How to check f# if collection is empty?


cute

How can i check if the collection is empty, if the collection has an empty collection, i have implemented the following code, then i should get the value true else false, eg: [1; 2; []] the result of this collection should be true and This should result in an error if the set is [1; 2; 3] since there are no empty sets in it. The following is the code that gives me an error:

let rec isEmpty S =
   match S with
  |[] -> true
  |_ -> false
  |e::rest -> ([]=e) || (isEmpty [] rest)
Robert Nelson

Unfortunately, for your use case, F# is a lot more "strongly typed" than you would like here.

In F#, something like [1; 2; 3] is a list of ints, a list of ints will not accept something like [1; 2; []].

Maybe you can try to define a new (recursive) data type for your problem.

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