def groupcountdistinctvalues(table, key, value):
"""Group by the `key` field then count the number of distinct values in the
`value` field."""
s1 = cut(table, key, value)
s2 = distinct(s1)
s3 = aggregate(s2, key, len)
return s3
def groupcountdistinctvalues(table, key, value):
"""Group by the `key` field then count the number of distinct values in the
`value` field."""
s1 = cut(table, key, value)
s2 = distinct(s1)
s3 = aggregate(s2, key, len)
return s3
def test_key_distinct_2():
# test for https://github.com/alimanfoo/petl/issues/318
tbl = (('a', 'b'), ('x', '1'), ('x', '3'), ('y', '1'), (None, None))
result = distinct(tbl, key='b')
expect = (('a', 'b'), (None, None), ('x', '1'), ('x', '3'))
ieq(expect, result)
def test_distinct_count():
table = (('foo', 'bar', 'baz'), ('A', 1, 2), ('B', '2', '3.4'),
('B', '2', '3.4'), ('D', 4, 12.3))
result = distinct(table, count='count')
expect = (('foo', 'bar', 'baz', 'count'), ('A', 1, 2, 1),
('B', '2', '3.4', 2), ('D', 4, 12.3, 1))
ieq(expect, result)
def test_distinct():
table = (('foo', 'bar', 'baz'), ('A', 1, 2), ('B', '2', '3.4'),
('B', '2', '3.4'), ('D', 4, 12.3))
result = distinct(table)
expect = (('foo', 'bar', 'baz'), ('A', 1, 2), ('B', '2', '3.4'), ('D', 4,
12.3))
ieq(expect, result)
def test_key_distinct():
table = (('foo', 'bar', 'baz'), (None, None, None), ('A', 1, 2),
('B', '2', '3.4'), ('B', '2', '5'), ('D', 4, 12.3))
result = distinct(table, key='foo')
expect = (('foo', 'bar', 'baz'), (None, None, None), ('A', 1, 2),
('B', '2', '3.4'), ('D', 4, 12.3))
ieq(expect, result)
def test_key_distinct_2():
# test for https://github.com/alimanfoo/petl/issues/318
tbl = (('a', 'b'),
('x', '1'),
('x', '3'),
('y', '1'))
result = distinct(tbl, key='b')
expect = (('a', 'b'),
('x', '1'),
('x', '3'))
ieq(expect, result)
def test_key_distinct_count():
table = (('foo', 'bar', 'baz'),
('A', 1, 2),
('B', '2', '3.4'),
('B', '2', '5'),
('D', 4, 12.3))
result = distinct(table, key='foo', count='count')
expect = (('foo', 'bar', 'baz', 'count'),
('A', 1, 2, 1),
('B', '2', '3.4', 2),
('D', 4, 12.3, 1))
ieq(expect, result)
def test_distinct():
table = (('foo', 'bar', 'baz'),
('A', 1, 2),
('B', '2', '3.4'),
('B', '2', '3.4'),
('D', 4, 12.3))
result = distinct(table)
expect = (('foo', 'bar', 'baz'),
('A', 1, 2),
('B', '2', '3.4'),
('D', 4, 12.3))
ieq(expect, result)
def unjoin(table, value, key=None, autoincrement=(1, 1), presorted=False,
buffersize=None, tempdir=None, cache=True):
"""
Split a table into two tables by reversing an inner join.
E.g., if the join key is present in the table::
>>> from petl import look, unjoin
>>> look(table1)
+-------+-------+----------+
| 'foo' | 'bar' | 'baz' |
+=======+=======+==========+
| 'A' | 1 | 'apple' |
+-------+-------+----------+
| 'B' | 1 | 'apple' |
+-------+-------+----------+
| 'C' | 2 | 'orange' |
+-------+-------+----------+
>>> table2, table3 = unjoin(table1, 'baz', key='bar')
>>> look(table2)
+-------+-------+
| 'foo' | 'bar' |
+=======+=======+
| 'A' | 1 |
+-------+-------+
| 'B' | 1 |
+-------+-------+
| 'C' | 2 |
+-------+-------+
>>> look(table3)
+-------+----------+
| 'bar' | 'baz' |
+=======+==========+
| 1 | 'apple' |
+-------+----------+
| 2 | 'orange' |
+-------+----------+
An integer join key can also be reconstructed, e.g.::
>>> look(table4)
+-------+----------+
| 'foo' | 'bar' |
+=======+==========+
| 'A' | 'apple' |
+-------+----------+
| 'B' | 'apple' |
+-------+----------+
| 'C' | 'orange' |
+-------+----------+
>>> table5, table6 = unjoin(table4, 'bar')
>>> look(table5)
+-------+----------+
| 'foo' | 'bar_id' |
+=======+==========+
| 'A' | 1 |
+-------+----------+
| 'B' | 1 |
+-------+----------+
| 'C' | 2 |
+-------+----------+
>>> look(table6)
+------+----------+
| 'id' | 'bar' |
+======+==========+
| 1 | 'apple' |
+------+----------+
| 2 | 'orange' |
+------+----------+
.. versionadded:: 0.12
"""
if key is None:
# first sort the table by the value field
if presorted:
tbl_sorted = table
else:
tbl_sorted = sort(table, value, buffersize=buffersize,
tempdir=tempdir, cache=cache)
# on the left, return the original table but with the value field
# replaced by an incrementing integer
left = ConvertToIncrementingCounterView(tbl_sorted, value,
autoincrement)
# on the right, return a new table with distinct values from the
# given field
right = EnumerateDistinctView(tbl_sorted, value, autoincrement)
else:
