Return an array of ones with the same shape and type as a given array.
With default parameters, is equivalent to a.copy().fill(1).
| Parameters : | a : array_like 
 dtype : data-type, optional 
 order : {‘C’, ‘F’, ‘A’, or ‘K’}, optional 
  | 
|---|---|
| Returns : | out : ndarray 
  | 
See also
Examples
>>> x = np.arange(6)
>>> x = x.reshape((2, 3))
>>> x
array([[0, 1, 2],
       [3, 4, 5]])
>>> np.ones_like(x)
array([[1, 1, 1],
       [1, 1, 1]])
>>> y = np.arange(3, dtype=np.float)
>>> y
array([ 0.,  1.,  2.])
>>> np.ones_like(y)
array([ 1.,  1.,  1.])