I have 2 numpy arrays:
arr_a = array(['1m_nd', '2m_nd', '1m_4wk'],
dtype='<U15')
arr_b = array([0, 1, 1])
I want to select elements from arr_a based on arr_b. I am doing this:
arr_a[arr_b], but I get this as result:
array(['1m_nd', '2m_nd', '2m_nd'],
dtype='<U15')
instead of:
array(['2m_nd', '1m_4wk'],
dtype='<U15')
How do i fix this?
You need to pass it a boolean array, for example:
>>> arr_a[arr_b>0]
array(['2m_nd', '1m_4wk'],
dtype='<U15')
Given arr_a and arr_b, Running the following will give the boolean array for each of the elements in arr_b whose value is 1 => True and 0 => False . Correspondingly the boolean values are checked with the index value in arr_a. Here is the line of code you'd need.
>>> arr_a[arr_b == 1]
array([u'2m_nd', u'1m_4wk'],
dtype='<U15')
