Loop over keys and values of a hashtable

[Robert L.]

Edi Weitz wrote:

> > I'm trying to make a loop that runs over all pairs of keys/values of
> > a hashtable. My question is - will the code below always give the
> > key/value pairs that belong to each other. In some implementations
> > it does, but I'm asking whether it is reasonable to expect the
> > keys/values to be paird. My gut feeling is that it's not.
> >
> > For example the following code converting a hashtable to an assoc-list:
> >
> > (loop for key being the hash-keys of *hash*
> > for val being the hash-values of *hash* collect (cons key val))
>
> I think there's nothing in the standard that says the above code
> should do what you expect. Instead, use somthing like this:
>
> (loop for key being the hash-keys of *hash*
> using (hash-value val)
> collect (cons key val))

(define h (hash 'b 2 'c '3 'd 4))

(hash-map h cons)

===>
((c . 3) (b . 2) (d . 4))


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