[Numpy-discussion] (arange(2, typecode=Complex) % 2).typecode()

Charles G Waldman cgw at fnal.gov
Fri Jun 2 11:41:51 CDT 2000


Jean-Bernard Addor writes:
 > Hey again!
 > 
 > Why is (arange(2, typecode=Complex) % 2).typecode() object and not
 > complex?

Looks like a bug to me!

>>> x=arange(2, typecode=Complex) 
>>> x
array([ 0.+0.j,  1.+0.j])
>>> x+10
array([ 10.+0.j,  11.+0.j])
>>> x*10
array([  0.+0.j,  10.+0.j])
>>> x/10
array([ 0. +0.j,  0.1+0.j])
>>> x%10
array([0j , (1+0j) ],'O')

I don't see (offhand) why other operations leave the array as complex,
and "%" causes it to be an 'O'.  Presumably complex arrays lack the
"mod" method and are getting promoted to Object.  However, for float
and double arrays you get the expected behavior:

>>> x=arange(2, typecode=Float) 
>>> x%10
array([ 0.,  1.])





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