Arrays in F#

In F# we declare an array using square brackets, pipes and semi-colons as follows. Here’s how to declare an integer array with some elements:

let myArray = [|1;3;5;7;9|]

int [] = [|1; 3; 5; 7; 9|]

We can easily access individual members of the array using the .[] notation as follows:

let secondElement = myArray.[1]

secondElement will be 3. Indexing is 0-based just like in all popular programming languages, so the index 1 is the second element in the array.

The indexer can be used to extract a specific element from an array:

let arrayRange = myArray.[1..3]

arrayRange : int [] = [|3; 5; 7|]

Here’s how to extract all elements from the 2nd position until the last. We simply ignore the end index:

let arrayRange = myArray.[1..]

arrayRange : int [] = [|3; 5; 7; 9|]

We can similarly ignore the start index:

let arrayRange = myArray.[..3]

arrayRange : int [] = [|1; 3; 5; 7|]

View all F# related articles here.