Python numpy.recarray() Examples

def test_recfromtxt(self):
        #
        data = TextIO('A,B\n0,1\n2,3')
        kwargs = dict(delimiter=",", missing_values="N/A", names=True)
        test = np.recfromtxt(data, **kwargs)
        control = np.array([(0, 1), (2, 3)],
                           dtype=[('A', np.int), ('B', np.int)])
        self.assertTrue(isinstance(test, np.recarray))
        assert_equal(test, control)
        #
        data = TextIO('A,B\n0,1\n2,N/A')
        test = np.recfromtxt(data, dtype=None, usemask=True, **kwargs)
        control = ma.array([(0, 1), (2, -1)],
                           mask=[(False, False), (False, True)],
                           dtype=[('A', np.int), ('B', np.int)])
        assert_equal(test, control)
        assert_equal(test.mask, control.mask)
        assert_equal(test.A, [0, 2]) 

def __init__(self,fileobj, hdr):
        """ gets list of frames and subheaders in pet file

        Parameters
        -----------
        fileobj : ECAT file <filename>.v  fileholder or file object
                  with read, seek methods

        Returns
        -------
        mlist : numpy recarray  nframes X 4 columns
        1 - Matrix identifier.
        2 - subheader record number
        3 - Last record number of matrix data block.
        4 - Matrix status:
            1 - exists - rw
            2 - exists - ro
            3 - matrix deleted
        """
        self.hdr = hdr
        self._mlist = self.get_mlist(fileobj) 

def _keep_fields(base, keep_names, usemask=True, asrecarray=False):
    """
    Return a new array keeping only the fields in `keep_names`,
    and preserving the order of those fields.

    Parameters
    ----------
    base : array
        Input array
    keep_names : string or sequence
        String or sequence of strings corresponding to the names of the
        fields to keep. Order of the names will be preserved.
    usemask : {False, True}, optional
        Whether to return a masked array or not.
    asrecarray : string or sequence, optional
        Whether to return a recarray or a mrecarray (`asrecarray=True`) or
        a plain ndarray or masked array with flexible dtype. The default
        is False.
    """
    newdtype = [(n, base.dtype[n]) for n in keep_names]
    output = np.empty(base.shape, dtype=newdtype)
    output = recursive_fill_fields(base, output)
    return _fix_output(output, usemask=usemask, asrecarray=asrecarray) 

def test_recarray_from_repr(self):
        a = np.array([(1,'ABC'), (2, "DEF")],
                     dtype=[('foo', int), ('bar', 'S4')])
        recordarr = np.rec.array(a)
        recarr = a.view(np.recarray)
        recordview = a.view(np.dtype((np.record, a.dtype)))

        recordarr_r = eval("numpy." + repr(recordarr), {'numpy': np})
        recarr_r = eval("numpy." + repr(recarr), {'numpy': np})
        recordview_r = eval("numpy." + repr(recordview), {'numpy': np})

        assert_equal(type(recordarr_r), np.recarray)
        assert_equal(recordarr_r.dtype.type, np.record)
        assert_equal(recordarr, recordarr_r)

        assert_equal(type(recarr_r), np.recarray)
        assert_equal(recarr_r.dtype.type, np.record)
        assert_equal(recarr, recarr_r)

        assert_equal(type(recordview_r), np.ndarray)
        assert_equal(recordview.dtype.type, np.record)
        assert_equal(recordview, recordview_r) 

def _keep_fields(base, keep_names, usemask=True, asrecarray=False):
    """
    Return a new array keeping only the fields in `keep_names`,
    and preserving the order of those fields.

    Parameters
    ----------
    base : array
        Input array
    keep_names : string or sequence
        String or sequence of strings corresponding to the names of the
        fields to keep. Order of the names will be preserved.
    usemask : {False, True}, optional
        Whether to return a masked array or not.
    asrecarray : string or sequence, optional
        Whether to return a recarray or a mrecarray (`asrecarray=True`) or
        a plain ndarray or masked array with flexible dtype. The default
        is False.
    """
    newdtype = [(n, base.dtype[n]) for n in keep_names]
    output = np.empty(base.shape, dtype=newdtype)
    output = recursive_fill_fields(base, output)
    return _fix_output(output, usemask=usemask, asrecarray=asrecarray) 

def _keep_fields(base, keep_names, usemask=True, asrecarray=False):
    """
    Return a new array keeping only the fields in `keep_names`,
    and preserving the order of those fields.

