def test3_nocaching(self):
# Not all attributes (here "adresse") are present for all of the URIs.
input = pd.DataFrame({
'uris': [
'http://dbpedia.org/resource/Berlin',
'http://dbpedia.org/resource/Darmstadt',
'http://dbpedia.org/resource/London',
'http://dbpedia.org/resource/Munich'
]
})
query = "SELECT DISTINCT ?uri ?adresse ?lat WHERE {VALUES (?uri) {(<**URI**>)} ?uri dbp:adresse ?adresse. ?uri geo:lat ?lat} ORDER BY ?adresse LIMIT 2"
result = uri_querier(input, "uris", query, caching=False)
expected_result_df = pd.DataFrame({
'uri': [
'http://dbpedia.org/resource/Darmstadt',
'http://dbpedia.org/resource/Darmstadt',
'http://dbpedia.org/resource/Munich',
'http://dbpedia.org/resource/Munich'
],
'adresse': ['Luisenplatz 5', '64283', 'Marienplatz 8', '80331'],
'lat': [49.8667, 49.8667, 48.1333, 48.1333]
})
pd.testing.assert_frame_equal(result,
expected_result_df,
check_like=True)
def test4_brokenuris(self):
# Not all attributes (here "adresse") are present for all of the URIs.
input = pd.DataFrame({
'uris': [
'https://www.dd', 'www.google.de', 'https://www.google.de',
'http://dbpedia.org/resource/Munich', np.nan
]
})
query = "SELECT DISTINCT ?uri ?adresse ?lat WHERE {VALUES (?uri) {(<**URI**>)} ?uri dbp:adresse ?adresse. ?uri geo:lat ?lat} ORDER BY ?adresse LIMIT 2"
with pytest.warns(UserWarning) as record:
result = uri_querier(input, "uris", query, progress=True)
assert len(record) == 3
assert record[0].message.args[
0] == "https://www.dd is not a valid URI."
assert record[1].message.args[
0] == "www.google.de might not be a valid URI."
assert record[2].message.args[
0] == "https://www.google.de might not be dereferencable."
expected_result_df = pd.DataFrame({
'uri': [
'http://dbpedia.org/resource/Munich',
'http://dbpedia.org/resource/Munich'
],
'adresse': ['Marienplatz 8', '80331'],
'lat': [48.1333, 48.1333]
})
pd.testing.assert_frame_equal(result,
expected_result_df,
check_like=True)
def hierarchy_graph_generator(
col,
hierarchy_relation="http://www.w3.org/2000/01/rdf-schema#subClassOf",
max_hierarchy_depth=None,
endpoint=DBpedia,
uri_data_model=False,
progress=False,
caching=True):
"""Computes a hierarchy graph from an original set of features, where
directed edges symbolise a hierarchy relation from subclass to superclass.
Args:
col (pd.Series): The classes/categories for which the hierarchy graph
is generated.
hierarchy_relation (str, optional): The hierarchy relation to be used.
Defaults to "http://www.w3.org/2000/01/rdf-schema#subClassOf".
max_hierarchy_depth (int, optional): Number of jumps in hierarchy. If
None, transitive jumps are used. Defaults to None.
endpoint (Endpoint, optional): Link to the SPARQL endpoint that should
be queried. Defaults to DBpedia.
uri_data_model (bool, optional): whether to use sparql querier or the
uri data model. Defaults to False.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process (if
"uri_data_model" = True). Defaults to False.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off.
Returns:
nx.DirectedGraph: Graph where edges point to direct superclasses of
nodes.
"""
# warn if wrong configurations are used and correct them
cond_subclass = hierarchy_relation ==\
"http://www.w3.org/2000/01/rdf-schema#subClassOf"
if cond_subclass and max_hierarchy_depth:
warnings.warn("""If you use subClass with a maximum hierarchy depth,
meaningless superclasses are generated.
