def compute_up(expr, data, **kwargs):
names = data.c.keys()
assert names == expr._child.fields
d = dict(zip(names, getattr(data, "inner_columns", data.c)))
return sa.select(
d[col].label(new_col) if col != new_col else d[col] for col, new_col in zip(expr._child.fields, expr.fields)
)
def test_unzip():
def _to_lists(seq, n=10):
"""iter of iters -> finite list of finite lists
"""
def initial(s):
return list(take(n, s))
return initial(map(initial, seq))
def _assert_initial_matches(a, b, n=10):
assert list(take(n, a)) == list(take(n, b))
# Unzips a simple list correctly
assert _to_lists(unzip([('a', 1), ('b', 2), ('c', 3)])) \
== [['a', 'b', 'c'], [1, 2, 3]]
# Can handle a finite number of infinite iterators (the naive unzip
# implementation `zip(*args)` impelementation fails on this example).
a, b, c = unzip(zip(count(1), repeat(0), repeat(1)))
_assert_initial_matches(a, count(1))
_assert_initial_matches(b, repeat(0))
_assert_initial_matches(c, repeat(1))
# Sensibly handles empty input
assert list(unzip(zip([]))) == []
def test_unzip():
def _to_lists(seq, n=10):
"""iter of iters -> finite list of finite lists
"""
def initial(s):
return list(take(n, s))
return initial(map(initial, seq))
def _assert_initial_matches(a, b, n=10):
assert list(take(n, a)) == list(take(n, b))
# Unzips a simple list correctly
assert _to_lists(unzip([('a', 1), ('b', 2), ('c', 3)])) \
== [['a', 'b', 'c'], [1, 2, 3]]
# Can handle a finite number of infinite iterators (the naive unzip
# implementation `zip(*args)` impelementation fails on this example).
a, b, c = unzip(zip(count(1), repeat(0), repeat(1)))
_assert_initial_matches(a, count(1))
_assert_initial_matches(b, repeat(0))
_assert_initial_matches(c, repeat(1))
# Sensibly handles empty input
assert list(unzip(zip([]))) == []
def compute_up(expr, data, **kwargs):
names = data.c.keys()
assert names == expr._child.fields
d = dict(zip(names, getattr(data, 'inner_columns', data.c)))
return sa.select(
d[col].label(new_col) if col != new_col else d[col]
for col, new_col in zip(expr._child.fields, expr.fields)
)
def compute_up(expr, data, **kwargs):
names = data.c.keys()
assert names == expr._child.fields, (
'names = %r\nexpr._child.fields = %r' % (names, expr._child.fields))
d = dict(zip(names, getattr(data, 'inner_columns', data.c)))
return reconstruct_select(
(d[col].label(new_col) if col != new_col else d[col]
for col, new_col in zip(expr._child.fields, expr.fields)),
data,
)
def compute_up(expr, data, **kwargs):
names = data.c.keys()
assert names == expr._child.fields, (
'names = %r\nexpr._child.fields = %r' % (names, expr._child.fields)
)
d = dict(zip(names, getattr(data, 'inner_columns', data.c)))
return reconstruct_select(
(d[col].label(new_col) if col != new_col else d[col]
for col, new_col in zip(expr._child.fields, expr.fields)),
data,
)
def from_delayed(values):
""" Create bag from many dask.delayed objects
Parameters
----------
values: list of Values
An iterable of dask.delayed.Value objects, such as come from dask.do
These comprise the individual partitions of the resulting bag
Returns
-------
Bag
Examples
--------
>>> b = from_delayed([x, y, z]) # doctest: +SKIP
"""
from dask.delayed import Value
if isinstance(values, Value):
values = [values]
dsk = merge(v.dask for v in values)
name = 'bag-from-delayed-' + tokenize(*values)
names = [(name, i) for i in range(len(values))]
values = [v.key for v in values]
