numpy.ma.indices

#### Next topic

The Array Interface

# 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. out : MaskedArray or tuple of ndarrays The resulting masked array if x and y were given, otherwise the result of `condition.nonzero()`.

`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]]
```