Property & Method

• Kotlin mutable & immutable variable – val vs var
• Java Static Method equivalent in Kotlin
• Lazy Initialization Example
• Delegated Property – Observable Property

Operator

• Kotlin Equality – Difference between “===” vs “==”

Function

• Return Function from Function

String

• Split String example
• Convert comma-separated String into List & List into one String
• Convert String to Int
• Convert String to Long

Comparation

• Compare Objects with Comparable Example

JSON

• Convert Object to/from JSON with Jackson 2.x
• Convert Object to/from JSON with Gson

Collections

List

• Kotlin List & Mutable List tutorial with examples
• Kotlin Distinct() methods of List collection
• Kotlin List methods – max() maxBy() maxWith()
• Kotlin List methods – min() minBy() minWith()
• Kotlin List reduce(), reduceIndexed(), reduceRight(), reduceRightIndexed() methods example
• Kotlin filter List example
• Kotlin transform List with map() methods example
• Kotlin Flatten List – Problem & Solution

Map

• Kotlin Map methods – maxBy() maxWith()
• Kotlin Map methods – minBy() minWith()
• Kotlin convert Map to SortedMap
• Kotlin Map collection with flatMap(), flatMapTo() methods
• Kotlin – filter() map examples
• Kotlin Map collection – map() methods

Array

• Kotlin Flatten Array
• Kotlin Array find the Largest Element – max() maxBy() maxWith() methods
• Kotlin Array find the Smallest Element – min() minBy() minWith() methods
• Kotlin – average() function with Kotlin Array – List examples
• Kotlin Array sort(), sortBy(), sortWith()

Others

• Sort List of Objects with Comparator Example
• Sort List of Objects with Comparable Example
• Convert comma-separated String into List & List into one String
• Kotlin sum() and sumBy() method for List, Map of Objects example
• Kotlin Partition method – split List, Map of Objects example
• Kotlin Fold Example
• Convert Kotlin Map to List
• Convert Kotlin List to Map
• Kotlin forEach & forEachIndexed method on Array, List, Map collection
• Kotlin Loop: for loop + while loop + break & continue example
• Kotlin methods – any(), none(), all(), contains()
• Kotlin collection methods – groupBy(), sumByDouble(), mapValues(), toSortedMap() example
• Kotlin onEach() vs forEach() example

Files – I/O

• How to read File in Kotlin
• How to write to file in Kotlin
• Kotlin get File Name example
• How to read/write CSV file in Kotlin
• How to read/write CSV file with Apache Commons CSV
• How to read/write CSV file with OpenCSV
• How to read/write Excel file with Apache POI
• How to read/write QR Code with ZXing

Kotlin DateTime

• Kotlin – Get Current Date/Time
• Kotlin Convert String to DateTime
• Kotlin DateTime – get Today, Tomorrow, Yesterday with LocalDate, ZonedDateTime
• Kotlin DateTime API examples

Sample for Practice

• Sort List of Objects with Comparator Example
• Sort List of Objects with Comparable Example
• Kotlin Comparable Binary Search for Object List
• Kotlin Comparator Binary Search for Object List
• Sort Object List with Kotlin Selector function – crossinline selector: (T) -> R?
• Binary Search for Object List with Comparison function – comparison: (T) -> Int
• Binary Search for Object List with Selector function – crossinline selector: (T) -> K?
• Kotin – toString() – convert Kotlin Data Class Object to String
• Kotlin – Encode (Decode) File/Image to Base64