Seq count number of elements

Question

What is the easiest way to count the number of elements in a sequence in F#?

score 54 · Accepted Answer · edited May 06 '21 at 17:35

54

Returns the length of the sequence

edited May 06 '21 at 17:35

aloisdg

answered Jul 06 '10 at 18:23

Yin Zhu

3

duh... all along I was looking for Count o r Total Elements! Thanks Yin – Mark Pearl Jul 06 '10 at 18:27

score 8 · Answer 2 · answered Jul 06 '10 at 18:24

8

open System.Linq

mySeq.Count()

answered Jul 06 '10 at 18:24

Mark H

One advantage of this solution is that you can filter inside a Count(). For example, `x |> Seq.filter (System.Char.IsLetter) |> Seq.length` could be write `(x : string).Count (fun x -> Char.IsLetter(x))` – aloisdg Jan 27 '17 at 11:50
Then you could also use Seq.countBy, or not? – Anytoe Mar 26 '17 at 12:19

score 6 · Answer 3 · answered Jul 06 '10 at 18:36

6

FYI, if you search the library docs for Seq for "-> int" you'll find this rather quickly.

answered Jul 06 '10 at 18:36

Brian

score 5 · Answer 4 · answered Jul 06 '10 at 18:32

5

you can use Seq.length

answered Jul 06 '10 at 18:32

Ankur Gurha

4 Answers4