On 4/11/17 11:48 PM, mirone wrote:
Hello everyone! If I have a list A : ["x", "y", "z"] and a list B: ["f", "g"]. Here is my question: What's the simplest way to replace "z" in the list A by list B, and get ["x", "y", "f", "g"] ?
f _ _ = ["x","y","f","g"] That's a joke, but it really isn't clear what the question means. One possibility is f a b = init a ++ b f [1,2,3,4,5] [9,8,7] => [1,2,3,4,9,8,7] If you mean that you want to replace "z" by ... wherever it occurs, something like -- (f needle straws haystack) replaces each occurrence of needle as -- an element of haystack with the elements of straws. f :: Eq t => t -> [t] -> ([t] -> [t]) f needle straws = concatMap (\straw -> if straw == needle then straws else [straw]) f "z" ["f","g"] ["x","z","y","z"] => ["x","f","g","y","f","g"] Your question admits of too many generalisations for us to be really helpful.