# 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.

Note

When only condition is provided, this function is identical to `nonzero`. The rest of this documentation covers only the case where all three arguments are provided.

Parameters: condition : array_like, bool Where True, yield x, otherwise yield y. x, y : array_like, optional Values from which to choose. x, y and condition need to be broadcastable to some shape. out : MaskedArray An masked array with `masked` elements where the condition is masked, elements from x where condition is True, and elements from y elsewhere.

`numpy.where`
Equivalent function in the top-level NumPy module.
`nonzero`
The function that is called when x and y are omitted

Examples

```>>> x = np.ma.array(np.arange(9.).reshape(3, 3), mask=[[0, 1, 0],
...                                                    [1, 0, 1],
...                                                    [0, 1, 0]])
>>> x
data=[[0.0, --, 2.0],
[--, 4.0, --],
[6.0, --, 8.0]],
[ True, False,  True],
[False,  True, False]],
fill_value=1e+20)
>>> np.ma.where(x > 5, x, -3.1416)
data=[[-3.1416, --, -3.1416],
[--, -3.1416, --],
[6.0, --, 8.0]],