Max_hierarchy_depth is set to None instead""")
max_hierarchy_depth = None
cond_broader= hierarchy_relation ==\
"http://www.w3.org/2004/02/skos/core#broader"
if cond_broader and max_hierarchy_depth is None:
warnings.warn("""Transitive superclass generation does not work for
categories. Max_hierarchy_depth is set to 1. For higher depths, set
max_hierarchy_depth to a higher integer""")
max_hierarchy_depth = 1
# Initialise the graph
DG = nx.DiGraph()
# if column contains only missings return empty graph
if col.isna().all():
return DG
current_level = col.copy()
# in this case the query contains all future hierarchy levels and queries
# them directly
if max_hierarchy_depth and not uri_data_model:
query = hierarchy_query_creator(col, hierarchy_relation,
max_hierarchy_depth, uri_data_model)
results = endpoint_wrapper(query,
endpoint,
return_XML=True,
caching=caching)
DG, _ = create_graph_from_raw(DG, results, max_hierarchy_depth, None,
uri_data_model)
# here the "broader" steps have to be added sequentially from level to
# level until the max_hierarchy_depth is reached
elif max_hierarchy_depth and uri_data_model:
hierarchy_level = 0
while not current_level.empty and hierarchy_level < max_hierarchy_depth:
query = hierarchy_query_creator(current_level, hierarchy_relation,
max_hierarchy_depth,
uri_data_model)
temp_frame = pd.DataFrame(current_level)
results = uri_querier(temp_frame,
current_level.name,
query,
progress=progress,
caching=caching)
current_level = list()
DG, current_level = create_graph_from_raw(DG, results,
max_hierarchy_depth,
current_level,
uri_data_model)
hierarchy_level += 1
# iteratively loop from hierarchy level to hierarchy level until no
# more superclasses are found --> transitive without maximum
else:
while not current_level.empty:
query = hierarchy_query_creator(current_level, hierarchy_relation,
max_hierarchy_depth,
uri_data_model)
if uri_data_model:
temp_frame = pd.DataFrame(current_level)
results = uri_querier(temp_frame,
current_level.name,
query,
progress=progress,
caching=caching)
else:
results = endpoint_wrapper(query,
endpoint,
return_XML=True,
caching=caching)
current_level = list()
DG, current_level = create_graph_from_raw(DG, results,
max_hierarchy_depth,
current_level,
uri_data_model)
# Find cycles and break them
while not nx.is_directed_acyclic_graph(DG):
try:
cycle = nx.find_cycle(DG)
backwards_path = cycle[1]
DG.remove_edge(*backwards_path)
except nx.NetworkXNoCycle:
pass
return DG
def label_schema_matching(df,
endpoint=DBpedia,
uri_data_model=False,
to_lowercase=True,
remove_prefixes=True,
remove_punctuation=True,
prefix_threshold=1,
progress=True,
caching=True):
"""A schema matching method by checking for attribute -- rdfs:label between
links.
Args:
df (pd.DataFrame): The dataframe where matching attributes are supposed
to be found.
endpoint (Endpoint, optional): SPARQL Endpoint to be queried. Defaults
to DBpedia.
uri_data_model (bool, optional): If enabled, the URI is directly
queried instead of a SPARQL endpoint. Defaults to False.
to_lowercase (bool, optional): Converts queried strings to lowercase.
Defaults to True.
remove_prefixes (bool, optional): Removes prefices of queried strings.
Defaults to True.
remove_punctuation (bool, optional): Removes punctuation from queried
strings. Defaults to True.
prefix_threshold (int, optional): The number of occurences after which
a prefix is considered "common". Defaults to 1.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process (if
"uri_data_model" = True). Defaults to True.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: Two columns with matching links and a third column with the overlapped label.
"""
matches = pd.DataFrame(columns=["uri_1", "uri_2", "same_label"])
# Get URIs from the column names
cat_cols = [col for col in df.columns if re.findall("https*:", col)]
cat_cols_stripped = [
re.sub(r"^.*http://", "http://", col) for col in cat_cols
]
# transform attributes to sparql values list form
values = "(<" + pd.Series(cat_cols_stripped).str.cat(sep=">) (<") + ">) "
if uri_data_model:
# Query these URIs for the label
query = "SELECT ?value ?o WHERE {VALUES (?value) {(<**URI**>)} ?value rdfs:label ?o. FILTER (lang(?o) = 'en') }"
labels = uri_querier(
pd.DataFrame(cat_cols_stripped),
0,
query,
progress=progress,
caching=caching).drop_duplicates().set_index("value")
else:
