def get_masked_subclass(*arrays):
"""
Return the youngest subclass of MaskedArray from a list of (masked) arrays.
In case of siblings, the first listed takes over.
"""
if len(arrays) == 1:
arr = arrays[0]
if isinstance(arr, MaskedArray):
rcls = type(arr)
else:
rcls = MaskedArray
else:
arrcls = [type(a) for a in arrays]
rcls = arrcls[0]
if not issubclass(rcls, MaskedArray):
rcls = MaskedArray
for cls in arrcls[1:]:
if issubclass(cls, rcls):
rcls = cls
# Don't return MaskedConstant as result: revert to MaskedArray
if rcls.__name__ == 'MaskedConstant':
return MaskedArray
return rcls
python类masked()的实例源码
def outer(self, a, b):
"""
Return the function applied to the outer product of a and b.
"""
(da, db) = (getdata(a), getdata(b))
d = self.f.outer(da, db)
ma = getmask(a)
mb = getmask(b)
if ma is nomask and mb is nomask:
m = nomask
else:
ma = getmaskarray(a)
mb = getmaskarray(b)
m = umath.logical_or.outer(ma, mb)
if (not m.ndim) and m:
return masked
if m is not nomask:
np.copyto(d, da, where=m)
if not d.shape:
return d
masked_d = d.view(get_masked_subclass(a, b))
masked_d._mask = m
return masked_d
def unshare_mask(self):
"""
Copy the mask and set the sharedmask flag to False.
Whether the mask is shared between masked arrays can be seen from
the `sharedmask` property. `unshare_mask` ensures the mask is not shared.
A copy of the mask is only made if it was shared.
See Also
--------
sharedmask
"""
if self._sharedmask:
self._mask = self._mask.copy()
self._sharedmask = False
return self
def resize(self, newshape, refcheck=True, order=False):
"""
.. warning::
This method does nothing, except raise a ValueError exception. A
masked array does not own its data and therefore cannot safely be
resized in place. Use the `numpy.ma.resize` function instead.
This method is difficult to implement safely and may be deprecated in
future releases of NumPy.
"""
# Note : the 'order' keyword looks broken, let's just drop it
errmsg = "A masked array does not own its data "\
"and therefore cannot be resized.\n" \
"Use the numpy.ma.resize function instead."
raise ValueError(errmsg)
def round(self, decimals=0, out=None):
"""
Return an array rounded a to the given number of decimals.
Refer to `numpy.around` for full documentation.
See Also
--------
numpy.around : equivalent function
"""
result = self._data.round(decimals=decimals, out=out).view(type(self))
if result.ndim > 0:
result._mask = self._mask
result._update_from(self)
elif self._mask:
# Return masked when the scalar is masked
result = masked
# No explicit output: we're done
if out is None:
return result
if isinstance(out, MaskedArray):
out.__setmask__(self._mask)
return out
def take(self, indices, axis=None, out=None, mode='raise'):
"""
"""
(_data, _mask) = (self._data, self._mask)
cls = type(self)
# Make sure the indices are not masked
maskindices = getattr(indices, '_mask', nomask)
if maskindices is not nomask:
indices = indices.filled(0)
# Get the data
if out is None:
out = _data.take(indices, axis=axis, mode=mode).view(cls)
else:
np.take(_data, indices, axis=axis, mode=mode, out=out)
# Get the mask
if isinstance(out, MaskedArray):
if _mask is nomask:
outmask = maskindices
else:
outmask = _mask.take(indices, axis=axis, mode=mode)
outmask |= maskindices
out.__setmask__(outmask)
return out
# Array methods
def __getstate__(self):
"""Return the internal state of the masked array, for pickling
purposes.
"""
cf = 'CF'[self.flags.fnc]
state = (1,
self.shape,
self.dtype,
self.flags.fnc,
self._data.tobytes(cf),
# self._data.tolist(),
getmaskarray(self).tobytes(cf),
# getmaskarray(self).tolist(),
self._fill_value,
)
return state
def __setstate__(self, state):
"""Restore the internal state of the masked array, for
pickling purposes. ``state`` is typically the output of the
``__getstate__`` output, and is a 5-tuple:
- class name
- a tuple giving the shape of the data
- a typecode for the data
- a binary string for the data
- a binary string for the mask.
"""
(_, shp, typ, isf, raw, msk, flv) = state
super(MaskedArray, self).__setstate__((shp, typ, isf, raw))
self._mask.__setstate__((shp, make_mask_descr(typ), isf, msk))
self.fill_value = flv
def __getitem__(self, indx):
"""
Get the index.
"""
m = self._mask
if isinstance(m[indx], ndarray):
# Can happen when indx is a multi-dimensional field:
# A = ma.masked_array(data=[([0,1],)], mask=[([True,
# False],)], dtype=[("A", ">i2", (2,))])
# x = A[0]; y = x["A"]; then y.mask["A"].size==2
# and we can not say masked/unmasked.
# The result is no longer mvoid!
# See also issue #6724.
return masked_array(
data=self._data[indx], mask=m[indx],
fill_value=self._fill_value[indx],
hard_mask=self._hardmask)
if m is not nomask and m[indx]:
return masked
return self._data[indx]
def filled(self, fill_value=None):
"""
Return a copy with masked fields filled with a given value.
