How can I sort a numpy array to find a minimum coordinate?

Question

I'm relatively new at numpy and I want to sort an array to find a point which has the lowest x and y values.

How would I sort the following array in numpy, such that it sorts the first column in ascending order, which are the x coordinate values, and then the second column, which are the y coordinates?

[[0.1, 0.2]
[0.5, 0.1]
[0.3, 0.9]
[0.7, 1.0]
[0.1, 0.3]
[0.2, 0.3]]

I have seen answers regarding numpy.sort, but I did not understand what the meaning of sorting by an axis was.

Answer 1

You can use numpy.lexsort . This performs an indirect lexicographic sort. For some reason it sorts the last row first, so in your case we have to take the transpose and reverse the order of x and y .

>>> A
array([[0.1, 0.2],
       [0.5, 0.1],
       [0.3, 0.9],
       [0.7, 1. ],
       [0.1, 0.3],
       [0.2, 0.3]])
>>> A[np.lexsort(A.T[::-1])]
array([[0.1, 0.2],
       [0.1, 0.3],
       [0.2, 0.3],
       [0.3, 0.9],
       [0.5, 0.1],
       [0.7, 1. ]])