[Haskell-beginners] Mixed division

[Lawrence Bottorff]

This works

myAvg :: [Float] -> Float
myAvg [] = 0.0
myAvg xs = (foldr (+) 0.0 xs) / (fromIntegral (length xs) :: Float)

but is there a simpler way to "cast" the value of (length xs)?

On Fri, Feb 5, 2021 at 12:29 PM Ut Primum <utprimum at gmail.com> wrote:

> Hi,
> when you write 3 Haskell sees it as a "num" while the type of the length
> [1,2,3] is "int". So 3 and length [1,2,3] have not the same type.
>
> Il ven 5 feb 2021, 19:23 Lawrence Bottorff <borgauf at gmail.com> ha scritto:
>
>> I can divide a float by an integer
>>
>> >  2.4 / 3
>> 0.7999999999999999
>>
>> but why can I not do this?
>>
>> < 2.4 / (length [1,2,3])
>> <interactive>:288:1-22: error:
>>     * No instance for (Fractional Int) arising from a use of `/'
>>     * In the expression: 2.4 / (length [1, 2, 3])
>>
>> LB
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