Shift all indices in NumPy array

Question

I have the following numpy array:

x=np.array([0,1,2,3,4])
 

and want to create an array where the value in index 0 is in index 1, index 1 is in index 2, etc.

The output I want is:

y=np.array([0,0,1,2,3]).
 

How can I do this in a numPythonic way? Can anyone help?

Answer 1

You can use the following :

y = numpy.roll(x, 1)
y[0] = 0
 

or

y = numpy.r_[0, x[:-1]]