dsk2 = dict(zip(names, values))
return Bag(merge(dsk, dsk2), name, len(values))
def compute_up(expr, data, **kwargs):
if not valid_grouper(expr.grouper):
raise TypeError("Grouper must have a non-nested record or one "
"dimensional collection datashape, "
"got %s of type %r with dshape %s" %
(expr.grouper, type(expr.grouper).__name__,
expr.grouper.dshape))
grouper = get_inner_columns(
compute(
expr.grouper,
data,
post_compute=False,
return_type='native',
),
)
app = expr.apply
reductions = [
compute(
val,
data,
post_compute=False,
return_type='native',
).label(name)
for val, name in zip(app.values, app.fields)
]
return sa.select(grouper + reductions).group_by(*grouper)
def compute_up(t, s, **kwargs):
columns = [
getattr(s.c, col).label(new_col) if col != new_col else getattr(
s.c, col) for col, new_col in zip(t._child.fields, t.fields)
]
return select(columns)
def compute_up(t, s, **kwargs):
columns = [getattr(s.c, col).label(new_col)
if col != new_col else
getattr(s.c, col)
for col, new_col in zip(t._child.fields, t.fields)]
return select(columns)
def from_delayed(values):
""" Create bag from many dask.delayed objects
Parameters
----------
values: list of Values
An iterable of dask.delayed.Value objects, such as come from dask.do
These comprise the individual partitions of the resulting bag
Returns
-------
Bag
Examples
--------
>>> b = from_delayed([x, y, z]) # doctest: +SKIP
"""
from dask.delayed import Value
if isinstance(values, Value):
values = [values]
dsk = merge(v.dask for v in values)
name = 'bag-from-delayed-' + tokenize(*values)
names = [(name, i) for i in range(len(values))]
values = [v.key for v in values]
dsk2 = dict(zip(names, values))
return Bag(merge(dsk, dsk2), name, len(values))
def compute_up(expr, data, scope=None, **kwargs):
data = lower_column(data)
grouper = compute(
expr.grouper,
scope,
post_compute=False,
return_type='native',
**kwargs
)
app = expr.apply
reductions = [
compute(
val,
data,
post_compute=None,
return_type='native',
).label(name)
for val, name in zip(app.values, app.fields)
]
froms = list(unique(chain(get_all_froms(grouper),
concat(map(get_all_froms, reductions)))))
inner_cols = list(getattr(grouper, 'inner_columns', [grouper]))
grouper_cols = inner_cols[:]
inner_cols.extend(concat(
getattr(getattr(r, 'element', None), 'inner_columns', [r])
for r in reductions
))
wheres = unify_wheres([grouper] + reductions)
sel = unify_froms(sa.select(inner_cols, whereclause=wheres), froms)
return sel.group_by(*grouper_cols)
def compute_up(expr, data, scope=None, **kwargs):
data = lower_column(data)
grouper = compute(
expr.grouper,
scope,
post_compute=False,
return_type='native',
**kwargs
)
app = expr.apply
reductions = [
compute(
val,
data,
post_compute=None,
return_type='native',
).label(name)
for val, name in zip(app.values, app.fields)
]
froms = list(unique(chain(get_all_froms(grouper),
concat(map(get_all_froms, reductions)))))
inner_cols = list(getattr(grouper, 'inner_columns', [grouper]))
grouper_cols = inner_cols[:]
inner_cols.extend(concat(
getattr(getattr(r, 'element', None), 'inner_columns', [r])
for r in reductions
))
wheres = unify_wheres([grouper] + reductions)
sel = unify_froms(sa.select(inner_cols, whereclause=wheres), froms)
return sel.group_by(*grouper_cols)
def compute_up(expr, data, **kwargs):
if not valid_grouper(expr.grouper):
raise TypeError("Grouper must have a non-nested record or one "
