Searching

NumPy has several functions that can search through arrays:

• The argmax() function gives the indices of the maximum values of an array:

  >>> a = np.array([2, 4, 8])
  >>> np.argmax(a)
  2
  

• The nanargmax() function does the same, but ignores NaN values:

  >>> b = np.array([np.nan, 2, 4])
  >>> np.nanargmax(b)
  2
  

• The argmin() and nanargmin() functions provide similar functionality but pertaining to minimum values. The argmax() and nanargmax() functions are also available as methods of the ndarray class.
• The argwhere() function searches for non-zero values and returns the corresponding indices grouped by element:

  >>> a = np.array([2, 4, 8])
  >>> np.argwhere(a <= 4)
  array([[0],
         [1]])
  

• The searchsorted() function tells you the index in an array where a specified value belongs to maintain the sort order. It uses binary search (see https://www.khanacademy.org/computing/computer-science/algorithms/binary-search/a/binary-search), which is a...