Python Numpy Structured Array (recarray) assigning values into slices
When you say test['ifAction'] you get a view of the data.When you say test[['ifAction','ifDocu']] you are using fancy-indexing and thus get a copy of the data. The copy doesn't help you since modifying the copy leaves the original data unchanged.
So a way around this is to assign values to test['ifAction'] and test['ifDocu'] individually:
test['ifAction'][0]=1test['ifDocu'][0]=1For example:
import numpy as nptest=np.rec.array([(0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0), (0, 0, 0)], dtype=[('ifAction', '|i1'), ('ifDocu', '|i1'), ('ifComedy', '|i1')])print(test[['ifAction','ifDocu']])# [(0, 0) (0, 0) (0, 0) (0, 0) (0, 0) (0, 0) (0, 0) (0, 0) (0, 0) (0, 0)]test['ifAction'][0]=1test['ifDocu'][0]=1print(test[['ifAction','ifDocu']][0])# (1, 1)test['ifAction'][0:10]=1test['ifDocu'][0:10]=1print(test[['ifAction','ifDocu']])# [(1, 1) (1, 1) (1, 1) (1, 1) (1, 1) (1, 1) (1, 1) (1, 1) (1, 1) (1, 1)]For a deeper look under the hood, see this post by Robert Kern .