"dimensional collection datashape, "
"got %s of type %r with dshape %s" %
(expr.grouper, type(expr.grouper).__name__,
expr.grouper.dshape))
grouper = get_inner_columns(
compute(
expr.grouper,
data,
post_compute=False,
return_type='native',
),
)
app = expr.apply
reductions = [
compute(
val,
data,
post_compute=False,
return_type='native',
).label(name)
for val, name in zip(app.values, app.fields)
]
return sa.select(grouper + reductions).group_by(*grouper)
def interpose(el, seq):
""" Introduce element between each pair of elements in seq
>>> list(interpose("a", [1, 2, 3]))
[1, 'a', 2, 'a', 3]
"""
combined = zip(itertools.repeat(el), seq)
return drop(1, concat(combined))
def interpose(el, seq):
""" Introduce element between each pair of elements in seq
>>> list(interpose("a", [1, 2, 3]))
[1, 'a', 2, 'a', 3]
"""
combined = zip(itertools.repeat(el), seq)
return drop(1, concat(combined))
def compute_up(t, s, **kwargs):
scope = {t._child: s}
return sa.select(
compute(
value,
scope,
post_compute=None,
return_type='native',
).label(name) for value, name in zip(t.values, t.fields))
def interpose(el, seq):
""" Introduce element between each pair of elements in seq
>>> list(interpose("a", [1, 2, 3]))
[1, 'a', 2, 'a', 3]
"""
inposed = concat(zip(itertools.repeat(el), seq))
next(inposed)
return inposed
def compute_up(expr, data, **kwargs):
grouper = lower_column(data)
app = expr.apply
if isinstance(app, Reduction):
reductions = [compute(app, data, post_compute=False)]
elif isinstance(app, Summary):
reductions = [compute(val, data, post_compute=None).label(name)
for val, name in zip(app.values, app.fields)]
return sa.select([grouper] + reductions).group_by(grouper)
def keymap(func, d):
""" Apply function to keys of dictionary
>>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
>>> keymap(str.lower, bills) # doctest: +SKIP
{'alice': [20, 15, 30], 'bob': [10, 35]}
See Also:
valmap
"""
return dict(zip(map(func, iterkeys(d)), itervalues(d)))
def keymap(func, d):
""" Apply function to keys of dictionary
>>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
>>> keymap(str.lower, bills) # doctest: +SKIP
{'alice': [20, 15, 30], 'bob': [10, 35]}
See Also:
valmap
"""
return dict(zip(map(func, iterkeys(d)), itervalues(d)))
def compute_up(t, s, **kwargs):
scope = {t._child: s}
return sa.select(
compute(
value,
scope,
post_compute=None,
return_type='native',
).label(name)
for value, name in zip(t.values, t.fields)
)
def valmap(func, d):
""" Apply function to values of dictionary
>>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
>>> valmap(sum, bills) # doctest: +SKIP
{'Alice': 65, 'Bob': 45}
See Also:
keymap
"""
return dict(zip(iterkeys(d), map(func, itervalues(d))))
def valmap(func, d):
""" Apply function to values of dictionary
>>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
>>> valmap(sum, bills) # doctest: +SKIP
{'Alice': 65, 'Bob': 45}
See Also:
keymap
"""
return dict(zip(iterkeys(d), map(func, itervalues(d))))
def compute_up(expr, data, **kwargs):
grouper = lower_column(data)
app = expr.apply
if isinstance(app, Reduction):
reductions = [compute(app, data, post_compute=False)]
elif isinstance(app, Summary):
reductions = [
compute(val, data, post_compute=None).label(name)
for val, name in zip(app.values, app.fields)
]
return sa.select([grouper] + reductions).group_by(grouper)
def compute_up(t, s, scope=None, **kwargs):