query = "SELECT ?value ?o WHERE {VALUES (?value) {" + values + \
"} ?value rdfs:label ?o. FILTER (lang(?o) = 'en') }"
# query the equivalent classes/properties
labels = endpoint_wrapper(query, endpoint,
caching=caching).reset_index(drop=True)
if labels.empty:
return matches
# Get common prefixes
common_prefixes = get_common_prefixes(labels, prefix_threshold)
# Clean the results (i.e. the labels)
labels["o"] = labels["o"].apply(lambda x: clean_string(
x, common_prefixes, to_lowercase, remove_prefixes, remove_punctuation))
# Create a dictionary
if labels.index.name == "value":
labels.reset_index(inplace=True)
labels_dict = labels.set_index("value").T.to_dict("list")
#check if there are no matches
tmp = set()
for v in labels_dict.values():
tmp.update(v)
if len(labels_dict) == len(tmp):
combinations = list(itertools.combinations(cat_cols_stripped, 2))
combinations_sorted = [sorted(x) for x in combinations]
matches = pd.DataFrame(combinations_sorted, columns=["uri_1", "uri_2"])
matches["same_label"] = 0
return matches
else:
# Combine the uris that have the same labels into a DataFrame
new_labels_dict = collections.defaultdict(list)
for key, values in labels_dict.items():
for i in values:
new_labels_dict[i].append(key)
df_labels = pd.DataFrame(list(new_labels_dict.values()),
columns=["uri_1", "uri_2"])
#df_labels["same_label"] = pd.DataFrame(list(new_labels_dict.keys()))
df_labels.dropna(inplace=True)
# restrict the order of uris in one row
for _, row in df_labels.iterrows():
new_match = {
"uri_1": min(row["uri_1"], row["uri_2"]),
"uri_2": max(row["uri_1"], row["uri_2"]),
"same_label": 1
}
matches = matches.append(new_match, ignore_index=True)
# Get back the uris that are not quired by rdfs:label and turn df into dict
no_label = pd.DataFrame({
"value":
[x for x in cat_cols_stripped if x not in list(labels["value"])],
"o":
np.nan
})
labels = labels.append(no_label, ignore_index=True)
full_labels_dict = labels.set_index("value").T.to_dict("list")
# Create all unique combinations from the URIs, order them alphabetically and turn them into a DataFrame
combinations = list(itertools.combinations(full_labels_dict.keys(), 2))
combinations_sorted = [sorted(x) for x in combinations]
result = pd.DataFrame(combinations_sorted, columns=["uri_1", "uri_2"])
# merged with the non_matched combinations and drop duplicates
for _, row in result.iterrows():
new_match = {
"uri_1": min(row["uri_1"], row["uri_2"]),
"uri_2": max(row["uri_1"], row["uri_2"]),
"same_label": 0
}
matches = matches.append(new_match, ignore_index=True)
matches.drop_duplicates(subset=["uri_1", "uri_2"],
inplace=True,
ignore_index=True)
return matches
def sameas_linker(
df, column, new_attribute_name="new_link", progress=True, endpoint=DBpedia,
result_filter=None, uri_data_model=False, bundled_mode=True,
prefix_lookup=False, caching=True):
"""Function that takes URIs from a column of a DataFrame and queries a
given SPARQL endpoint for ressources which are connected to these URIs via
owl:sameAs. Found ressources are added as new columns to the dataframe and
the dataframe is returned.
Args:
df (pd.DataFrame): Dataframe to which links are added.
column (str): Name of the column for whose entities links should be
found.
new_attribute_name (str, optional): Name / prefix of the column(s)
containing the found links. Defaults to "new_link".
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process (if
"uri_data_model" = True). Defaults to True.
endpoint (Endpoint, optional): SPARQL Endpoint to be queried; ignored
when "uri_data_model" = True. Defaults to DBpedia.
result_filter (list, optional): A list filled with regexes (as strings)
to filter the results. Defaults to None.
uri_data_model (bool, optional): If enabled, the URI is directly
queried instead of a SPARQL endpoint. Defaults to False.
bundled_mode (bool, optional): If True, all necessary queries are
boundled into one querie (using the VALUES method). - Requires a
SPARQL 1.1 implementation!. Defaults to True.
prefix_lookup (bool/str/dict, optional):
True: Namespaces of prefixes will be looked up at
prefix.cc and added to the sparql query.
str: User provides the path to a json-file with
prefixes and namespaces.
dict: User provides a dictionary with prefixes and
namespaces.
Defaults to False.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: Returns dataframe with (a) new column(s) containing the
found ressources.
