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Xref: csiph.com comp.lang.python:57527

On 10/25/13 7:55 AM, Mark Janssen wrote:
> On Thu, Oct 24, 2013 at 8:40 PM, Mark Lawrence <breamoreboy@yahoo.co.uk> wrote:
>> On 22/10/2013 18:37, Oscar Benjamin wrote:
>>> OTOH why in particular would you want to initialise them with zeros? I
>>> often initialise arrays to nan which is useful for debugging.
> Is this some kind of joke?  What has this list become?
>

It's a useful debugging technique to initialize memory to distinctive 
values that should never occur in real data.  Perhaps it better to say, 
"pre-initialize".  If the program is working correctly, then that data 
will be written over with actual initial values, and you'll never see 
the distinctive values.  But if your program does encounter one of those 
values, it's clear that there's a bug that needs to be fixed.  
Additionally, if you have a number of different distinctive values, then 
the actual value encountered provides a clue as to what might have gone 
wrong.

In an array of floats, initializing to NaN would be very useful, since 
NaNs propagate through calculations, or raise exceptions.

--Ned.