Try like this:
>>> arr = np.array([100.10, 200.42, 4.14, 89.00, 34.55, 1.12])
>>> arr[[1,4,5]]
array([ 200.42, 34.55, 1.12])
And for multidimensional arrays:
>>> arr = np.arange(9).reshape(3,3)
>>> arr
array([[0, 1, 2],
[3, 4, 5],
[6, 7, 8]])
>>> arr[[0, 1, 1], [1, 0, 2]]
array([1, 3, 5])