On 30Dec2016 15:17, Deborah Swanson <pyt...@deborahswanson.net> wrote:
        Ever consider using conjunctions?

        if len(l1[st]) and not len(l2[st]):
                #0 is considered a false -- no need to test for "==0"
                #non-0 is considered true -- no need to test for ">0"
                #copy l1 to l2
        elif not len(l1[st]) and len(l2[st]):
                #copy l2 to l1
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        Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfr...@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

That's a neat shortcut, len(a) instead of len(a)!= 0.  Thanks!

Also, for almost every python collection (lists, tuples, sets etc), python boolean logic tests __nonzero__, which works off len() by default.

So:

 if a:
   # a is not empty: len(a) > 0
 else:
   # a is empty: len(a) == 0

I find this far more readable, presuming the reader knows that "empty" things test as false. Of course, you need to ensure that any "collection"-ish classes you use or write have this property, but the builtin ones do.

Cheers,
Cameron Simpson <c...@zip.com.au>
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