# on the left, return distinct rows from the original table
# with the value field cut out
left = distinct(cutout(table, value))
# on the right, return distinct rows from the original table
# with all fields but the key and value cut out
right = distinct(cut(table, key, value))
return left, right
def unjoin(table,
value,
key=None,
autoincrement=(1, 1),
presorted=False,
buffersize=None,
tempdir=None,
cache=True):
"""
Split a table into two tables by reversing an inner join. E.g.::
>>> import petl as etl
>>> # join key is present in the table
... table1 = (('foo', 'bar', 'baz'),
... ('A', 1, 'apple'),
... ('B', 1, 'apple'),
... ('C', 2, 'orange'))
>>> table2, table3 = etl.unjoin(table1, 'baz', key='bar')
>>> table2
+-----+-----+
| foo | bar |
+=====+=====+
| 'A' | 1 |
+-----+-----+
| 'B' | 1 |
+-----+-----+
| 'C' | 2 |
+-----+-----+
>>> table3
+-----+----------+
| bar | baz |
+=====+==========+
| 1 | 'apple' |
+-----+----------+
| 2 | 'orange' |
+-----+----------+
>>> # an integer join key can also be reconstructed
... table4 = (('foo', 'bar'),
... ('A', 'apple'),
... ('B', 'apple'),
... ('C', 'orange'))
>>> table5, table6 = etl.unjoin(table4, 'bar')
>>> table5
+-----+--------+
| foo | bar_id |
+=====+========+
| 'A' | 1 |
+-----+--------+
| 'B' | 1 |
+-----+--------+
| 'C' | 2 |
+-----+--------+
>>> table6
+----+----------+
| id | bar |
+====+==========+
| 1 | 'apple' |
+----+----------+
| 2 | 'orange' |
+----+----------+
The `autoincrement` parameter controls how an integer join key is
reconstructed, and should be a tuple of (`start`, `step`).
"""
if key is None:
# first sort the table by the value field
if presorted:
tbl_sorted = table
else:
tbl_sorted = sort(table,
value,
buffersize=buffersize,
tempdir=tempdir,
cache=cache)
# on the left, return the original table but with the value field
# replaced by an incrementing integer
left = ConvertToIncrementingCounterView(tbl_sorted, value,
autoincrement)
# on the right, return a new table with distinct values from the
# given field
right = EnumerateDistinctView(tbl_sorted, value, autoincrement)
else:
# on the left, return distinct rows from the original table
# with the value field cut out
left = distinct(cutout(table, value))
# on the right, return distinct rows from the original table
# with all fields but the key and value cut out
right = distinct(cut(table, key, value))
return left, right
def unjoin(table, value, key=None, autoincrement=(1, 1), presorted=False,
buffersize=None, tempdir=None, cache=True):
"""
Split a table into two tables by reversing an inner join. E.g.::
>>> import petl as etl
>>> # join key is present in the table
... table1 = (('foo', 'bar', 'baz'),
... ('A', 1, 'apple'),
... ('B', 1, 'apple'),
... ('C', 2, 'orange'))
>>> table2, table3 = etl.unjoin(table1, 'baz', key='bar')
>>> table2
+-----+-----+
| foo | bar |
+=====+=====+
| 'A' | 1 |
+-----+-----+
| 'B' | 1 |
+-----+-----+
| 'C' | 2 |
+-----+-----+
>>> table3
+-----+----------+
| bar | baz |
+=====+==========+
| 1 | 'apple' |
+-----+----------+
| 2 | 'orange' |
+-----+----------+
>>> # an integer join key can also be reconstructed
... table4 = (('foo', 'bar'),
... ('A', 'apple'),
... ('B', 'apple'),
... ('C', 'orange'))
>>> table5, table6 = etl.unjoin(table4, 'bar')
>>> table5
+-----+--------+
| foo | bar_id |
+=====+========+
| 'A' | 1 |
+-----+--------+
| 'B' | 1 |
+-----+--------+
| 'C' | 2 |
+-----+--------+
>>> table6
+----+----------+
| id | bar |
+====+==========+
| 1 | 'apple' |
+----+----------+
| 2 | 'orange' |
+----+----------+
The `autoincrement` parameter controls how an integer join key is
reconstructed, and should be a tuple of (`start`, `step`).
"""
if key is None:
# first sort the table by the value field
if presorted:
tbl_sorted = table
else:
tbl_sorted = sort(table, value, buffersize=buffersize,
tempdir=tempdir, cache=cache)
# on the left, return the original table but with the value field
# replaced by an incrementing integer
left = ConvertToIncrementingCounterView(tbl_sorted, value,
autoincrement)
# on the right, return a new table with distinct values from the
# given field
right = EnumerateDistinctView(tbl_sorted, value, autoincrement)
else:
# on the left, return distinct rows from the original table
# with the value field cut out
left = distinct(cutout(table, value))
# on the right, return distinct rows from the original table
# with all fields but the key and value cut out
right = distinct(cut(table, key, value))
return left, right
