How to add a dimension to a numpy array in Python

Question

I have an array that is size (214, 144). I need it to be (214,144,1) is there a way to do this easily in Python? Basically the dimensions are supposed to be (Days, Times, Statio

Answer 1

1) To add a dimension to an array a of arbitrary dimensionality:

b = numpy.reshape (a, list (numpy.shape (a)) + [1])

Explanation:

You get the shape of a, turn it into a list, concatenate 1 to that list, and use that list as the new shape in a reshape operation.

2) To specify subdivisions of the dimensions, and have the size of the last dimension calculated automatically, use -1 for the size of the last dimension. e.g.:

b = numpy.reshape(a, [numpy.size(a,0)/2, numpy.size(a,1)/2, -1])

The shape of b in this case will be [214,144,4].

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(obviously you could combine the two approaches if necessary):

b = numpy.reshape (a, numpy.append (numpy.array (numpy.shape (a))/2, -1))