A guide to using the Map interface in Kotlin Co-host of the NinjaTalks podcast and community organizer at Google Developers Group. TreeHashMap is useful in certain scenarios for example.Sneh Pandya Follow Exploring the horizon with a knack for product management. They are not the only implementation of Map of course.

mutableMapOf() will gain you some bonus points in a data structure and algorithm interview though.

I wonder if mentioning the performance win for HashMap() vs. Results in > compareMapInits for 10 elements (repeated 1 times) - mutableMapOf: time taken: 3ms - HashMap: time taken: 0ms > compareMapInits for 100 elements (repeated 1 times) - mutableMapOf: time taken: 0ms - HashMap: time taken: 0ms > compareMapInits for 10000 elements (repeated 1 times) - mutableMapOf: time taken: 2ms - HashMap: time taken: 1ms > compareMapInits for 1000000 elements (repeated 1 times) - mutableMapOf: time taken: 107ms - HashMap: time taken: 119ms > compareMapInits for 10 elements (repeated 1000 times) mutableMapOf() total time taken: 5 ms HashMap() total time taken: 2 ms How often is HashMap() slower? 2/1000 > compareMapInits for 100 elements (repeated 1000 times) mutableMapOf() total time taken: 8 ms HashMap() total time taken: 10 ms How often is HashMap() slower? 10/1000 > compareMapInits for 10000 elements (repeated 1000 times) mutableMapOf() total time taken: 335 ms HashMap() total time taken: 225 ms How often is HashMap() slower? 206/1000 > compareMapInits for 1000000 elements (repeated 1000 times) mutableMapOf() total time taken: 81266 ms HashMap() total time taken: 69712 ms How often is HashMap() slower? 180/1000 can be a great choice IMO, as it explicitly states the importance of ordering here. Function we use to initialize Maps One time run fun main()

Mapof kotlin example