问题
My question is very simple, suppose that I have an array like
array = np.array([1, 2, 3, 4])
and I'd like to get an array like
[1, 0.5, 0.3333333, 0.25]
However, if you write something like
1/array
or
np.divide(1.0, array)
it won't work.
The only way I've found so far is to write something like:
print np.divide(np.ones_like(array)*1.0, array)
But I'm absolutely certains that there is a better way to do that. Does anyone have any idea?
回答1:
1 / array makes an integer division and returns array([1, 0, 0, 0]).
1. / array will cast the array to float and do the trick:
>>> array = np.array([1, 2, 3, 4])
>>> 1. / array
array([ 1. , 0.5 , 0.33333333, 0.25 ])
回答2:
I tried :
inverse=1./array
and that seemed to work... The reason
1/array
doesn't work is because your array is integers and 1/<array_of_integers> does integer division.
回答3:
Other possible ways to get the reciprocal of each element of an array of integers:
array = np.array([1, 2, 3, 4])
Using numpy's reciprocal:
inv = np.reciprocal(array.astype(np.float32))
Cast:
inv = 1/(array.astype(np.float32))
来源：https://stackoverflow.com/questions/10384757/numpy-array-element-wise-division-1-x