CODEWITHSUNDEEP
sml
B. Williams
B. Williams

Reputation: 23

Return number of appearances in list

I am trying to create a SML function that takes lost of booleans and returns the number of times that "true" appears in the list.

fun truecount(lst) = foldl (fn (x,y) => if x=true then y+1) 0 lst;

I feel like I may be on the right path but I just can't quite seem to get it correct. If anyone sees how to do this please let me know!

Upvotes: 2

Views: 84

Answers (1)

Daniel McLaury
Daniel McLaury

Reputation: 4273

Well, what does your anonymous function

fn (x,y) => if x=true then y+1

return when x is not true?

What should it?

For that matter, what else do you need in an if ... then ... to get it to even compile?

Upvotes: 2

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