[swift-users] Modulo operation in Swift?

[Rick Mann]

Why is % not available for floating point numbers?

> On Nov 9, 2017, at 04:51 , Martin R via swift-users <swift-users at swift.org> wrote:
> 
> There was a discussion in swift-evolution, starting at
> 
>  https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160516/018521.html
> 
> about adding a "true modulo" operator to the standard library. There were different opinions whether
> 
> - such a thing needs to be in the standard library at all, and if yes:
> - if it should be an operator or function,
> - how it should be named.
> 
> As far as I know, nothing happened until now. The above posting contains a possible (Swift 3) implementation. In Swift 4 that would be
> 
>    infix operator %%: MultiplicationPrecedence
> 
>    func %%<T: BinaryInteger>(lhs: T, rhs: T) -> T {
>        return (lhs % rhs + rhs) % rhs
>    }
> 
> I would probably do (as an operator or as a function)
> 
>    func %%<T: BinaryInteger>(lhs: T, rhs: T) -> T {
>        let rem = lhs % rhs // -rhs <= rem <= rhs
>        return rem >= 0 ? rem : rem + rhs
>    }
> 
> with one division instead of two.
> 
> Regards, Martin
> 
>> Am 09.11.2017 um 12:43 schrieb Jens Persson via swift-users <swift-users at swift.org>:
>> 
>> Hi all!
>> Is there a modulo operation/function in Swift? I want the "true" mathematical modulo (as % in Python), and not remainder (as % in Swift).
>> 
>> Do I have to implement this basic mathematical function myself and if so what is the best way to write it (it will be heavily used so I want it to be as fast as possible)?
>> 
>> /Jens
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-- 
Rick Mann
rmann at latencyzero.com