    Parameters
    ----------
    base : array
        Input array
    keep_names : string or sequence
        String or sequence of strings corresponding to the names of the
        fields to keep. Order of the names will be preserved.
    usemask : {False, True}, optional
        Whether to return a masked array or not.
    asrecarray : string or sequence, optional
        Whether to return a recarray or a mrecarray (`asrecarray=True`) or
        a plain ndarray or masked array with flexible dtype. The default
        is False.
    """
    newdtype = [(n, base.dtype[n]) for n in keep_names]
    output = np.empty(base.shape, dtype=newdtype)
    output = recursive_fill_fields(base, output)
    return _fix_output(output, usemask=usemask, asrecarray=asrecarray) 

def test_recfromtxt(self):
        #
        data = TextIO('A,B\n0,1\n2,3')
        kwargs = dict(delimiter=",", missing_values="N/A", names=True)
        test = np.recfromtxt(data, **kwargs)
        control = np.array([(0, 1), (2, 3)],
                           dtype=[('A', int), ('B', int)])
        assert_(isinstance(test, np.recarray))
        assert_equal(test, control)
        #
        data = TextIO('A,B\n0,1\n2,N/A')
        test = np.recfromtxt(data, dtype=None, usemask=True, **kwargs)
        control = ma.array([(0, 1), (2, -1)],
                           mask=[(False, False), (False, True)],
                           dtype=[('A', int), ('B', int)])
        assert_equal(test, control)
        assert_equal(test.mask, control.mask)
        assert_equal(test.A, [0, 2]) 

def test_recfromtxt(self):
        #
        data = TextIO('A,B\n0,1\n2,3')
        kwargs = dict(delimiter=",", missing_values="N/A", names=True)
        test = np.recfromtxt(data, **kwargs)
        control = np.array([(0, 1), (2, 3)],
                           dtype=[('A', int), ('B', int)])
        assert_(isinstance(test, np.recarray))
        assert_equal(test, control)
        #
        data = TextIO('A,B\n0,1\n2,N/A')
        test = np.recfromtxt(data, dtype=None, usemask=True, **kwargs)
        control = ma.array([(0, 1), (2, -1)],
                           mask=[(False, False), (False, True)],
                           dtype=[('A', int), ('B', int)])
        assert_equal(test, control)
        assert_equal(test.mask, control.mask)
        assert_equal(test.A, [0, 2]) 

def test_recarray_from_repr(self):
        a = np.array([(1,'ABC'), (2, "DEF")],
                     dtype=[('foo', int), ('bar', 'S4')])
        recordarr = np.rec.array(a)
        recarr = a.view(np.recarray)
        recordview = a.view(np.dtype((np.record, a.dtype)))

        recordarr_r = eval("numpy." + repr(recordarr), {'numpy': np})
        recarr_r = eval("numpy." + repr(recarr), {'numpy': np})
        recordview_r = eval("numpy." + repr(recordview), {'numpy': np})

        assert_equal(type(recordarr_r), np.recarray)
        assert_equal(recordarr_r.dtype.type, np.record)
        assert_equal(recordarr, recordarr_r)

        assert_equal(type(recarr_r), np.recarray)
        assert_equal(recarr_r.dtype.type, np.record)
        assert_equal(recarr, recarr_r)

        assert_equal(type(recordview_r), np.ndarray)
        assert_equal(recordview.dtype.type, np.record)
        assert_equal(recordview, recordview_r) 

def recfromtxt(fname, **kwargs):
    """
    Load ASCII data from a file and return it in a record array.

    If ``usemask=False`` a standard `recarray` is returned,
    if ``usemask=True`` a MaskedRecords array is returned.

    Parameters
    ----------
    fname, kwargs : For a description of input parameters, see `genfromtxt`.

    See Also
    --------
    numpy.genfromtxt : generic function

    Notes
    -----
    By default, `dtype` is None, which means that the data-type of the output
    array will be determined from the data.

    """
    kwargs.setdefault("dtype", None)
    usemask = kwargs.get('usemask', False)
    output = genfromtxt(fname, **kwargs)
    if usemask:
        from numpy.ma.mrecords import MaskedRecords
        output = output.view(MaskedRecords)
    else:
        output = output.view(np.recarray)
    return output 

def test_record_scalar_setitem(self):
        # https://github.com/numpy/numpy/issues/3561
        rec = np.recarray(1, dtype=[('x', float, 5)])
        rec[0].x = 1
        assert_equal(rec[0].x, np.ones(5)) 

def recfromcsv(fname, **kwargs):
    """
    Load ASCII data stored in a comma-separated file.

    The returned array is a record array (if ``usemask=False``, see
    `recarray`) or a masked record array (if ``usemask=True``,
    see `ma.mrecords.MaskedRecords`).

