kotlin filternot

The filterNot function in Kotlin is used to filter a collection based on a provided predicate. It returns a new list containing all the elements for which the predicate returns false. Here is an explanation of each step involved in using the filterNot function:

  1. Import the required packages: Make sure to import the necessary packages to use the filterNot function. You can import it using the following statement:

kotlin import kotlin.collections.filterNot

  1. Create a collection: Create a collection of elements that you want to filter. This can be a list, set, or any other type of collection. For example, let's create a list of numbers:

kotlin val numbers = listOf(1, 2, 3, 4, 5)

  1. Define the predicate: Define a predicate that specifies the condition for filtering the elements. The predicate is a lambda expression that takes an element as its argument and returns a Boolean value indicating whether the element should be included in the filtered list. For example, let's define a predicate that filters out even numbers:

kotlin val predicate: (Int) -> Boolean = { number -> number % 2 != 0 }

In this case, the predicate checks if the number is not divisible by 2, which means it is an odd number.

  1. Use the filterNot function: Apply the filterNot function on the collection and pass the predicate as an argument. The function will return a new list containing all the elements for which the predicate returns false. For example, let's filter the numbers list using the defined predicate:

kotlin val filteredNumbers = numbers.filterNot(predicate)

The filteredNumbers list will contain all the odd numbers from the numbers list.

  1. Access the filtered elements: You can now access the filtered elements in the filteredNumbers list and perform further operations on them. For example, you can print the filtered numbers:

kotlin for (number in filteredNumbers) { println(number) }

This will print the odd numbers from the numbers list.

That's it! You have now learned how to use the filterNot function in Kotlin to filter a collection based on a predicate.