[Haskell-cafe] A simple beginner question

[Adam Smyczek]

Example:

data SampleType = A | B Int | C String | D -- .... etc.

sampleTypes = [A, B 5, C "test"] :: [SampleType]

How do I find for example element A in the sampleTypes list?
Do I have to create e.g.:

isA :: SampleType -> Bool
isA A = True
isA _ = False

for every constructor and use find?
It feels like this is not the quicker method.

Thanks,
Adam