Published Oct 28, 2023
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The filter() function is used to filter elements from a collection based on a given predicate. It returns a new collection containing only elements that meet the given condition.



The filter() method only allows the selective characters based on the specified predicate which is passed as an argument.

  • The predicate is a lambda function that takes an element of the collection as an argument and returns a Boolean value. The filter() method will return a collection composed of all the elements that evaluated to true.


This example extracts all the alphabetic characters from str with the string.filter() method.

fun main(args: Array<String>) {
val str = "Hello, World!"
val result = str.filter({ it -> it.isLetter() })
println("Filtered String : " + result)

The above code will output:

Filtered String : HelloWorld

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