[SciPy-user] truth testing new numpy arrays
Ryan Krauss
ryanlists at gmail.com
Tue Jan 31 10:23:53 EST 2006
I have a style question. With the old scipy/Numeric, when I had a
vector I wanted to be an optional variable in a function I would set
is default to "myvect=[]". Then when I wanted to test whether or not
the variable had been specified, I just checked "if myvect:". With
numpy arrays, this produces a message about ambiguous results for
testing arrays and says I should use myvect.any(). The problem is
that empty lists don't have an "any" method. I could set the optional
arrays explicitly to None or I could check if it" ==[]", but both of
these are slightly more fragile (if I accidentally pass an empty list
instead of None it would cause problems). I could also set the
optional array to "array([])" and always test "any()", but that is
more typing.
Is there a best way to handle optional arrays in function
specifications? (I am slightly addicted to Python's boolean testing
for empty objects.)
Ryan
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