"""
df = df.copy()
if bundled_mode and not uri_data_model:
values = " ( <"+df[column].str.cat(sep="> ) ( <")+"> ) "
query = " SELECT DISTINCT ?value ?sameas_uris WHERE {VALUES (?value) {" + \
values+"} ?value owl:sameAs ?sameas_uris . "
if result_filter != None:
query = query + \
"FILTER("+regex_string_generator("?sameas_uris", result_filter)+") "
query = query+"}"
result_df = endpoint_wrapper(
query, endpoint, prefix_lookup=prefix_lookup, caching=caching).drop_duplicates()
else:
result_df = pd.DataFrame()
if uri_data_model:
query = " SELECT DISTINCT ?value ?sameas_uris WHERE {VALUES (?value) {(<**URI**>)} ?value owl:sameAs ?sameas_uris . "
if result_filter != None:
query = query + \
"FILTER("+regex_string_generator("str(?sameas_uris)",
result_filter)+") "
query = query+"}"
result_df = uri_querier(
df, column, query, prefix_lookup=prefix_lookup, progress=progress, caching=caching)
else:
if progress:
iterator = tqdm(df[column].iteritems(), total=df.shape[0])
else:
iterator = df[column].iteritems()
for uri in iterator:
if pd.isna(uri[1]):
pass
else:
query = " SELECT DISTINCT ?value ?sameas_uris WHERE {?value owl:sameAs ?sameas_uris. FILTER (?value = <"+uri[
1]+">"
if result_filter != None:
query = query + \
" && ("+regex_string_generator("?sameas_uris",
result_filter)+")"
query = query+") }"
result = endpoint_wrapper(query, endpoint, prefix_lookup=prefix_lookup, caching=caching)
result_df = result_df.append(result)
result_df = result_df.rename(
{"callret-0": "value"}, axis="columns").drop_duplicates().reset_index(drop=True)
if result_df.empty:
df[new_attribute_name+"_1"] = np.nan
return df
else:
result_df_grouped = result_df.groupby("value")
result_df_grouped = result_df_grouped["sameas_uris"].apply(
lambda x: pd.Series(x.values)).unstack()
result_df_grouped = result_df_grouped.rename(
columns={i: new_attribute_name+"_{}".format(i + 1) for i in range(result_df_grouped.shape[1])})
df = pd.merge(df, result_df_grouped, left_on=column,
right_on="value", how="outer")
return df
def string_similarity_matching(df,
predicate="rdfs:label",
to_lowercase=True,
remove_prefixes=True,
remove_punctuation=True,
similarity_metric="norm_levenshtein",
prefix_threshold=1,
n=2,
progress=True,
caching=True):
"""Calculates the string similarity from the text field obtained by
querying the attributes for the predicate, by default rdfs:label.
Args:
df (pd.DataFrame): Dataframe where matching attributes are supposed to
be found
predicate (str, optional): Defaults to "rdfs:label".
to_lowercase (bool, optional): converts queried strings to lowercase.
Defaults to True.
remove_prefixes (bool, optional): removes prefices of queried strings.
Defaults to True.
remove_punctuation (bool, optional): removes punctuation from queried
strings. Defaults to True.
similarity_metric (str, optional): norm by which strings are compared.
Defaults to "norm_levenshtein".
prefix_threshold (int, optional): The number of occurences after which
a prefix is considered "common". defaults to 1. n (int, optional):
parameter for n-gram and Jaccard similarities. Defaults to 2.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process. Defaults to
True.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: Two columns with matching links and a third column with
the string similarity score.
"""
# Get URIs from the column names
cat_cols = [col for col in df.columns if re.findall("https*:", col)]
cat_cols_stripped = [
re.sub(r"^.*http://", "http://", col) for col in cat_cols
]
# Query these URIs for the predicate (usually the label)
query = "SELECT ?value ?o WHERE {VALUES (?value) {(<**URI**>)} ?value "
query += predicate + " ?o. FILTER (lang(?o) = 'en') }"
labels = uri_querier(pd.DataFrame(cat_cols_stripped),
0,
query,
progress=progress,
caching=caching).set_index("value")
# Get common prefixes
common_prefixes = get_common_prefixes(labels, prefix_threshold)
# Clean the results (i.e. the labels)
labels["o"] = labels["o"].apply(lambda x: clean_string(
x, common_prefixes, to_lowercase, remove_prefixes, remove_punctuation))
# Create a dictionary that maps the URIs to their result (i.e. label)
labels.reset_index(inplace=True)
no_label = pd.DataFrame({
"value":
[x for x in cat_cols_stripped if x not in list(labels["value"])],
"o":
np.nan
})
labels = labels.append(no_label, ignore_index=True)
labels_dict = labels.set_index("value").T.to_dict("list")
#labels_dict = labels.to_dict(orient="index")
# Create all unique combinations from the URIs, order them alphabetically
# and turn them into a DataFrame
combinations = list(itertools.combinations(labels_dict.keys(), 2))
combinations_sorted = [sorted(x) for x in combinations]
result = pd.DataFrame(combinations_sorted, columns=["uri_1", "uri_2"])
# For each combination in this DataFrame, calculate the string similarity
# of their results (i.e. labels)
if progress:
tqdm.pandas(
desc="String Similarity Matching: Calculate String Similarities")
result["value_string"] = result.progress_apply(
lambda x: calc_string_similarity(x["uri_1"],
x["uri_2"],
labels_dict,
metric=similarity_metric,
n=n),
axis=1)
else:
result["value_string"] = result.apply(lambda x: calc_string_similarity(
x["uri_1"], x["uri_2"
], labels_dict, metric=similarity_metric, n=n),
axis=1)
return result
def relational_matching(df,
endpoints=[DBpedia, WikiData],
uri_data_model=False,
match_score=1,
progress=True,
caching=True):
"""Creates a mapping of matching attributes in the schema by checking for
owl:sameAs, owl:equivalentClass, owl:Equivalent and wdt:P1628 links between
them.