d = dict((t._child[c], list(inner_columns(s))[i])
for i, c in enumerate(t._child.fields))
cols = [compute(val, toolz.merge(scope, d), post_compute=None).label(name)
for name, val in zip(t.fields, t.values)]
s = copy(s)
for c in cols:
s.append_column(c)
return s.with_only_columns(cols)
def compute_up(t, s, scope=None, **kwargs):
d = dict((t._child[c], list(inner_columns(s))[i])
for i, c in enumerate(t._child.fields))
cols = [compute(val, toolz.merge(scope, d), post_compute=None).label(name)
for name, val in zip(t.fields, t.values)]
s = copy(s)
for c in cols:
s.append_column(c)
return s.with_only_columns(cols)
def keymap(func, d, factory=dict):
""" Apply function to keys of dictionary
>>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
>>> keymap(str.lower, bills) # doctest: +SKIP
{'alice': [20, 15, 30], 'bob': [10, 35]}
See Also:
valmap
itemmap
"""
rv = factory()
rv.update(zip(map(func, iterkeys(d)), itervalues(d)))
return rv
def keymap(func, d, factory=dict):
""" Apply function to keys of dictionary
>>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
>>> keymap(str.lower, bills) # doctest: +SKIP
{'alice': [20, 15, 30], 'bob': [10, 35]}
See Also:
valmap
itemmap
"""
rv = factory()
rv.update(zip(map(func, iterkeys(d)), itervalues(d)))
return rv
def valmap(func, d, factory=dict):
""" Apply function to values of dictionary
>>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
>>> valmap(sum, bills) # doctest: +SKIP
{'Alice': 65, 'Bob': 45}
See Also:
keymap
itemmap
"""
rv = factory()
rv.update(zip(iterkeys(d), map(func, itervalues(d))))
return rv
def valmap(func, d, factory=dict):
""" Apply function to values of dictionary
>>> bills = {"Alice": [20, 15, 30], "Bob": [10, 35]}
>>> valmap(sum, bills) # doctest: +SKIP
{'Alice': 65, 'Bob': 45}
See Also:
keymap
itemmap
"""
rv = factory()
rv.update(zip(iterkeys(d), map(func, itervalues(d))))
return rv
def sliding_window(n, seq):
""" A sequence of overlapping subsequences
>>> list(sliding_window(2, [1, 2, 3, 4]))
[(1, 2), (2, 3), (3, 4)]
This function creates a sliding window suitable for transformations like
sliding means / smoothing
>>> mean = lambda seq: float(sum(seq)) / len(seq)
>>> list(map(mean, sliding_window(2, [1, 2, 3, 4])))
[1.5, 2.5, 3.5]
"""
return zip(*(collections.deque(itertools.islice(it, i), 0) or it
for i, it in enumerate(itertools.tee(seq, n))))
def sliding_window(n, seq):
""" A sequence of overlapping subsequences
>>> list(sliding_window(2, [1, 2, 3, 4]))
[(1, 2), (2, 3), (3, 4)]
This function creates a sliding window suitable for transformations like
sliding means / smoothing
>>> mean = lambda seq: float(sum(seq)) / len(seq)
>>> list(map(mean, sliding_window(2, [1, 2, 3, 4])))
[1.5, 2.5, 3.5]
"""
return zip(*(collections.deque(itertools.islice(it, i), 0) or it
for i, it in enumerate(itertools.tee(seq, n))))
def load_castra_partition(castra, part, columns, index):
import blosc
# Due to serialization issues, blosc needs to be manually initialized in
# each process.
blosc.init()
df = castra.load_partition(part, columns)
if isinstance(columns, list):
items = df.itertuples(index)
else:
items = df.iteritems() if index else iter(df)
items = list(items)
if items and isinstance(items[0], tuple) and type(items[0]) is not tuple:
names = items[0]._fields
items = [dict(zip(names, item)) for item in items]
return items
def load_castra_partition(castra, part, columns, index):
