def concatenate(self, others : List[Categorical], ordered : bool=True) -> Categorical:
"""
Merge this Categorical with other Categorical objects in the array,
concatenating the arrays and synchronizing the categories.
Parameters
----------
others : List[Categorical]
The Categorical arrays to concatenate and merge with this one
ordered : bool
If True (default), the arrays will be appended in the
order given. If False, array data may be interleaved
in blocks, which can greatly improve performance but
results in non-deterministic ordering of elements.
Returns
-------
Categorical
The merged Categorical object
Raises
------
TypeError
Raised if any others array objects are not Categorical objects
Notes
-----
This operation can be expensive -- slower than concatenating Strings.
"""
if isinstance(others, Categorical):
others = [others]
elif len(others) < 1:
return self
samecategories = True
for c in others:
if not isinstance(c, Categorical):
raise TypeError(("Categorical: can only merge/concatenate " +
"with other Categoricals"))
if (self.categories.size != c.categories.size) or not \
(self.categories == c.categories).all():
samecategories = False
if samecategories:
newvals = cast(pdarray, concatenate([self.codes] + [o.codes for o in others], ordered=ordered))
return Categorical.from_codes(newvals, self.categories)
else:
g = GroupBy(concatenate([self.categories] + \
[o.categories for o in others],
ordered=False))
newidx = g.unique_keys
wherediditgo = zeros(newidx.size, dtype=akint64)
wherediditgo[g.permutation] = arange(newidx.size)
idxsizes = np.array([self.categories.size] + \
[o.categories.size for o in others])
idxoffsets = np.cumsum(idxsizes) - idxsizes
oldvals = concatenate([c + off for c, off in \
zip([self.codes] + [o.codes for o in others], idxoffsets)],
ordered=ordered)
newvals = wherediditgo[oldvals]
return Categorical.from_codes(newvals, newidx)
def merge(self, others : List[Categorical]) -> Categorical:
"""
Merge this Categorical with other Categorical objects in the array,
concatenating the arrays and synchronizing the categories.
Parameters
----------
others : List[Categorical]
The Categorical arrays to concatenate and merge with this one
Returns
-------
Categorical
The merged Categorical object
Raises
------
TypeError
Raised if any others array objects are not Categorical objects
Notes
-----
This operation can be expensive -- slower than concatenating Strings.
"""
if isinstance(others, Categorical):
others = [others]
elif len(others) < 1:
return self
samecategories = True
for c in others:
if not isinstance(c, Categorical):
raise TypeError(("Categorical: can only merge/concatenate " +
"with other Categoricals"))
if (self.categories.size != c.categories.size) or not \
(self.categories == c.categories).all():
samecategories = False
if samecategories:
newvals = cast(pdarray, concatenate([self.codes] + [o.codes for o in others]))
return Categorical.from_codes(newvals, self.categories)
else:
g = GroupBy(concatenate([self.categories] + \
[o.categories for o in others]))
newidx = g.unique_keys
wherediditgo = zeros(newidx.size, dtype=akint64)
wherediditgo[g.permutation] = arange(newidx.size)
idxsizes = np.array([self.categories.size] + \
[o.categories.size for o in others])
idxoffsets = np.cumsum(idxsizes) - idxsizes
oldvals = concatenate([c.codes + off for c, off in zip([self.codes] \
+ [o.codes for o in others], idxoffsets)])
newvals = wherediditgo[oldvals]
return Categorical.from_codes(newvals, newidx)
def broadcast(self, values : pdarray) -> pdarray:
"""
Fill each group's segment with a constant value.
Parameters
----------
values : pdarray
The values to put in each group's segment
Returns
-------
pdarray
The broadcast values
Raises
------
TypeError
Raised if value is not a pdarray object
ValueError
Raised if the values array does not have one
value per segment
Notes
-----
This function is a sparse analog of ``np.broadcast``. If a
GroupBy object represents a sparse matrix (tensor), then
this function takes a (dense) column vector and replicates
each value to the non-zero elements in the corresponding row.
The returned array is in permuted (grouped) order. To get
back to the order of the array on which GroupBy was called,
the user must invert the permutation (see below).
Examples
--------
>>> a = ak.array([0, 1, 0, 1, 0])
>>> values = ak.array([3, 5])
>>> g = ak.GroupBy(a)
# Result is in grouped order
>>> g.broadcast(values)
array([3, 3, 3, 5, 5]
>>> b = ak.zeros_like(a)
# Result is in original order
>>> b[g.permutation] = g.broadcast(values)
>>> b
array([3, 5, 3, 5, 3])
"""
if not isinstance(values, pdarray):
raise TypeError("Vals must be pdarray")
if values.size != self.segments.size:
raise ValueError("Must have one value per segment")
temp = zeros(self.size, values.dtype)
if values.size == 0:
return temp
diffs = concatenate((array([values[0]]), values[1:] - values[:-1]))
temp[self.segments] = diffs
return cumsum(temp)
def broadcast(self, values : pdarray) -> pdarray:
"""
Fill each group's segment with a constant value.
