Sorting arrays by column
With argsort, you get the index of the sorted array, which you can use to access the original array in sorted order. By selecting a single column for the sort algorithmn you can sort the array by the different columns
Assume an array with 3 columns and N rows
arr_org = np.random.rand((20,3))
idx=arr_org[:,3].argsort()
arr_sort =arr_org[idx]