# overlap coefficient join
[docs]def overlap_coefficient_join(ltable, rtable,
l_key_attr, r_key_attr,
l_join_attr, r_join_attr,
tokenizer, threshold, comp_op='>=',
allow_empty=True, allow_missing=False,
l_out_attrs=None, r_out_attrs=None,
l_out_prefix='l_', r_out_prefix='r_',
out_sim_score=True, n_jobs=1, show_progress=True):
"""Join two tables using overlap coefficient.
For two sets X and Y, the overlap coefficient between them is given by:
:math:`overlap\\_coefficient(X, Y) = \\frac{|X \\cap Y|}{\\min(|X|, |Y|)}`
In the case where one of X and Y is an empty set and the other is a
non-empty set, we define their overlap coefficient to be 0. In the case
where both X and Y are empty sets, we define their overlap coefficient to
be 1.
Finds tuple pairs from left table and right table such that the overlap
coefficient between the join attributes satisfies the condition on input
threshold. For example, if the comparison operator is '>=', finds tuple
pairs whose overlap coefficient between the strings that are the values of
the join attributes is greater than or equal to the input threshold, as
specified in "threshold".
Args:
ltable (DataFrame): left input table.
rtable (DataFrame): right input table.
l_key_attr (string): key attribute in left table.
r_key_attr (string): key attribute in right table.
l_join_attr (string): join attribute in left table.
r_join_attr (string): join attribute in right table.
tokenizer (Tokenizer): tokenizer to be used to tokenize join
attributes.
threshold (float): overlap coefficient threshold to be satisfied.
comp_op (string): comparison operator. Supported values are '>=', '>'
and '=' (defaults to '>=').
allow_empty (boolean): flag to indicate whether tuple pairs with empty
set of tokens in both the join attributes should be included in the
output (defaults to True).
allow_missing (boolean): flag to indicate whether tuple pairs with
missing value in at least one of the join attributes should be
included in the output (defaults to False). If this flag is set to
True, a tuple in ltable with missing value in the join attribute
will be matched with every tuple in rtable and vice versa.
l_out_attrs (list): list of attribute names from the left table to be
included in the output table (defaults to None).
r_out_attrs (list): list of attribute names from the right table to be
included in the output table (defaults to None).
l_out_prefix (string): prefix to be used for the attribute names coming
from the left table, in the output table (defaults to 'l\_').
r_out_prefix (string): prefix to be used for the attribute names coming
from the right table, in the output table (defaults to 'r\_').
out_sim_score (boolean): flag to indicate whether similarity score
should be included in the output table (defaults to True). Setting
this flag to True will add a column named '_sim_score' in the
output table. This column will contain the similarity scores for the
tuple pairs in the output.
n_jobs (int): number of parallel jobs to use for the computation
(defaults to 1). If -1 is given, all CPUs are used. If 1 is given,
no parallel computing code is used at all, which is useful for
debugging. For n_jobs below -1, (n_cpus + 1 + n_jobs) are used
(where n_cpus is the total number of CPUs in the machine). Thus for
n_jobs = -2, all CPUs but one are used. If (n_cpus + 1 + n_jobs)
becomes less than 1, then no parallel computing code will be used
(i.e., equivalent to the default).
show_progress (boolean): flag to indicate whether task progress should
be displayed to the user (defaults to True).
Returns:
An output table containing tuple pairs that satisfy the join
condition (DataFrame).
"""
from py_stringsimjoin import __use_cython__
if __use_cython__:
from py_stringsimjoin.join.overlap_coefficient_join_cy import overlap_coefficient_join_cy
return overlap_coefficient_join_cy(ltable, rtable,
l_key_attr, r_key_attr,
l_join_attr, r_join_attr,
tokenizer, threshold, comp_op,
allow_empty, allow_missing,
l_out_attrs, r_out_attrs,
l_out_prefix, r_out_prefix,
out_sim_score, n_jobs, show_progress)
else:
from py_stringsimjoin.join.overlap_coefficient_join_py import overlap_coefficient_join_py
return overlap_coefficient_join_py(ltable, rtable,
l_key_attr, r_key_attr,
l_join_attr, r_join_attr,
tokenizer, threshold, comp_op,
allow_empty, allow_missing,
l_out_attrs, r_out_attrs,
l_out_prefix, r_out_prefix,
out_sim_score, n_jobs, show_progress)