Parameters
----------
fill_value : scalar, optional
The value to use for invalid entries (None by default).
If None, the `fill_value` attribute is used instead.
Returns
-------
filled_void
A `np.void` object
See Also
--------
MaskedArray.filled
"""
return asarray(self).filled(fill_value)[()]
def reduce(self, target, axis=None):
"Reduce target along the given axis."
target = narray(target, copy=False, subok=True)
m = getmask(target)
if axis is not None:
kargs = {'axis': axis}
else:
kargs = {}
target = target.ravel()
if not (m is nomask):
m = m.ravel()
if m is nomask:
t = self.ufunc.reduce(target, **kargs)
else:
target = target.filled(
self.fill_value_func(target)).view(type(target))
t = self.ufunc.reduce(target, **kargs)
m = umath.logical_and.reduce(m, **kargs)
if hasattr(t, '_mask'):
t._mask = m
elif m:
t = masked
return t
def compressed(x):
"""
Return all the non-masked data as a 1-D array.
This function is equivalent to calling the "compressed" method of a
`MaskedArray`, see `MaskedArray.compressed` for details.
See Also
--------
MaskedArray.compressed
Equivalent method.
"""
if not isinstance(x, MaskedArray):
x = asanyarray(x)
return x.compressed()
def left_shift(a, n):
"""
Shift the bits of an integer to the left.
This is the masked array version of `numpy.left_shift`, for details
see that function.
See Also
--------
numpy.left_shift
"""
m = getmask(a)
if m is nomask:
d = umath.left_shift(filled(a), n)
return masked_array(d)
else:
d = umath.left_shift(filled(a, 0), n)
return masked_array(d, mask=m)
def right_shift(a, n):
"""
Shift the bits of an integer to the right.
This is the masked array version of `numpy.right_shift`, for details
see that function.
See Also
--------
numpy.right_shift
"""
m = getmask(a)
if m is nomask:
d = umath.right_shift(filled(a), n)
return masked_array(d)
else:
d = umath.right_shift(filled(a, 0), n)
return masked_array(d, mask=m)
def dump(a, F):
"""
Pickle a masked array to a file.
This is a wrapper around ``cPickle.dump``.
Parameters
----------
a : MaskedArray
The array to be pickled.
F : str or file-like object
The file to pickle `a` to. If a string, the full path to the file.
"""
if not hasattr(F, 'readline'):
F = open(F, 'w')
return pickle.dump(a, F)
def loads(strg):
"""
Load a pickle from the current string.
The result of ``cPickle.loads(strg)`` is returned.
Parameters
----------
strg : str
The string to load.
See Also
--------
dumps : Return a string corresponding to the pickling of a masked array.
"""
return pickle.loads(strg)
def get_masked_subclass(*arrays):
"""
Return the youngest subclass of MaskedArray from a list of (masked) arrays.
In case of siblings, the first listed takes over.
"""
if len(arrays) == 1:
arr = arrays[0]
if isinstance(arr, MaskedArray):
rcls = type(arr)
else:
rcls = MaskedArray
else:
arrcls = [type(a) for a in arrays]
rcls = arrcls[0]
if not issubclass(rcls, MaskedArray):
rcls = MaskedArray
for cls in arrcls[1:]:
if issubclass(cls, rcls):
rcls = cls
# Don't return MaskedConstant as result: revert to MaskedArray
if rcls.__name__ == 'MaskedConstant':
return MaskedArray
return rcls
def outer(self, a, b):
"""
Return the function applied to the outer product of a and b.
"""
(da, db) = (getdata(a), getdata(b))
d = self.f.outer(da, db)
ma = getmask(a)
mb = getmask(b)
if ma is nomask and mb is nomask:
m = nomask
else:
ma = getmaskarray(a)
mb = getmaskarray(b)
m = umath.logical_or.outer(ma, mb)
if (not m.ndim) and m:
return masked
if m is not nomask:
np.copyto(d, da, where=m)
if not d.shape:
return d
masked_d = d.view(get_masked_subclass(a, b))
masked_d._mask = m
return masked_d
def unshare_mask(self):
"""
Copy the mask and set the sharedmask flag to False.
Whether the mask is shared between masked arrays can be seen from
the `sharedmask` property. `unshare_mask` ensures the mask is not shared.
A copy of the mask is only made if it was shared.
See Also
--------
sharedmask
"""
if self._sharedmask:
self._mask = self._mask.copy()
self._sharedmask = False
return self
def resize(self, newshape, refcheck=True, order=False):
"""
.. warning::
This method does nothing, except raise a ValueError exception. A
masked array does not own its data and therefore cannot safely be
resized in place. Use the `numpy.ma.resize` function instead.
This method is difficult to implement safely and may be deprecated in
future releases of NumPy.
"""
# Note : the 'order' keyword looks broken, let's just drop it
errmsg = "A masked array does not own its data "\
"and therefore cannot be resized.\n" \
"Use the numpy.ma.resize function instead."
raise ValueError(errmsg)
def round(self, decimals=0, out=None):
"""
Return an array rounded a to the given number of decimals.
