27. Collections in Kotlin: List, Set, Map - immutable versions

🔍 Collections in Kotlin: Immutable Versions of List, Set, and Map

Hello, Kotlin developers! In this comprehensive guide, we'll dive deep into the world of immutable collections in Kotlin. Understanding how to work with immutable collections is crucial for writing clean, predictable, and thread-safe code.

📘 What are Immutable Collections?

Immutable collections are collections that cannot be modified after creation. Once an immutable collection is created, its content remains constant throughout the program's execution. This approach provides several benefits:

• Thread safety
• Predictable behavior
• Easier debugging
• Functional programming support

🧩 Immutable List in Kotlin

// Creating an immutable list
val immutableList = listOf(1, 2, 3, 4, 5)

// Attempting to modify will result in a compilation error
// immutableList.add(6) // NOT ALLOWED

// Creating an empty immutable list
val emptyList = emptyList()
    

Pro Tip: Use listOf() to create immutable lists in Kotlin.

🔒 Immutable Set Operations

// Creating an immutable set
val immutableSet = setOf("apple", "banana", "cherry")

// Set operations
val setA = setOf(1, 2, 3)
val setB = setOf(3, 4, 5)

val union = setA.union(setB)           // {1, 2, 3, 4, 5}
val intersection = setA.intersect(setB) // {3}
    

🗺️ Immutable Map Handling

// Creating an immutable map
val immutableMap = mapOf(
    "name" to "John",
    "age" to 30,
    "city" to "New York"
)

// Accessing map values
val name = immutableMap["name"]  // "John"
val keys = immutableMap.keys     // Set of keys
val values = immutableMap.values // Collection of values
    

💡 Practical Exercises

1. Create an immutable list of programming languages 2. Perform set operations with two different integer sets 3. Create a map of student names and their grades 4. Implement a function that works with immutable collections 5. Compare performance of immutable vs mutable collections

🚨 Common Pitfalls

• Trying to modify immutable collections
• Confusing immutability with unmodifiable collections
• Unnecessary conversions between mutable and immutable collections

🔬 Performance Considerations

Immutable collections have slight overhead compared to mutable ones. However, the benefits of immutability often outweigh the performance cost.

🎯 Conclusion

Immutable collections in Kotlin provide a robust way to manage data with predictability and safety. By understanding and utilizing these collections, you can write more functional and reliable code.

#Kotlin #Collections #Programming #Immutability

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