checking if two things do not equal None
roy at panix.com
Sun Mar 30 14:21:25 CEST 2014
In article <5337b4e4$0$29994$c3e8da3$5496439d at news.astraweb.com>,
Steven D'Aprano <steve+comp.lang.python at pearwood.info> wrote:
> I think Johannes got it right: boolean logic is easier to reason about
> when there is a minimum of "not"s.
I used to do a lot of digital logic design. In certain logic families,
it's easier to build a NAND gate than an AND gate (and similarly, NOR is
easier than OR). This leads to lots of inverted logic. Adding to the
confusion, many designs would use "active low" logic, which means a 1
was represented by a low voltage, and a 0 by a high voltage. So, you
quickly end up with gibberish like, "not active low clear nand not
active low enable clock". I'm glad I don't do that stuff any more.
More information about the Python-list