Args:
df (pd.DataFrame): Dataframe where matching attributes are supposed to
be found.
endpoints (list, optional): SPARQL Endpoint to be queried. Defaults to
[DBpedia, WikiData].
uri_data_model (bool, optional): If enabled, the URI is directly queried
instead of a SPARQL endpoint. Defaults to False.
match_score (int, optional): Score of the match: 0 < match_score <= 1.
Defaults to 1.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process (if
"uri_data_model" = True). Defaults to True.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: Two columns with matching links and a third column with
the score, which is always one in case of the relational matching
unless specified otherwise.
"""
matches = pd.DataFrame(columns=["uri_1", "uri_2", "value"])
# determine attribute columns
cat_cols = [col for col in df.columns if re.findall("http:", col)]
cat_cols_stripped = [
re.sub(r"^.*http://", "http://", col) for col in cat_cols
]
if not cat_cols:
return matches
# transform attributes to sparql values list form
values = "(<" + pd.Series(cat_cols_stripped).str.cat(sep=">) (<") + ">) "
if uri_data_model:
# formulate query
query = "PREFIX wdt: <http://www.wikidata.org/prop/direct/>"
query += "SELECT ?value ?object WHERE {VALUES (?value) { (<**URI**>)}"
query += " ?value\
(owl:equivalentProperty|owl:equivalentClass|owl:sameAs|wdt:P1628)\
?object. }"
temp_df = pd.DataFrame(cat_cols_stripped, columns=["values"])
same_cats = uri_querier(temp_df,
"values",
query,
caching=caching,
progress=progress)
if same_cats.empty:
return matches
else:
same_cats = same_cats.drop(
same_cats[same_cats["value"] == same_cats["object"]].index)
else:
if not isinstance(endpoints, list):
endpoints = [endpoints]
same_cats = pd.DataFrame(columns=["value", "object"])
for endpoint in endpoints:
# formulate query
query = "PREFIX wdt: <http://www.wikidata.org/prop/direct/>"
query += "SELECT ?value ?object WHERE {VALUES (?value) {"
query += values
query += "} ?value\
(owl:equivalentProperty|owl:equivalentClass|owl:sameAs|wdt:P1628)\
?object. }"
# query the equivalent classes/properties
query_result = endpoint_wrapper(query, endpoint, caching=caching)
if not query_result.empty:
query_result = query_result.drop_duplicates().\
reset_index(drop=True)
# group equivalent classes/properties for each original attribute
same_cats = same_cats.append(query_result, ignore_index=True)
if same_cats.empty:
return matches
combinations = list(itertools.combinations(cat_cols_stripped, 2))
combinations_sorted = pd.DataFrame([sorted(x) for x in combinations],
columns=["uri_1", "uri_2"])
# detect matches in the attributes
for _, row in same_cats.iterrows():
if row["object"] in cat_cols_stripped:
# if there is a match insert it in alphabetical order into the
# output matches dataframe
new_match = {
"uri_1": min(row["value"], row["object"]),
"uri_2": max(row["value"], row["object"]),
"value": match_score
}
matches = matches.append(new_match, ignore_index=True)
matches = matches.drop_duplicates()
full_matches = combinations_sorted.merge(matches,
on=["uri_1", "uri_2"],
how="outer")
full_matches["value"] = np.where(full_matches["value"].isna(), 0,
full_matches["value"])
return full_matches
def qualified_relation_generator(df,
columns,
endpoint=DBpedia,
uri_data_model=False,
progress=True,
prefix="Link",
direction="Out",
properties_regex_filter=None,
types_regex_filter=None,
result_type="boolean",
hierarchy=False,
prefix_lookup=False,
caching=True):
"""Qualified relation generator considers not only relations, but also the
related types, adding boolean, counts, relative counts or tfidf-values
features for incoming and outgoing relations.
