[swift-evolution] Be able to initialise empty dict with array constrcutor

[Alexander Kempgen]

Yes. All of these variants are covered in the book The Swift Programming Language in some detail.

Alex

–––––
Alexander Kempgen
alex at kempgen.de

> Am 05.01.2016 um 14:42 schrieb James Campbell via swift-evolution <swift-evolution at swift.org>:
> 
> So the [Int]() is shorthand for Array<Int>()
> 
> On Tue, Jan 5, 2016 at 1:01 PM, Jeremy Pereira <jeremy.j.pereira at googlemail.com <mailto:jeremy.j.pereira at googlemail.com>> wrote:
> 
> > On 5 Jan 2016, at 12:51, James Campbell <james at supmenow.com <mailto:james at supmenow.com>> wrote:
> >
> > The problem for me is that is so counter intuitive I didn't even know you could do that.
> 
> The first one is a bit counter intuitive and I agree that
> 
> var distanceCache: [Int: Int] = []
> 
> might be an improvement, albeit not one I think many people would agree is worth doing. However, the second one is a natural extrapolation from the equivalent array syntax i.e.
> 
> var array = [Int]()
> var dictionary = [String: Int]()
> 
> >
> > On Tue, Jan 5, 2016 at 12:50 PM, Jeremy Pereira <jeremy.j.pereira at googlemail.com <mailto:jeremy.j.pereira at googlemail.com>> wrote:
> > I don’t understand what the problem is
> >
> > > On 5 Jan 2016, at 12:39, James Campbell via swift-evolution <swift-evolution at swift.org <mailto:swift-evolution at swift.org>> wrote:
> > >
> > > See this code:
> > > var distanceCache: [Int: Int] = Dictionary<Int, Int>()
> > >
> > > It is very long and tedious to write especially if what I am storing changes.
> > >
> > > I propose we be allowed to do the following:
> > > var distanceCache: [Int: Int] = []
> >
> > You can do
> >
> > var distanceCache: [Int: Int] = [:]
> >
> > Also
> >
> > var distanceCache2 = [Int: Int]()
> >
> >
> > > Perhaps this dictionary syntax is just confusing and it was a bad idea to make it the same as an array. Most languages use "{" so why did swift choose to share "[" with arrays and dictionaries.
> >
> > It’s not the same, you need the colons inside. I imagine that braces were discarded on the grounds that it would confuse the compiler with respect to closures, for example
> >
> > var myClosure = {} // is a variable of type () -> ()
> >
> >
> > >
> > > --
> > >  Wizard
> > > james at supmenow.com <mailto:james at supmenow.com>
> > > +44 7523 279 698 <tel:%2B44%207523%20279%20698>
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> >
> >
> >
> >
> > --
> >  Wizard
> > james at supmenow.com <mailto:james at supmenow.com>
> > +44 7523 279 698 <tel:%2B44%207523%20279%20698>
> 
> 
> 
> 
> -- 
>  Wizard
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> +44 7523 279 698
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