It is often supposed that functional programming is the use of higher-order functions (HOFs).
Example 1. Python
>>> map(lambda a: a + 1, [1, 2, 3]) [2, 3, 4]
Example 2. C#
csharp> new []{ 1, 2, 3 }.Select(a => a + 1); { 2, 3, 4 }
Example 3. Scala
scala> List(1, 2, 3) map (1+) res0: List[Int] = List(2, 3, 4)