checking if a list contains at least 4 different items

[Sarah Smet]

Hello,

I'd like to check whether a list made of strings contains at least 4 differents items, or not:

for example

set my-list ["A" "B" "C" "A" "A" "B" "D"]

answer is true

set my-list ["A" "B" "C" "A" "A" "B" "B"]

answer is false

is there a command that does that easely ?

Thanks,

Sarah

[Charles Staelin]

A combination of remove-duplicates and length should do it.

if (length remove-duplicates my-list) >= 4 [ ... ]

Charles

[Jim Lyons]

No, but how about a one-liner?

to-report test4 [ #list ]

  report length remove-duplicates #list >= 4

end

to try-it

  print test4 ["A" "B" "C" "A" "A" "B" "D"] 

  ;; answer is true

  print test4 ["A" "B" "C" "A" "A" "B" "B"] 

  ;; answer is false

end

Jim

[Sarah Smet]

Thank you Jim and Charles for your answers. I did not know the "remove-duplicate" command and it fits my needs!

Best

Sarah