[nvda-addons] Re: Tone Master addon now on github
- From: James Scholes <james@xxxxxxxxxxxxx>
- To: nvda-addons@xxxxxxxxxxxxx
- Date: Mon, 18 Jul 2016 10:47:52 +0100
Joseph Lee wrote:
* Loaded == None versus Lloaded is None versus not loaded: it's up to you.
Usually "loaded is None" might be a bit more clear.
The semantic meaning of all three snipets of code is completely different.
1. If you're checking whether an object is None, you should use is.
None is a singleton, and equality comparisons with singleton objects are
discouraged. You wouldn't write, for example:
if x > None
So it doesn't make much sense to use == either. Also using is is
slightly faster when checking for None objects.
2. Using not should probably be limited to boolean logic only. If you
have a value that can be None, your code should make that clear. If
your value will always be initialised to either True or False, using:
if loaded
and
if not loaded:
is fine.
--
James Scholes
http://twitter.com/JamesScholes
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