Refer to `numpy.around` for full documentation.
See Also
--------
numpy.around : equivalent function
"""
result = self._data.round(decimals=decimals, out=out).view(type(self))
if result.ndim > 0:
result._mask = self._mask
result._update_from(self)
elif self._mask:
# Return masked when the scalar is masked
result = masked
# No explicit output: we're done
if out is None:
return result
if isinstance(out, MaskedArray):
out.__setmask__(self._mask)
return out
def take(self, indices, axis=None, out=None, mode='raise'):
"""
"""
(_data, _mask) = (self._data, self._mask)
cls = type(self)
# Make sure the indices are not masked
maskindices = getattr(indices, '_mask', nomask)
if maskindices is not nomask:
indices = indices.filled(0)
# Get the data
if out is None:
out = _data.take(indices, axis=axis, mode=mode).view(cls)
else:
np.take(_data, indices, axis=axis, mode=mode, out=out)
# Get the mask
if isinstance(out, MaskedArray):
if _mask is nomask:
outmask = maskindices
else:
outmask = _mask.take(indices, axis=axis, mode=mode)
outmask |= maskindices
out.__setmask__(outmask)
return out
# Array methods
def __getstate__(self):
"""Return the internal state of the masked array, for pickling
purposes.
"""
cf = 'CF'[self.flags.fnc]
state = (1,
self.shape,
self.dtype,
self.flags.fnc,
self._data.tobytes(cf),
# self._data.tolist(),
getmaskarray(self).tobytes(cf),
# getmaskarray(self).tolist(),
self._fill_value,
)
return state
def __setstate__(self, state):
"""Restore the internal state of the masked array, for
pickling purposes. ``state`` is typically the output of the
``__getstate__`` output, and is a 5-tuple:
- class name
- a tuple giving the shape of the data
- a typecode for the data
- a binary string for the data
- a binary string for the mask.
"""
(_, shp, typ, isf, raw, msk, flv) = state
super(MaskedArray, self).__setstate__((shp, typ, isf, raw))
self._mask.__setstate__((shp, make_mask_descr(typ), isf, msk))
self.fill_value = flv
def __getitem__(self, indx):
"""
Get the index.
"""
m = self._mask
if isinstance(m[indx], ndarray):
# Can happen when indx is a multi-dimensional field:
# A = ma.masked_array(data=[([0,1],)], mask=[([True,
# False],)], dtype=[("A", ">i2", (2,))])
# x = A[0]; y = x["A"]; then y.mask["A"].size==2
# and we can not say masked/unmasked.
# The result is no longer mvoid!
# See also issue #6724.
return masked_array(
data=self._data[indx], mask=m[indx],
fill_value=self._fill_value[indx],
hard_mask=self._hardmask)
if m is not nomask and m[indx]:
return masked
return self._data[indx]
def filled(self, fill_value=None):
"""
Return a copy with masked fields filled with a given value.
Parameters
----------
fill_value : scalar, optional
The value to use for invalid entries (None by default).
If None, the `fill_value` attribute is used instead.
Returns
-------
filled_void
A `np.void` object
See Also
--------
MaskedArray.filled
"""
return asarray(self).filled(fill_value)[()]
def reduce(self, target, axis=None):
"Reduce target along the given axis."
target = narray(target, copy=False, subok=True)
m = getmask(target)
if axis is not None:
kargs = {'axis': axis}
else:
kargs = {}
target = target.ravel()
if not (m is nomask):
m = m.ravel()
if m is nomask:
t = self.ufunc.reduce(target, **kargs)
else:
target = target.filled(
self.fill_value_func(target)).view(type(target))
t = self.ufunc.reduce(target, **kargs)
m = umath.logical_and.reduce(m, **kargs)
if hasattr(t, '_mask'):
t._mask = m
elif m:
t = masked
return t
def compressed(x):
"""
Return all the non-masked data as a 1-D array.
This function is equivalent to calling the "compressed" method of a
`MaskedArray`, see `MaskedArray.compressed` for details.
See Also
--------
MaskedArray.compressed
Equivalent method.
"""
if not isinstance(x, MaskedArray):
x = asanyarray(x)
return x.compressed()
def left_shift(a, n):
"""
Shift the bits of an integer to the left.
This is the masked array version of `numpy.left_shift`, for details
see that function.
See Also
--------
numpy.left_shift
"""
m = getmask(a)
if m is nomask:
d = umath.left_shift(filled(a), n)
return masked_array(d)
else:
d = umath.left_shift(filled(a, 0), n)
return masked_array(d, mask=m)
def right_shift(a, n):
"""
Shift the bits of an integer to the right.
This is the masked array version of `numpy.right_shift`, for details
see that function.
See Also
--------
numpy.right_shift
"""
m = getmask(a)
if m is nomask:
d = umath.right_shift(filled(a), n)
return masked_array(d)
else:
d = umath.right_shift(filled(a, 0), n)
return masked_array(d, mask=m)
