.filter()

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.

Syntax

str.filter(predicate)

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.

Example

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