import blosc
# Due to serialization issues, blosc needs to be manually initialized in
# each process.
blosc.init()
df = castra.load_partition(part, columns)
if isinstance(columns, list):
items = df.itertuples(index)
else:
items = df.iteritems() if index else iter(df)
items = list(items)
if items and isinstance(items[0], tuple) and type(items[0]) is not tuple:
names = items[0]._fields
items = [dict(zip(names, item)) for item in items]
return items
def diff(*seqs, **kwargs):
""" Return those items that differ between sequences
>>> list(diff([1, 2, 3], [1, 2, 10, 100]))
[(3, 10)]
Shorter sequences may be padded with a ``default`` value:
>>> list(diff([1, 2, 3], [1, 2, 10, 100], default=None))
[(3, 10), (None, 100)]
A ``key`` function may also be applied to each item to use during
comparisons:
>>> list(diff(['apples', 'bananas'], ['Apples', 'Oranges'], key=str.lower))
[('bananas', 'Oranges')]
"""
N = len(seqs)
if N == 1 and isinstance(seqs[0], list):
seqs = seqs[0]
N = len(seqs)
if N < 2:
raise TypeError('Too few sequences given (min 2 required)')
default = kwargs.get('default', no_default)
if default == no_default:
iters = zip(*seqs)
else:
iters = zip_longest(*seqs, fillvalue=default)
key = kwargs.get('key', None)
if key is None:
for items in iters:
if items.count(items[0]) != N:
yield items
else:
for items in iters:
vals = tuple(map(key, items))
if vals.count(vals[0]) != N:
yield items
def diff(*seqs, **kwargs):
""" Return those items that differ between sequences
>>> list(diff([1, 2, 3], [1, 2, 10, 100]))
[(3, 10)]
Shorter sequences may be padded with a ``default`` value:
>>> list(diff([1, 2, 3], [1, 2, 10, 100], default=None))
[(3, 10), (None, 100)]
A ``key`` function may also be applied to each item to use during
comparisons:
>>> list(diff(['apples', 'bananas'], ['Apples', 'Oranges'], key=str.lower))
[('bananas', 'Oranges')]
"""
N = len(seqs)
if N == 1 and isinstance(seqs[0], list):
seqs = seqs[0]
N = len(seqs)
if N < 2:
raise TypeError('Too few sequences given (min 2 required)')
default = kwargs.get('default', no_default)
if default == no_default:
iters = zip(*seqs)
else:
iters = zip_longest(*seqs, fillvalue=default)
key = kwargs.get('key', None)
if key is None:
for items in iters:
if items.count(items[0]) != N:
yield items
else:
for items in iters:
vals = tuple(map(key, items))
if vals.count(vals[0]) != N:
yield items
def partition(n, seq, pad=no_pad):
""" Partition sequence into tuples of length n
>>> list(partition(2, [1, 2, 3, 4]))
[(1, 2), (3, 4)]
If the length of ``seq`` is not evenly divisible by ``n``, the final tuple
is dropped if ``pad`` is not specified, or filled to length ``n`` by pad:
>>> list(partition(2, [1, 2, 3, 4, 5]))
[(1, 2), (3, 4)]
>>> list(partition(2, [1, 2, 3, 4, 5], pad=None))
[(1, 2), (3, 4), (5, None)]
See Also:
partition_all
"""
args = [iter(seq)] * n
if pad is no_pad:
return zip(*args)
else:
return zip_longest(*args, fillvalue=pad)
def partition(n, seq, pad=no_pad):
""" Partition sequence into tuples of length n
>>> list(partition(2, [1, 2, 3, 4]))
[(1, 2), (3, 4)]
If the length of ``seq`` is not evenly divisible by ``n``, the final tuple
is dropped if ``pad`` is not specified, or filled to length ``n`` by pad:
>>> list(partition(2, [1, 2, 3, 4, 5]))
[(1, 2), (3, 4)]
>>> list(partition(2, [1, 2, 3, 4, 5], pad=None))
[(1, 2), (3, 4), (5, None)]
See Also:
partition_all
"""
args = [iter(seq)] * n
if pad is no_pad:
return zip(*args)
else:
return zip_longest(*args, fillvalue=pad)
def mean_aggregate(x):
totals, counts = list(zip(*x))
return 1.0 * sum(totals) / sum(counts)
def var_aggregate(x):
squares, totals, counts = list(zip(*x))
x2, x, n = float(sum(squares)), float(sum(totals)), sum(counts)
result = (x2 / n) - (x / n)**2
return result * n / (n - ddof)
def var_aggregate(x):
squares, totals, counts = list(zip(*x))
x2, x, n = float(sum(squares)), float(sum(totals)), sum(counts)
result = (x2 / n) - (x / n)**2
return result * n / (n - ddof)
def mean_aggregate(x):
totals, counts = list(zip(*x))
return 1.0 * sum(totals) / sum(counts)
def compute(t, seq):
seq1, seq2 = itertools.tee(seq)
parent = compute(t.parent, seq1)
predicate = compute(t.predicate, seq2)
return (x for x, tf in zip(parent, predicate)
if tf)
