Add single element to array in numpy

I have a numpy array containing:

[1, 2, 3]

I want to create an array containing:

[1, 2, 3, 1]

That is, I want to add the first element on to the end of the array.

I have tried the obvious:

np.concatenate((a, a[0]))

But I get an error saying ValueError: arrays must have same number of dimensions

I don’t understand this – the arrays are both just 1d arrays.

Answer

append() creates a new array which can be the old array with the appended element.

I think it’s more normal to use the proper method for adding an element:

a = numpy.append(a, a[0])