numpy.ma.where  
numpy.ma.where(condition, x=<no value>, y=<no value>) [source]
 
Return a masked array with elements from x or y, depending on condition. Returns a masked array, shaped like condition, where the elements are from x when condition is True, and from y otherwise. If neither x nor y are given, the function returns a tuple of indices where condition is True (the result of condition.nonzero()).    
Parameters:

 
condition : array_like, bool  
The condition to meet. For each True element, yield the corresponding element from x, otherwise from y.  
x, y : array_like, optional  
Values from which to choose. x, y and condition need to be broadcastable to some shape.     
Returns:

 
out : MaskedArray or tuple of ndarrays  
The resulting masked array if x and y were given, otherwise the result of condition.nonzero().       See also  
numpy.where
 Equivalent function in the top-level NumPy module.   Examples >>> x = np.ma.array(np.arange(9.).reshape(3, 3), mask=[[0, 1, 0],
...                                                    [1, 0, 1],
...                                                    [0, 1, 0]])
>>> print(x)
[[0.0 -- 2.0]
 [-- 4.0 --]
 [6.0 -- 8.0]]
>>> np.ma.where(x > 5)    # return the indices where x > 5
(array([2, 2]), array([0, 2]))
 >>> print(np.ma.where(x > 5, x, -3.1416))
[[-3.1416 -- -3.1416]
 [-- -3.1416 --]
 [6.0 -- 8.0]]
 


    
{'path': 'public/docs/numpy~1.15/generated/numpy.ma.where.html', 'source': 'DevDocs.IO'}