java. 1) while loop: The while loop checks the condition and executes through the block of code as long as the specified condition is true. 2) do-while loop: The do-while loop executes the do block once before checking if the condition is true. For example: while loop while(condition) { body of the loop } do-while loop do { body of the loop } while(condition);
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  Null Safety Null safetyis a feature that solves the problem of null pointer exception. In Kotlin, you can make a null type variable. To create a variable or string which can hold a null value, we can simply define them by putting the question mark “?” in the end. Example: var name: String?=null
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  Ranges Range can bedefined as an interval from start to end. The expressions are created with operator(..). For example: for(i in 0..7) { println(i) } Output: 0 1 2 3 4 5 6 7 For example: for(i in 0..10 step 2 ) // 0 2 4 6… { print(i); } for(i in 7 downTo 2 ) // 7 6 5 4… { println(i); }
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  Kotlin Functions Functions whichare also known as methods are the block of code which runs whenever it is invoked. It is defined with the keyword fun Example: fun box() Function parameters are specified inside the parentheses. The type of parameter is specified after the name of the parameter. For example: fun box(num1: Int, num2: Int): Int{} Function name Parameters type Return type