numpy.ma.append

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`numpy.ma.``make_mask`(m, copy=False, shrink=True, dtype=<class 'numpy.bool_'>)[source]

Create a boolean mask from an array.

Return m as a boolean mask, creating a copy if necessary or requested. The function can accept any sequence that is convertible to integers, or `nomask`. Does not require that contents must be 0s and 1s, values of 0 are interpreted as False, everything else as True.

Parameters
marray_like

copybool, optional

Whether to return a copy of m (True) or m itself (False).

shrinkbool, optional

Whether to shrink m to `nomask` if all its values are False.

dtypedtype, optional

Data-type of the output mask. By default, the output mask has a dtype of MaskType (bool). If the dtype is flexible, each field has a boolean dtype. This is ignored when m is `nomask`, in which case `nomask` is always returned.

Returns
resultndarray

A boolean mask derived from m.

Examples

```>>> import numpy.ma as ma
>>> m = [True, False, True, True]
array([ True, False,  True,  True])
>>> m = [1, 0, 1, 1]
array([ True, False,  True,  True])
>>> m = [1, 0, 2, -3]
array([ True, False,  True,  True])
```

Effect of the shrink parameter.

```>>> m = np.zeros(4)
>>> m
array([0., 0., 0., 0.])
False
array([False, False, False, False])
```

Using a flexible dtype.

```>>> m = [1, 0, 1, 1]
>>> n = [0, 1, 0, 0]
>>> arr = []
>>> for man, mouse in zip(m, n):
...     arr.append((man, mouse))
>>> arr
[(1, 0), (0, 1), (1, 0), (1, 0)]
>>> dtype = np.dtype({'names':['man', 'mouse'],
...                   'formats':[np.int64, np.int64]})
>>> arr = np.array(arr, dtype=dtype)
>>> arr
array([(1, 0), (0, 1), (1, 0), (1, 0)],
dtype=[('man', '<i8'), ('mouse', '<i8')])