    Parameters
    ----------
    fname, kwargs : For a description of input parameters, see `genfromtxt`.

    See Also
    --------
    numpy.genfromtxt : generic function to load ASCII data.

    Notes
    -----
    By default, `dtype` is None, which means that the data-type of the output
    array will be determined from the data.

    """
    # Set default kwargs for genfromtxt as relevant to csv import.
    kwargs.setdefault("case_sensitive", "lower")
    kwargs.setdefault("names", True)
    kwargs.setdefault("delimiter", ",")
    kwargs.setdefault("dtype", None)
    output = genfromtxt(fname, **kwargs)

    usemask = kwargs.get("usemask", False)
    if usemask:
        from numpy.ma.mrecords import MaskedRecords
        output = output.view(MaskedRecords)
    else:
        output = output.view(np.recarray)
    return output 

def test_byview(self):
        # Test creation by view
        base = self.base
        mbase = base.view(mrecarray)
        assert_equal(mbase.recordmask, base.recordmask)
        assert_equal_records(mbase._mask, base._mask)
        assert_(isinstance(mbase._data, recarray))
        assert_equal_records(mbase._data, base._data.view(recarray))
        for field in ('a', 'b', 'c'):
            assert_equal(base[field], mbase[field])
        assert_equal_records(mbase.view(mrecarray), mbase) 

def test_recarray_stringtypes(self):
        # Issue #3993
        a = np.array([('abc ', 1), ('abc', 2)],
                     dtype=[('foo', 'S4'), ('bar', int)])
        a = a.view(np.recarray)
        assert_equal(a.foo[0] == a.foo[1], False) 

def test_recfromtxt(self):
        with temppath(suffix='.txt') as path:
            path = Path(path)
            with path.open('w') as f:
                f.write(u'A,B\n0,1\n2,3')

            kwargs = dict(delimiter=",", missing_values="N/A", names=True)
            test = np.recfromtxt(path, **kwargs)
            control = np.array([(0, 1), (2, 3)],
                               dtype=[('A', int), ('B', int)])
            assert_(isinstance(test, np.recarray))
            assert_equal(test, control) 

def test_recfromcsv(self):
        with temppath(suffix='.txt') as path:
            path = Path(path)
            with path.open('w') as f:
                f.write(u'A,B\n0,1\n2,3')

            kwargs = dict(missing_values="N/A", names=True, case_sensitive=True)
            test = np.recfromcsv(path, dtype=None, **kwargs)
            control = np.array([(0, 1), (2, 3)],
                               dtype=[('A', int), ('B', int)])
            assert_(isinstance(test, np.recarray))
            assert_equal(test, control) 

def recfromtxt(fname, **kwargs):
    """
    Load ASCII data from a file and return it in a record array.

    If ``usemask=False`` a standard `recarray` is returned,
    if ``usemask=True`` a MaskedRecords array is returned.

    Parameters
    ----------
    fname, kwargs : For a description of input parameters, see `genfromtxt`.

    See Also
    --------
    numpy.genfromtxt : generic function

    Notes
    -----
    By default, `dtype` is None, which means that the data-type of the output
    array will be determined from the data.

    """
    kwargs.setdefault("dtype", None)
    usemask = kwargs.get('usemask', False)
    output = genfromtxt(fname, **kwargs)
    if usemask:
        from numpy.ma.mrecords import MaskedRecords
        output = output.view(MaskedRecords)
    else:
        output = output.view(np.recarray)
    return output 

def test_byview(self):
        # Test creation by view
        base = self.base
        mbase = base.view(mrecarray)
        assert_equal(mbase.recordmask, base.recordmask)
        assert_equal_records(mbase._mask, base._mask)
        assert_(isinstance(mbase._data, recarray))
        assert_equal_records(mbase._data, base._data.view(recarray))
        for field in ('a', 'b', 'c'):
            assert_equal(base[field], mbase[field])
        assert_equal_records(mbase.view(mrecarray), mbase) 

def test_record_scalar_setitem(self):
        # https://github.com/numpy/numpy/issues/3561
        rec = np.recarray(1, dtype=[('x', float, 5)])
        rec[0].x = 1
        assert_equal(rec[0].x, np.ones(5)) 

