Kotlin Practice Core

Part 1: Collections - List

01. Transformation Functions:

• map – Transform each element.
• flatMap – Flatten and transform collections.
• filter – Filter elements based on a condition.
• filterNot – Filter elements that don't meet a condition.
• filterNotNull – Filter out null values.
• mapNotNull – Transform non-null elements, remove nulls.
• distinct – Remove duplicate elements.
• sortedBy – Sort by a specific property.
• sortedDescending – Sort in descending order.
• sortedWith
• sortedWithDescending

02. Aggregation & Reduction:

• reduce – Combine elements into a single result.
• fold – Accumulate a value starting with an initial value.
• sumOf – Sum by a specific property.
• maxBy (maxOf) – Find the element with the max value by a property.
• minBy (minOf) – Find the element with the min value by a property.
• average – Calculate the average of numerical values.

03. Element Access:

• getOrNull – Safely get an element by index.
• first, firstOrNull – Get the first element or throw an exception.
• last, lastOrNull – Get the last element or throw an exception.
• find, findLast – Find the first element matching a condition.
• elementAtOrNull, elementAtOrElse – Get an element by index safely (return null if out of bounds).

04. Partitioning & Grouping:

• partition – Split collection into two based on a predicate.
• groupBy – Group elements by a key.

05. Checking Conditions:

• all – Check if all elements match a condition.
• any – Check if any element matches a condition.
• none – Check if no elements match a condition.
• contains – Check if a specific element is in the collection.

06. Set Operations:

• union – Combine two collections without duplicates.
• intersect – Get common elements between two collections.
• subtract – Get elements in one collection but not in another.

07. Creation & Conversion:

• toList – Convert to a list.
• toSet – Convert to a set.
• toMap – Convert a collection to a map.
• associate, associateWith, associateBy – Convert a collection to a map by a property.
• zip – Combine two collections into pairs.
• unzip – Separate a collection of pairs into two collections.
• plus – Add elements or another collection.
• minus – Remove elements or another collection.

08. Slicing & Windowing:

• take – Take the first N elements.
• drop – Skip the first N elements.
• chunked – Split a collection into chunks.
• windowed – Create a sliding window of elements.

09. Iteration:

• forEach – Iterate over each element.
• onEach – Perform an operation on each element and return the collection.
• iterator – Get an iterator for the collection.

10. Others:

• flatten – Flatten nested collections into a single collection.
• zipWithNext – Create pairs of consecutive elements.
• shuffled – Return a shuffled version of the collection.
• random – Return a random element from the collection.
• orEmpty – Return an empty list if the collection is null.
• requireNoNulls – Ensure no null elements, throw an exception otherwise.
• isEmpty – Check if the collection is empty.
• isNotEmpty – Check if the collection is not empty.
• count – Count the elements in a collection.

Part 2: Collections - Map

11. Map Creation & Modification

• mapOf – Create a read-only Map.
• mutableMapOf – Create a mutable Map.
• put – Add or replace a key-value pair in a mutable map.
• putAll – Add all key-value pairs from another map to the current map.
• remove – Remove an entry by its key.

12. Retrieving Data

• get – Get a value by its key.
• getOrDefault – Get a value by key, or return a default if the key is missing.
• getOrElse – Get a value or compute a default value if the key is absent.
• getValue – Get the value of the specified key or throw an exception if absent.

13. Iteration

• forEach – Iterate through key-value pairs.
• mapValues – Transform all values while keeping the keys.
• mapKeys – Transform all keys while keeping the values.

14. Filtering and Transforming

• filter – Filter entries based on key-value pairs.
• filterKeys – Filter only the keys.
• filterValues – Filter only the values.
• flatMap – Flatten a map into a sequence of entries.

15. Checking & Finding Entries

• containsKey – Check if the map contains a key.
• containsValue – Check if the map contains a value.
• any – Check if any entry satisfies a condition.
• all – Check if all entries satisfy a condition.
• none – Check if no entries satisfy a condition.
• firstNotNullOfOrNull - Finds the first entry that matches a given condition or null.

16. Other Map Utilities

• keys – Get a Set of all keys in the map.
• values – Get a Collection of all values.
• entries – Get a Set of map entries (key-value pairs).
• plus – Merge two maps.
• minus – Remove a key or multiple keys from a map.
• MutableMap: plusAssign, minusAssign

In progress...