(Numpy) Index list to boolean array

Question

Input:

1. array length (Integer)
2. indexes (Set or List)

Output:

A boolean numpy array that has a value 1 for the indexes 0 for the others.

---

Example:

Input: array_length=10, indexes={2,5,6}

Output:

[0,0,1,0,0,1,1,0,0,0]

Here is a my simple implementation:

def indexes2booleanvec(size, indexes):
    v = numpy.zeros(size)
    for index in indexes:
        v[index] = 1.0
    return v

Is there more elegant way to implement this?

Answer 1

One way is to avoid the loop

In [7]: fill = np.zeros(array_length)     #  array_length = 10

In [8]: fill[indexes] = 1                 #  indexes = [2,5,6]

In [9]: fill
Out[9]: array([ 0.,  0.,  1.,  0.,  0.,  1.,  1.,  0.,  0.,  0.])

Answer 2

Another way to do it (in one line):

np.isin(np.arange(array_length), indexes)

However this is slower than Zero's solution.