Args:
df (pd.DataFrame): Dataframe to which links are added.
columns (str/list): Name(s) of column(s) which contain(s) the link(s)
to the knowledge graph.
endpoint (Endpoint, optional): SPARQL Endpoint to be queried; ignored
when "uri_data_model" = True. Defaults to DBpedia.
uri_data_model (bool, optional): If enabled, the URI is directly
queried instead of a SPARQL endpoint. Defaults to False.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process. Defaults to
True.
prefix (str, optional): Custom prefix for the SPARQL query. Defauls to
"Link".
direction (str, optional): The direction for properties which choose
from Incoming, Outgoing (In and Out). Defaults to "Out".
properties_regex_filter (str, optional): Regular expression for
filtering properties. Defaults to None.
types_regex_filter (str, optional): Regular expression for filtering
types. Defaults to None.
result_type (str, optional): States wether the results should be
boolean ("boolean"), counts ("counts"), relative counts
("relative") or tfidf-values ("tfidf") Defaults to "boolean".
hierarchy (bool, optional): If True, a hierarchy of all superclasses of
the returned types is attached to the resulting dataframe. Defaults
to False.
prefix_lookup (bool/str/dict, optional):
True: Namespaces of prefixes will be looked up at
prefix.cc and added to the sparql query.
str: User provides the path to a json-file with
prefixes and namespaces.
dict: User provides a dictionary with prefixes and
namespaces.
Defaults to False.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: Dataframe with new columns containing the links of properties to the knowledge graph
"""
df = df.copy()
if hierarchy:
hierarchyGraph = nx.DiGraph()
#convert columns to list to enable iteration
if not isinstance(columns, list):
columns = [columns]
#iterate over possibly several link columns
if progress:
iterator = tqdm(columns, desc="Column")
else:
iterator = columns
for col in iterator:
if not uri_data_model:
values = " ( <" + df[col].str.cat(sep="> ) ( <") + "> ) "
if direction == "Out":
query = "SELECT ?value ?p ?o ?type WHERE {VALUES (?value) {" + values + "} ?value ?p ?o. ?o rdf:type ?type. "
elif direction == "In":
query = "SELECT ?value ?p ?s ?type WHERE {VALUES (?value) {" + values + "} ?s ?p ?value. ?s rdf:type ?type. "
if properties_regex_filter != None:
regex_string = regex_string_generator("?p",
properties_regex_filter)
query = query + "FILTER(" + regex_string + ") "
if types_regex_filter != None:
regex_string = regex_string_generator("?type",
types_regex_filter)
query = query + "FILTER(" + regex_string + ") "
query = query + "}"
result_df = endpoint_wrapper(
query, endpoint, prefix_lookup=prefix_lookup,
caching=caching).drop_duplicates().reset_index(drop=True)
else:
if direction == "Out":
query = "SELECT ?value ?p ?o ?type WHERE {VALUES (?value) {(<**URI**>)} ?value ?p ?o. ?o rdf:type ?type. "
elif direction == "In":
query = "SELECT ?value ?p ?s ?type WHERE {VALUES (?value) {(<**URI**>)} ?s ?p ?value. ?s rdf:type ?type. "
if properties_regex_filter != None:
regex_string = regex_string_generator("str(?p)",
properties_regex_filter)
query = query + "FILTER(" + regex_string + ") "
if types_regex_filter != None:
regex_string = regex_string_generator("str(?type)",
types_regex_filter)
query = query + "FILTER(" + regex_string + ") "
query = query + "}"
result_df = uri_querier(df,
col,
query,
prefix_lookup=prefix_lookup,
progress=progress,
caching=caching)
if type(result_df) != type(pd.DataFrame()):
pass
if result_df.empty:
pass
else:
if hierarchy:
hierarchy_col = hierarchy_graph_generator(
result_df["type"],
hierarchy_relation=
"http://www.w3.org/2000/01/rdf-schema#subClassOf",
max_hierarchy_depth=None,
endpoint=endpoint,
uri_data_model=uri_data_model,
progress=progress,
caching=caching)
hierarchyGraph = nx.compose(hierarchyGraph, hierarchy_col)
result_df[
"link_with_type"] = result_df["p"] + "_type_" + result_df["type"]
result_df = result_df[["value", "link_with_type"]]
result_df_dummies = result_df.join(
result_df["link_with_type"].str.get_dummies()).drop(
"link_with_type", axis=1)
result_df = get_result_df(
result_df_dummies, result_type,
prefix + "_" + direction + "_" + result_type + "_", df, columns)
if hierarchy:
# append hierarchy to df as attribute, this will generate a warning but works
result_df.attrs = {"hierarchy": hierarchyGraph}
return result_df
def specific_relation_generator(
df,
columns,
endpoint=DBpedia,
uri_data_model=False,
progress=True,
direct_relation="http://purl.org/dc/terms/subject",
hierarchy_relation=None,
max_hierarchy_depth=1,
prefix_lookup=False,
caching=True):
"""Creates attributes from a specific direct relation. Additionally, it is
possible to append a hierarchy with a user-defined hierarchy relation.
