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[BCS]

Johnny wrote:
> Hello,
> 
> I've got a problem. I need to check if a hash key exists in a for loop like:
> 
> int [char[]] a;
> int [char[]] b;
> 
> a = { a => 1; b => 5; c=> 8 }
> b = { a => 5; b => 4; d => 3; f => 4 }
> 
> foreach (m; a.keys) {
>   if ( b[m] ) {
>    writefln("%s %s %s", m, a[m], b[m])
>   }
>   else {
>     writefln("%s %s", m, a[m])
>   }
> }
> 
> ... not "real" D but I hope you understand the code and what it should do.
> Thanks.
> 

What is the issue? That's about as good as anything I can think of. You 
might try this (but it's not much better)

foreach (k, v1; a) {
   if ( auto v2 = k in b )	// is this what your looking for?
    writefln("%s %s %s", k, v1, *v2)
   else
    writefln("%s %s", k, v1)
}