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How to clear all elements from a HashSet in Kotlin

How to clear all elements from a HashSet in Kotlin.

Here's a step-by-step tutorial on how to clear all elements from a HashSet in Kotlin:

Step 1: Create a HashSet​

First, let's create a HashSet and add some elements to it. In this example, we'll create a HashSet of strings.

val hashSet = HashSet<String>()
hashSet.add("Apple")
hashSet.add("Banana")
hashSet.add("Orange")

Step 2: Clear the HashSet​

To clear all elements from the HashSet, we can use the clear() function. This function removes all elements from the HashSet.

hashSet.clear()

After calling the clear() function, the HashSet will be empty.

Step 3: Check if the HashSet is empty​

To verify that the HashSet is empty, we can use the isEmpty() function. This function returns true if the HashSet is empty, and false otherwise.

val isEmpty = hashSet.isEmpty()
println("Is the HashSet empty? $isEmpty")

The output will be: Is the HashSet empty? true, indicating that the HashSet is empty.

Step 4: Print the HashSet​

Let's print the HashSet to verify that it is indeed empty.

println("HashSet after clearing all elements: $hashSet")

The output will be an empty set: {}.

Step 5: Alternative method using reassignment​

Another way to clear a HashSet is by reassigning a new empty HashSet to the existing variable.

hashSet = HashSet()

This will create a new empty HashSet and assign it to the variable, effectively clearing all elements from the HashSet.

Step 6: Verify the HashSet is empty​

Just like in Step 3, you can use the isEmpty() function to check if the HashSet is empty after reassignment.

val isEmpty = hashSet.isEmpty()
println("Is the HashSet empty? $isEmpty")

The output will again be: Is the HashSet empty? true, confirming that the HashSet is now empty.

That's it! You have successfully cleared all elements from a HashSet in Kotlin using either the clear() function or reassigning a new empty HashSet.