[SciPy-user] truth testing new numpy arrays

Paul Ray Paul.Ray at nrl.navy.mil
Tue Jan 31 13:10:03 CST 2006

On Jan 31, 2006, at 10:43 AM, Travis Oliphant wrote:

> I typically use None for optional array arguments.
> But, you could do what your doing and test
> if any(myvect):
>     <do something>
> else:
>     <do something else>
> But, I think the None test is less prone to error.

Assuming you use None for unset optional arguments, how do  you do  
the test?

if myvect:
	<do something>
doesn't work because it is ambiguous if myvect isn't none.

if myvect.any():
	<do something>
doesn't work because None doesn't have an any() method

So, do you use:
if any(myvect):
	<do something>
if myvect is not None:
	<do something>

-- Paul

Dr. Paul S. Ray              E-mail: Paul.Ray at nrl.navy.mil
Naval Research Laboratory    WWW   : http://xweb.nrl.navy.mil/ 
Code 7655                    Phone : (202) 404-1619
Washington, DC 20375         AIM   : NRLPSR

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