[Tutor] Negative IF conditions

[Bob Gailer]

At 01:38 PM 2/11/2005, Kent Johnson wrote:
>Mark Brown wrote:
>>Hi,
>>I'm a newbie and was wondering which of these IF conditions is better 
>>structure:
>>    1. if not os.path.exists('filename'):
>
>I prefer the above.
>
>>    2. if os.path.exists('filename') == False:
>>They both work so if one preferred over the other?
>
>Note that in Python in general, 'not x' and 'x == False' are not 
>equivalent; 'not x' will be true for many more values than just False. For 
>example
>not 0
>not 0.0
>not []
>not {}
>
>are all True.

Oops. 0 and 0.0 do == False.

Bob Gailer
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