Is there a numpy equivalent of python's membership test (eg, "5 in [1,3,4,5]" returns True)? I'd like a quick way to test if a given number is in an array, without stepping through the elements individually. I realize this can be tricky with floats, but if there is such a thing for ints, that would be great. thanks Mark -- -- Mark Wendell
On Tue, May 5, 2009 at 10:37 PM, Mark Wendell <mark.wendell@gmail.com> wrote:
Is there a numpy equivalent of python's membership test (eg, "5 in [1,3,4,5]" returns True)? I'd like a quick way to test if a given number is in an array, without stepping through the elements individually. I realize this can be tricky with floats, but if there is such a thing for ints, that would be great.
import numpy as np (5==np.array([1,3,4,5])).any() True
np.setmember1d([5],[1,3,4,5]) array([ True], dtype=bool) np.setmember1d([3,5,6],[1,3,4,5]) array([ True, True, False], dtype=bool) np.setmember1d([3.1,5.3,6.],[1.,3.1,4.,5.3]) array([ True, True, False], dtype=bool)
setmember1d requires unique elements in both arrays, but there is a version for non-unique arrays in a trac ticket Josef
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Mark Wendell