def test_recfromcsv(self):
        #
        data = TextIO('A,B\n0,1\n2,3')
        kwargs = dict(missing_values="N/A", names=True, case_sensitive=True)
        test = np.recfromcsv(data, dtype=None, **kwargs)
        control = np.array([(0, 1), (2, 3)],
                           dtype=[('A', np.int), ('B', np.int)])
        self.assertTrue(isinstance(test, np.recarray))
        assert_equal(test, control)
        #
        data = TextIO('A,B\n0,1\n2,N/A')
        test = np.recfromcsv(data, dtype=None, usemask=True, **kwargs)
        control = ma.array([(0, 1), (2, -1)],
                           mask=[(False, False), (False, True)],
                           dtype=[('A', np.int), ('B', np.int)])
        assert_equal(test, control)
        assert_equal(test.mask, control.mask)
        assert_equal(test.A, [0, 2])
        #
        data = TextIO('A,B\n0,1\n2,3')
        test = np.recfromcsv(data, missing_values='N/A',)
        control = np.array([(0, 1), (2, 3)],
                           dtype=[('a', np.int), ('b', np.int)])
        self.assertTrue(isinstance(test, np.recarray))
        assert_equal(test, control)
        #
        data = TextIO('A,B\n0,1\n2,3')
        dtype = [('a', np.int), ('b', np.float)]
        test = np.recfromcsv(data, missing_values='N/A', dtype=dtype)
        control = np.array([(0, 1), (2, 3)],
                           dtype=dtype)
        self.assertTrue(isinstance(test, np.recarray))
        assert_equal(test, control) 

def rec_join(key, r1, r2, jointype='inner', r1postfix='1', r2postfix='2',
             defaults=None):
    """
    Join arrays `r1` and `r2` on keys.
    Alternative to join_by, that always returns a np.recarray.

    See Also
    --------
    join_by : equivalent function
    """
    kwargs = dict(jointype=jointype, r1postfix=r1postfix, r2postfix=r2postfix,
                  defaults=defaults, usemask=False, asrecarray=True)
    return join_by(key, r1, r2, **kwargs) 

def rec_append_fields(base, names, data, dtypes=None):
    """
    Add new fields to an existing array.

    The names of the fields are given with the `names` arguments,
    the corresponding values with the `data` arguments.
    If a single field is appended, `names`, `data` and `dtypes` do not have
    to be lists but just values.

    Parameters
    ----------
    base : array
        Input array to extend.
    names : string, sequence
        String or sequence of strings corresponding to the names
        of the new fields.
    data : array or sequence of arrays
        Array or sequence of arrays storing the fields to add to the base.
    dtypes : sequence of datatypes, optional
        Datatype or sequence of datatypes.
        If None, the datatypes are estimated from the `data`.

    See Also
    --------
    append_fields

    Returns
    -------
    appended_array : np.recarray
    """
    return append_fields(base, names, data=data, dtypes=dtypes,
                         asrecarray=True, usemask=False) 

def rename_fields(base, namemapper):
    """
    Rename the fields from a flexible-datatype ndarray or recarray.

    Nested fields are supported.

    Parameters
    ----------
    base : ndarray
        Input array whose fields must be modified.
    namemapper : dictionary
        Dictionary mapping old field names to their new version.

    Examples
    --------
    >>> from numpy.lib import recfunctions as rfn
    >>> a = np.array([(1, (2, [3.0, 30.])), (4, (5, [6.0, 60.]))],
    ...   dtype=[('a', int),('b', [('ba', float), ('bb', (float, 2))])])
    >>> rfn.rename_fields(a, {'a':'A', 'bb':'BB'})
    array([(1, (2.0, [3.0, 30.0])), (4, (5.0, [6.0, 60.0]))],
          dtype=[('A', '<i4'), ('b', [('ba', '<f8'), ('BB', '<f8', 2)])])

    """
    def _recursive_rename_fields(ndtype, namemapper):
        newdtype = []
        for name in ndtype.names:
            newname = namemapper.get(name, name)
            current = ndtype[name]
            if current.names:
                newdtype.append(
                    (newname, _recursive_rename_fields(current, namemapper))
                    )
            else:
                newdtype.append((newname, current))
        return newdtype
    newdtype = _recursive_rename_fields(base.dtype, namemapper)
    return base.view(newdtype) 

def rec_drop_fields(base, drop_names):
    """
    Returns a new numpy.recarray with fields in `drop_names` dropped.
    """
    return drop_fields(base, drop_names, usemask=False, asrecarray=True) 

def _fix_output(output, usemask=True, asrecarray=False):
    """
    Private function: return a recarray, a ndarray, a MaskedArray
    or a MaskedRecords depending on the input parameters
    """
    if not isinstance(output, MaskedArray):
        usemask = False
    if usemask:
        if asrecarray:
            output = output.view(MaskedRecords)
    else:
        output = ma.filled(output)
        if asrecarray:
            output = output.view(recarray)
    return output 

def test_byview(self):
        # Test creation by view
        base = self.base
        mbase = base.view(mrecarray)
        assert_equal(mbase.recordmask, base.recordmask)
        assert_equal_records(mbase._mask, base._mask)
        assert_(isinstance(mbase._data, recarray))
        assert_equal_records(mbase._data, base._data.view(recarray))
        for field in ('a', 'b', 'c'):
            assert_equal(base[field], mbase[field])
        assert_equal_records(mbase.view(mrecarray), mbase) 

def recfromcsv(fname, **kwargs):
    """
    Load ASCII data stored in a comma-separated file.

