On Dec 23, 2009, at 6:04 , Nicolas Buduroi wrote:
> Hi, today I needed to use the map function on multiple collections
> which didn't had all the same length. In this case, it returns a
> sequence of the size of smallest one. But the problem I was facing was
> required to map until the end of the longest, padding the smaller ones
> with a default value. I came up with this:
No code but an idea, calling length on the collection might force them to be
itterated entirely why not define something like a lazy seq that takes:
1) the sequence to extend
2) the default value
3) a number of other sets
As long as any of the lists is not epty return either first or the default
value, this saves iterating through all lists, and is lazy :)
A quick not tested and proably horribl wrong example:
(defn extend-list [main-list default & other-lists]
(if (some #(not (empty? %)) other-lists)
(if
(cons
(empty? main-list) default (first main-list)) (apply extend-list (next
main-list) default (map next other-lists)))))
(this is not tested and just an idea, sorry short in time!
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