Tuples in F#
Pair values without ceremony; patterns take them apart.
// Tuples pair values without ceremony; patterns take them apart.
let coordinates = (52.74, 0.39)
let lat, lon = coordinates
printfn "Apiary at %.2f N, %.2f E" lat lon
// fst and snd read pairs; functions can return them.
let weighAndCount () = (31.4, 18)
let weight, frames = weighAndCount ()
printfn "%.1f kg over %d frames" weight frames
// Underscore discards what you do not need.
let _, framesOnly = weighAndCount ()
printfn "Frames alone: %d" framesOnly
printfn "First of pair: %.2f" (fst coordinates)How it works
let lat, lon = coordinatesdestructures in one line.- Functions return tuples for free multiple results.
fst,snd, and_cover the quick accesses.
Keywords and builtins used here
let
The run, in numbers
- Lines
- 14
- Characters to type
- 510
- Tokens
- 71
- Three-star pace
- 70 tpm
At the three-star pace of 70 tokens a minute, this run takes about 61 seconds.
Step 3 of 3 in Types, step 15 of 27 in Language basics.