Args:
df (pd.DataFrame): the dataframe to extend
columns (str/list): Name(s) of column(s) which contain(s) the link(s)
to the knowledge graph.
endpoint (Endpoint, optional): SPARQL Endpoint to be queried; ignored
when "uri_data_model" = True. Defaults to DBpedia.
uri_data_model (bool, optional): If enabled, the URI is directly queried
instead of a SPARQL endpoint. Defaults to False.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process. Defaults
to True.
direct_relation (str, optional): Direct relation used to create
features. Defaults to "http://purl.org/dc/terms/subject".
hierarchy_relation (str, optional): Hierarchy relation used to connect
categories, e.g. http://www.w3.org/2004/02/skos/core#broader.
Defaults to None.
max_hierarchy_depth (int, optional): Maximal number of hierarchy steps
taken. Defaults to 1.
prefix_lookup (bool/str/dict, optional):
True: Namespaces of prefixes will be looked up at
prefix.cc and added to the sparql query.
str: User provides the path to a json-file with
prefixes and namespaces.
dict: User provides a dictionary with prefixes and
namespaces.
Defaults to False.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: The dataframe with additional features.
"""
df = df.copy()
if hierarchy_relation:
hierarchy_relation = re.sub(r"^.*?https://", "http://",
hierarchy_relation)
hierarchy = nx.DiGraph()
direct_relation = re.sub(r"^.*?https://", "http://", direct_relation)
# convert columns to list to enable iteration
if not isinstance(columns, list):
columns = [columns]
if df[columns].isna().all().item():
return df
# iterate over possibly several link columns
if progress:
iterator = tqdm(columns, desc="Column")
else:
iterator = columns
for col in iterator:
if not uri_data_model:
# Create Sparql Query
values = "(<" + df[col].str.cat(sep=">) (<") + ">) "
query = "SELECT ?value ?object "
query += " WHERE {VALUES (?value) {" + values
query += "} ?value (<" + direct_relation + ">) ?object. }"
# Retrieve query results from endpoint
query_result = endpoint_wrapper(
query, endpoint, prefix_lookup=prefix_lookup, caching=caching).\
drop_duplicates().reset_index(drop=True)
else:
# Create URI Query
query = "SELECT ?value ?object WHERE {VALUES (?value) {(<**URI**>)}"
query += " ?value (<" + direct_relation + ">) ?object. }"
query_result = uri_querier(df,
col,
query,
prefix_lookup=prefix_lookup,
progress=progress,
caching=caching)
# delete empty columns (for example when hierarchy relation returns
# nothing)
query_result = query_result.dropna(how="all", axis=1)
# check if there are valid results, if not return the original frame
if query_result.empty:
continue
# extract hierarchy
if hierarchy_relation:
hierarchy_col = hierarchy_graph_generator(
query_result["object"],
hierarchy_relation=hierarchy_relation,
max_hierarchy_depth=max_hierarchy_depth,
endpoint=endpoint,
uri_data_model=uri_data_model,
progress=progress,
caching=caching)
hierarchy = nx.compose(hierarchy, hierarchy_col)
query_grouped = query_result.groupby("value")["object"].apply(list)
# bundle the unique new features
new_cols = pd.Series(query_grouped.values.sum()).unique()
# create shape of result dataframe to fill
df_to_append = pd.DataFrame(columns=new_cols)
df_to_append["value"] = query_grouped.index
# check for each URI if it belongs to the category and tick True/False
for row, new_col in itertools.product(df_to_append.index, new_cols):
df_to_append.loc[row, new_col] = np.where(
new_col in query_grouped[df_to_append.loc[row, "value"]], True,
False).item()
# merge the new column with the original dataframe
df_to_append.rename({"value": col}, axis=1, inplace=True)
df = pd.merge(df, df_to_append, how="left", on=col)
# rename columns
if new_cols.any():
df.columns = [
col + "_in_boolean_" + name if name in new_cols else name
for name in df.columns
]
# append hierarchy to df as attribute, this will generate a warning but
# works
if hierarchy_relation:
df.attrs = {"hierarchy": hierarchy}
return df
def unqualified_relation_generator(df,
columns,
endpoint=DBpedia,
uri_data_model=False,
progress=True,
prefix="Link",
direction="Out",
regex_filter=None,
result_type="boolean",
prefix_lookup=False,
caching=True):
"""Unqualified relation generator creates attributes from the existence of
relations and adds boolean, counts, relative counts or tfidf-values features
for incoming and outgoing relations.
