Arithmetic with Boolean values

Paul Rubin no.email at nospam.invalid
Sun Aug 12 02:54:40 CEST 2012


John Ladasky <john_ladasky at sbcglobal.net> writes:
> I have gotten used to switching back and forth between Boolean algebra
> and numerical values.  Python generally makes this quite easy. 

Generally ugly though, at least to my tastes.  "Explicit is better
than implicit" as the saying goes.

> If the length of the list L is odd, I want to process it once.  If
> len(L) is even, I want to process it twice....
>   for x in range(1 + not(len(L) % 2)):

If you really have to do something like that, I'd say

   for x in range(1 + (len(L) & 1)):

or

   for x in range(2 - len(L) % 2): 

are simpler and avoid those bogus bool conversions.  I'd prefer to
just say the intention:

   for x in range(1 if len(L)%2==1 else 2):

> This provoked a SyntaxError. 

"not" is a syntactic keyword and "1 + not" is syntactically invalid.
You could write "1 + (not ...)" as you discovered, but really, it's
hackish.



More information about the Python-list mailing list