def search(self, start, stop=None):
results = _search_tree(self.tree, start, stop, self.include_stop)
if len(results) == 0:
return None
elif len(results) > 1 and self.strict:
raise DuplicateKeyError((start, stop))
else:
return results[0].data
def recordlookupone(table, key, dictionary=None, strict=False):
"""
Load a dictionary with data from the given table, mapping to record objects,
assuming there is at most one row for each key.
"""
if dictionary is None:
dictionary = dict()
it = iter(table)
hdr = next(it)
flds = list(map(text_type, hdr))
keyindices = asindices(hdr, key)
assert len(keyindices) > 0, 'no key selected'
getkey = operator.itemgetter(*keyindices)
for row in it:
k = getkey(row)
if strict and k in dictionary:
raise DuplicateKeyError(k)
elif k not in dictionary:
d = Record(row, flds)
dictionary[k] = d
return dictionary
def lookupone(table, key, value=None, dictionary=None, strict=False):
"""
Load a dictionary with data from the given table, assuming there is
at most one value for each key. E.g.::
>>> import petl as etl
>>> table1 = [['foo', 'bar'],
... ['a', 1],
... ['b', 2],
... ['b', 3]]
>>> # if the specified key is not unique and strict=False (default),
... # the first value wins
... lkp = etl.lookupone(table1, 'foo', 'bar')
>>> lkp['a']
1
>>> lkp['b']
2
>>> # if the specified key is not unique and strict=True, will raise
... # DuplicateKeyError
... try:
... lkp = etl.lookupone(table1, 'foo', strict=True)
... except etl.errors.DuplicateKeyError as e:
... print(e)
...
duplicate key: 'b'
>>> # compound keys are supported
... table2 = [['foo', 'bar', 'baz'],
... ['a', 1, True],
... ['b', 2, False],
... ['b', 3, True],
... ['b', 3, False]]
>>> lkp = etl.lookupone(table2, ('foo', 'bar'), 'baz')
>>> lkp[('a', 1)]
True
>>> lkp[('b', 2)]
False
>>> lkp[('b', 3)]
True
>>> # data can be loaded into an existing dictionary-like
... # object, including persistent dictionaries created via the
... # shelve module
... import shelve
>>> lkp = shelve.open('example.dat', flag='n')
>>> lkp = etl.lookupone(table1, 'foo', 'bar', lkp)
>>> lkp.close()
>>> lkp = shelve.open('example.dat', flag='r')
>>> lkp['a']
1
>>> lkp['b']
2
"""
if dictionary is None:
dictionary = dict()
it = iter(table)
hdr = next(it)
flds = list(map(text_type, hdr))
if value is None:
value = flds
keyindices = asindices(hdr, key)
assert len(keyindices) > 0, 'no key selected'
valueindices = asindices(hdr, value)
assert len(valueindices) > 0, 'no value selected'
getkey = operator.itemgetter(*keyindices)
getvalue = operator.itemgetter(*valueindices)
for row in it:
k = getkey(row)
if strict and k in dictionary:
raise DuplicateKeyError(k)
elif k not in dictionary:
v = getvalue(row)
dictionary[k] = v
return dictionary
def lookupone(table, key, value=None, dictionary=None, strict=False):
"""
Load a dictionary with data from the given table, assuming there is
at most one value for each key. E.g.::
>>> import petl as etl
>>> table1 = [['foo', 'bar'],
... ['a', 1],
... ['b', 2],
... ['b', 3]]
>>> # if the specified key is not unique and strict=False (default),
... # the first value wins
... lkp = etl.lookupone(table1, 'foo', 'bar')
>>> lkp['a']
1
>>> lkp['b']
2
>>> # if the specified key is not unique and strict=True, will raise
... # DuplicateKeyError
... try:
... lkp = etl.lookupone(table1, 'foo', strict=True)
... except etl.errors.DuplicateKeyError as e:
... print(e)
...
duplicate key: 'b'
>>> # compound keys are supported
... table2 = [['foo', 'bar', 'baz'],
... ['a', 1, True],
... ['b', 2, False],
... ['b', 3, True],
... ['b', 3, False]]
>>> lkp = etl.lookupone(table2, ('foo', 'bar'), 'baz')
>>> lkp[('a', 1)]
True
>>> lkp[('b', 2)]
False
>>> lkp[('b', 3)]
True
>>> # data can be loaded into an existing dictionary-like
... # object, including persistent dictionaries created via the
... # shelve module
... import shelve
>>> lkp = shelve.open('example.dat', flag='n')
>>> lkp = etl.lookupone(table1, 'foo', 'bar', lkp)
>>> lkp.close()
>>> lkp = shelve.open('example.dat', flag='r')
>>> lkp['a']
1
>>> lkp['b']
2
"""
if dictionary is None:
dictionary = dict()
# setup
it, getkey, getvalue = _setup_lookup(table, key, value)
# build lookup dictionary
for row in it:
k = getkey(row)
if strict and k in dictionary:
raise DuplicateKeyError(k)
elif k not in dictionary:
v = getvalue(row)
dictionary[k] = v
return dictionary