reference:maskedarray.baseclass

Constants of the numpy.ma module

In addition to the MaskedArray class, the numpy.ma module defines several constants.

The MaskedArray class

A subclass of ndarray designed to manipulate numerical arrays with missing data.

An instance of MaskedArray can be thought as the combination of several elements:

• The ~MaskedArray.data, as a regular numpy.ndarray of any shape or datatype (the data).

• A boolean ~numpy.ma.MaskedArray.mask with the same shape as the data, where a True value indicates that the corresponding element of the data is invalid. The special value nomask is also acceptable for arrays without named fields, and indicates that no data is invalid.

• A ~numpy.ma.MaskedArray.fill_value, a value that may be used to replace the invalid entries in order to return a standard numpy.ndarray.

Attributes and properties of masked arrays

As MaskedArray is a subclass of ndarray, a masked array also inherits all the attributes and properties of a ndarray instance.

.. autosummary:: 
    :toctree:generated/
    MaskedArray.base
    MaskedArray.ctypes
    MaskedArray.dtype
    MaskedArray.flags

    MaskedArray.itemsize
    MaskedArray.nbytes
    MaskedArray.ndim
    MaskedArray.shape
    MaskedArray.size
    MaskedArray.strides

    MaskedArray.imag
    MaskedArray.real

    MaskedArray.flat
    MaskedArray.__array_priority__

MaskedArray methods

Conversion

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__float__
    MaskedArray.__int__

    MaskedArray.view
    MaskedArray.astype
    MaskedArray.byteswap

    MaskedArray.compressed
    MaskedArray.filled
    MaskedArray.tofile
    MaskedArray.toflex
    MaskedArray.tolist
    MaskedArray.torecords
    MaskedArray.tobytes

Shape manipulation

For reshape, resize, and transpose, the single tuple argument may be replaced with n integers which will be interpreted as an n-tuple.

.. autosummary:: 
    :toctree:generated/
    MaskedArray.flatten
    MaskedArray.ravel
    MaskedArray.reshape
    MaskedArray.resize
    MaskedArray.squeeze
    MaskedArray.swapaxes
    MaskedArray.transpose
    MaskedArray.T

Item selection and manipulation

For array methods that take an axis keyword, it defaults to None. If axis is None, then the array is treated as a 1-D array. Any other value for axis represents the dimension along which the operation should proceed.

.. autosummary:: 
    :toctree:generated/
    MaskedArray.argmax
    MaskedArray.argmin
    MaskedArray.argsort
    MaskedArray.choose
    MaskedArray.compress
    MaskedArray.diagonal
    MaskedArray.fill
    MaskedArray.item
    MaskedArray.nonzero
    MaskedArray.put
    MaskedArray.repeat
    MaskedArray.searchsorted
    MaskedArray.sort
    MaskedArray.take

Pickling and copy

.. autosummary:: 
    :toctree:generated/
    MaskedArray.copy
    MaskedArray.dump
    MaskedArray.dumps

Calculations

.. autosummary:: 
    :toctree:generated/
    MaskedArray.all
    MaskedArray.anom
    MaskedArray.any
    MaskedArray.clip
    MaskedArray.conj
    MaskedArray.conjugate
    MaskedArray.cumprod
    MaskedArray.cumsum
    MaskedArray.max
    MaskedArray.mean
    MaskedArray.min
    MaskedArray.prod
    MaskedArray.product
    MaskedArray.ptp
    MaskedArray.round
    MaskedArray.std
    MaskedArray.sum
    MaskedArray.trace
    MaskedArray.var

Arithmetic and comparison operations

Comparison operators:

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__lt__
    MaskedArray.__le__
    MaskedArray.__gt__
    MaskedArray.__ge__
    MaskedArray.__eq__
    MaskedArray.__ne__

Truth value of an array (bool() <bool>):

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__bool__

Arithmetic:

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__abs__
    MaskedArray.__add__
    MaskedArray.__radd__
    MaskedArray.__sub__
    MaskedArray.__rsub__
    MaskedArray.__mul__
    MaskedArray.__rmul__
    MaskedArray.__truediv__
    MaskedArray.__rtruediv__
    MaskedArray.__floordiv__
    MaskedArray.__rfloordiv__
    MaskedArray.__mod__
    MaskedArray.__rmod__
    MaskedArray.__divmod__
    MaskedArray.__rdivmod__
    MaskedArray.__pow__
    MaskedArray.__rpow__
    MaskedArray.__lshift__
    MaskedArray.__rlshift__
    MaskedArray.__rshift__
    MaskedArray.__rrshift__
    MaskedArray.__and__
    MaskedArray.__rand__
    MaskedArray.__or__
    MaskedArray.__ror__
    MaskedArray.__xor__
    MaskedArray.__rxor__

Arithmetic, in-place:

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__iadd__
    MaskedArray.__isub__
    MaskedArray.__imul__
    MaskedArray.__itruediv__
    MaskedArray.__ifloordiv__
    MaskedArray.__imod__
    MaskedArray.__ipow__
    MaskedArray.__ilshift__
    MaskedArray.__irshift__
    MaskedArray.__iand__
    MaskedArray.__ior__
    MaskedArray.__ixor__

Representation

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__repr__
    MaskedArray.__str__

    MaskedArray.ids
    MaskedArray.iscontiguous

Special methods

For standard library functions:

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__copy__
    MaskedArray.__deepcopy__
    MaskedArray.__getstate__
    MaskedArray.__reduce__
    MaskedArray.__setstate__

Basic customization:

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__new__
    MaskedArray.__array__
    MaskedArray.__array_wrap__

Container customization: (see Indexing)

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__len__
    MaskedArray.__getitem__
    MaskedArray.__setitem__
    MaskedArray.__delitem__
    MaskedArray.__contains__

Specific methods

Handling the mask

The following methods can be used to access information about the mask or to manipulate the mask.

.. autosummary:: 
    :toctree:generated/
    MaskedArray.__setmask__

    MaskedArray.harden_mask
    MaskedArray.soften_mask
    MaskedArray.unshare_mask
    MaskedArray.shrink_mask

Handling the fill_value

.. autosummary:: 
    :toctree:generated/
    MaskedArray.get_fill_value
    MaskedArray.set_fill_value

Counting the missing elements

.. autosummary:: 
    :toctree:generated/
    MaskedArray.count