    The returned array is a record array (if ``usemask=False``, see
    `recarray`) or a masked record array (if ``usemask=True``,
    see `ma.mrecords.MaskedRecords`).

    Parameters
    ----------
    fname, kwargs : For a description of input parameters, see `genfromtxt`.

    See Also
    --------
    numpy.genfromtxt : generic function to load ASCII data.

    Notes
    -----
    By default, `dtype` is None, which means that the data-type of the output
    array will be determined from the data.

    """
    # Set default kwargs for genfromtxt as relevant to csv import.
    kwargs.setdefault("case_sensitive", "lower")
    kwargs.setdefault("names", True)
    kwargs.setdefault("delimiter", ",")
    kwargs.setdefault("dtype", None)
    output = genfromtxt(fname, **kwargs)

    usemask = kwargs.get("usemask", False)
    if usemask:
        from numpy.ma.mrecords import MaskedRecords
        output = output.view(MaskedRecords)
    else:
        output = output.view(np.recarray)
    return output 

def recfromtxt(fname, **kwargs):
    """
    Load ASCII data from a file and return it in a record array.

    If ``usemask=False`` a standard `recarray` is returned,
    if ``usemask=True`` a MaskedRecords array is returned.

    Parameters
    ----------
    fname, kwargs : For a description of input parameters, see `genfromtxt`.

    See Also
    --------
    numpy.genfromtxt : generic function

    Notes
    -----
    By default, `dtype` is None, which means that the data-type of the output
    array will be determined from the data.

    """
    kwargs.setdefault("dtype", None)
    usemask = kwargs.get('usemask', False)
    output = genfromtxt(fname, **kwargs)
    if usemask:
        from numpy.ma.mrecords import MaskedRecords
        output = output.view(MaskedRecords)
    else:
        output = output.view(np.recarray)
    return output 

def test_recfromcsv(self):
        with temppath(suffix='.txt') as path:
            path = Path(path)
            with path.open('w') as f:
                f.write(u'A,B\n0,1\n2,3')

            kwargs = dict(missing_values="N/A", names=True, case_sensitive=True)
            test = np.recfromcsv(path, dtype=None, **kwargs)
            control = np.array([(0, 1), (2, 3)],
                               dtype=[('A', np.int), ('B', np.int)])
            self.assertTrue(isinstance(test, np.recarray))
            assert_equal(test, control) 

def test_recfromcsv(self):
        #
        data = TextIO('A,B\n0,1\n2,3')
        kwargs = dict(missing_values="N/A", names=True, case_sensitive=True)
        test = np.recfromcsv(data, dtype=None, **kwargs)
        control = np.array([(0, 1), (2, 3)],
                           dtype=[('A', np.int), ('B', np.int)])
        self.assertTrue(isinstance(test, np.recarray))
        assert_equal(test, control)
        #
        data = TextIO('A,B\n0,1\n2,N/A')
        test = np.recfromcsv(data, dtype=None, usemask=True, **kwargs)
        control = ma.array([(0, 1), (2, -1)],
                           mask=[(False, False), (False, True)],
                           dtype=[('A', np.int), ('B', np.int)])
        assert_equal(test, control)
        assert_equal(test.mask, control.mask)
        assert_equal(test.A, [0, 2])
        #
        data = TextIO('A,B\n0,1\n2,3')
        test = np.recfromcsv(data, missing_values='N/A',)
        control = np.array([(0, 1), (2, 3)],
                           dtype=[('a', np.int), ('b', np.int)])
        self.assertTrue(isinstance(test, np.recarray))
        assert_equal(test, control)
        #
        data = TextIO('A,B\n0,1\n2,3')
        dtype = [('a', np.int), ('b', np.float)]
        test = np.recfromcsv(data, missing_values='N/A', dtype=dtype)
        control = np.array([(0, 1), (2, 3)],
                           dtype=dtype)
        self.assertTrue(isinstance(test, np.recarray))
        assert_equal(test, control)