What auxiliary functions do you know or have used in…

Lambda expressions: Shorten code for small handler functions, such as clicks or callbacks.

Extension Functions (Kotlin): Add new functions to existing classes without inheritance, improving readability and convenience.

fun String.isPalindrome(): Boolean {
    // Checks if the string is a palindrome
    return this == this.reversed()
}

Inline Functions (Kotlin): Embed the function body at the call site, reducing overhead of creating function objects, especially useful with lambdas.

inline fun measureExecutionTime(block: () -> Unit) {
    // Measures the execution time of a code block
    val startTime = System.currentTimeMillis()
    block()
    val endTime = System.currentTimeMillis()
    println("Execution time: ${endTime - startTime} ms")
}

Data Classes (Kotlin): Automatically generate equals(), hashCode(), toString(), copy(), which is convenient for data storage.
```
data class User(val name: String, val age: Int)
```
Sealed Classes (Kotlin): Represent a limited hierarchy of classes, useful for modeling states or events, especially in combination with the when operator.

Generics: Allow creating reusable components that work with different data types.

public class Box<T> {
    // Generic class for storing any data type
    private T data;

    public void setData(T data) {
        this.data = data;
    }

    public T getData() {
        return data;
    }
}

Operations with collections (map, filter, reduce, etc.): Functional methods for processing data collections.

val numbers = listOf(1, 2, 3, 4, 5)
val squaredEvenNumbers = numbers
    .filter { it % 2 == 0 } // Filter even numbers
    .map { it * it }      // Square the numbers

Resource getters (Kotlin): For obtaining strings, colors, sizes, etc., from resources.

val appName = context.getString(R.string.app_name)
val primaryColor = ContextCompat.getColor(context, R.color.colorPrimary)

Nullable types and safe calls (Kotlin): Reduce NullPointerException occurrences.

val name: String? = null
val length = name?.length ?: 0 // Safe call and Elvis operator

What auxiliary functions do you know or have used in your experience?