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24List, Set, and Map
25Mutable vs. read-only collections
26What map does
27map: syntax and usage
28map: practical examples
29map: edge cases and pitfalls
30Common mistakes with map
31What filter does
32filter: syntax and usage
33filter: practical examples
34filter: edge cases and pitfalls
35Common mistakes with filter
36groupBy and associate
37Sequences: lazy collections
38Scope functions: let, run, apply, also, with
39Classes and primary constructors
40Properties and custom accessors
41Data classes
42Sealed classes and interfaces
43Object declarations and companions
44Inheritance and open
45Interfaces with default methods
46Visibility modifiers
47Delegation with by
48Generic classes and functions
49Variance: in and out
50Type aliases
51Inline functions and reified types

24List, Set, and Map
25Mutable vs. read-only collections
26What map does
27map: syntax and usage
28map: practical examples
29map: edge cases and pitfalls
30Common mistakes with map
31What filter does
32filter: syntax and usage
33filter: practical examples
34filter: edge cases and pitfalls
35Common mistakes with filter
36groupBy and associate
37Sequences: lazy collections
38Scope functions: let, run, apply, also, with
39Classes and primary constructors
40Properties and custom accessors
41Data classes
42Sealed classes and interfaces
43Object declarations and companions
44Inheritance and open
45Interfaces with default methods
46Visibility modifiers
47Delegation with by
48Generic classes and functions
49Variance: in and out
50Type aliases
51Inline functions and reified types

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Lesson 49 of 2,699·2. Collections and ClassesFree lesson

Variance: in and out

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