Parameters
----------
values : pdarray
The values to put in each group's segment
Returns
-------
pdarray
The broadcast values
Raises
------
TypeError
Raised if value is not a pdarray object
ValueError
Raised if the values array does not have one
value per segment
Notes
-----
This function is a sparse analog of ``np.broadcast``. If a
GroupBy object represents a sparse matrix (tensor), then
this function takes a (dense) column vector and replicates
each value to the non-zero elements in the corresponding row.
The returned array is in permuted (grouped) order. To get
back to the order of the array on which GroupBy was called,
the user must invert the permutation (see below).
Examples
--------
>>> a = ak.array([0, 1, 0, 1, 0])
>>> values = ak.array([3, 5])
>>> g = ak.GroupBy(a)
# Result is in grouped order
>>> g.broadcast(values)
array([3, 3, 3, 5, 5]
>>> b = ak.zeros_like(a)
# Result is in original order
>>> b[g.permutation] = g.broadcast(values)
>>> b
array([3, 5, 3, 5, 3])
>>> a = ak.randint(1,5,10)
>>> a
array([3, 1, 4, 4, 4, 1, 3, 3, 2, 2])
>>> g = ak.GroupBy(a)
>>> keys,counts = g.count()
>>> g.broadcast(counts > 2)
array([0, 0, 0, 0, 1, 1, 1, 1, 1, 1])
>>> g.broadcast(counts == 3)
array([0, 0, 0, 0, 1, 1, 1, 1, 1, 1])
>>> g.broadcast(counts < 4)
array([1, 1, 1, 1, 1, 1, 1, 1, 1, 1])
"""
'''if values a boolean array, convert to an int64 array, which
is needed for now because Arkouda does not support broadcasting
of boolean arrays'''
if values.dtype == np.bool:
values = 1*values
if values.size != self.segments.size:
raise ValueError("Must have one value per segment")
temp = zeros(self.size, values.dtype)
if values.size == 0:
return temp
diffs = concatenate((array([values[0]]), values[1:] - values[:-1]))
temp[self.segments] = diffs
return cumsum(temp)
def _binop(self, other: Union[Categorical, str_scalars],
op: str_scalars) -> pdarray:
"""
Executes the requested binop on this Categorical instance and returns
the results within a pdarray object.
Parameters
----------
other : Union[Categorical,str_scalars]
the other object is a Categorical object or string scalar
op : str_scalars
name of the binary operation to be performed
Returns
-------
pdarray
encapsulating the results of the requested binop
Raises
- -----
ValueError
Raised if (1) the op is not in the self.BinOps set, or (2) if the
sizes of this and the other instance don't match
RuntimeError
Raised if a server-side error is thrown while executing the
binary operation
"""
if op not in self.BinOps:
raise NotImplementedError("Categorical: unsupported operator: {}".\
format(op))
if np.isscalar(other) and resolve_scalar_dtype(other) == "str":
idxresult = self.categories._binop(other, op)
return idxresult[self.codes]
if self.size != cast(Categorical, other).size:
raise ValueError("Categorical {}: size mismatch {} {}".\
format(op, self.size, cast(Categorical,other).size))
if isinstance(other, Categorical):
if (self.categories.size
== other.categories.size) and (self.categories
== other.categories).all():
# Because categories are identical, codes can be compared directly
return self.codes._binop(other.codes, op)
else:
# Remap both codes to the union of categories
union = unique(
concatenate((self.categories, other.categories),
ordered=False))
newinds = arange(union.size)
# Inds of self.categories in unioned categories
selfnewinds = newinds[in1d(union, self.categories)]
# Need a permutation and segments to broadcast new codes
if self.permutation is None or self.segments is None:
g = GroupBy(self.codes)
self.permutation = g.permutation
self.segments = g.segments
# Form new codes by broadcasting new indices for unioned categories
selfnewcodes = broadcast(self.segments, selfnewinds, self.size,
self.permutation)
# Repeat for other
othernewinds = newinds[in1d(union, other.categories)]
if other.permutation is None or other.segments is None:
g = GroupBy(other.codes)
other.permutation = g.permutation
other.segments = g.segments
othernewcodes = broadcast(other.segments, othernewinds,
other.size, other.permutation)
# selfnewcodes and othernewcodes now refer to same unioned categories
# and can be compared directly
return selfnewcodes._binop(othernewcodes, op)
else:
raise NotImplementedError(
("Operations between Categorical and " +
"non-Categorical not yet implemented. " +
"Consider converting operands to Categorical."))