Args:
df (pd.DataFrame): Dataframe to which links are added.
columns (str/list): Name(s) of column(s) which contain(s) the link(s)
to the knowledge graph.
endpoint (Endpoint, optional): SPARQL Endpoint to be queried; ignored
when "uri_data_model" = True. Defaults to DBpedia.
uri_data_model (bool, optional): If enabled, the URI is directly
queried instead of a SPARQL endpoint. Defaults to False.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process. Defaults to
True.
prefix (str, optional): Custom prefix for the SPARQL query. Defauls to
"Link".
direction (str, optional): The direction for properties which choose
from Incoming, Outgoing (In and Out). Defaults to "Out".
regex_filter (str, optional): Regular expression for filtering
properties. Defaults to None.
result_type (str, optional): States wether the results should be
boolean ("boolean"), counts ("counts"), relative counts
("relative") or tfidf-values ("tfidf") Defaults to "boolean".
prefix_lookup (bool/str/dict, optional):
True: Namespaces of prefixes will be looked up at
prefix.cc and added to the sparql query.
str: User provides the path to a json-file with
prefixes and namespaces.
dict: User provides a dictionary with prefixes and
namespaces.
Defaults to False.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: Dataframe with new columns containing the links of
properties to the knowledge graph
"""
df = df.copy()
#convert columns to list to enable iteration
if not isinstance(columns, list):
columns = [columns]
#iterate over possibly several link columns
if progress:
iterator = tqdm(columns, desc="Column")
else:
iterator = columns
for col in iterator:
if not uri_data_model:
values = " ( <" + df[col].str.cat(sep="> ) ( <") + "> ) "
if direction == "Out":
query = "SELECT DISTINCT ?value ?p ?o WHERE {VALUES (?value) {" + values + "} ?value ?p ?o "
elif direction == "In":
query = "SELECT DISTINCT ?value ?p ?s WHERE {VALUES (?value) {" + values + "} ?s ?p ?value "
if regex_filter != None:
regex_string = regex_string_generator("?p", regex_filter)
query = query + "FILTER(" + regex_string + ") "
query = query + "}"
result_df = endpoint_wrapper(
query, endpoint, prefix_lookup=prefix_lookup,
caching=caching).drop_duplicates().reset_index(drop=True)
else:
if direction == "Out":
query = "SELECT DISTINCT ?value ?p ?o WHERE {VALUES (?value) { (<**URI**>)} ?value ?p ?o "
elif direction == "In":
query = "SELECT DISTINCT ?value ?p ?s WHERE {VALUES (?value) { (<**URI**>)} ?s ?p ?value "
if regex_filter != None:
regex_string = regex_string_generator("str(?p)", regex_filter)
query = query + "FILTER(" + regex_string + ") "
query = query + "}"
result_df = uri_querier(df,
col,
query,
prefix_lookup=prefix_lookup,
progress=progress,
caching=caching)
if type(result_df) != type(pd.DataFrame()):
pass
if result_df.empty:
pass
else:
result_df_dummies = result_df.join(
result_df["p"].str.get_dummies()).drop("p", axis=1)
result_df = get_result_df(
result_df_dummies, result_type,
prefix + "_" + direction + "_" + result_type + "_", df, columns)
return result_df
def direct_type_generator(df,
columns,
endpoint=DBpedia,
uri_data_model=False,
progress=True,
prefix="",
regex_filter=None,
result_type="boolean",
bundled_mode=True,
hierarchy=False,
prefix_lookup=False,
caching=True):
"""Generator that takes a dataset with (a) link(s) to a knowledge graph and
queries the type(s) of the linked ressources (using rdf:type). The
resulting types are added as new columns, which are filled either with a
boolean indicator or a count.
Args:
df (pd.DataFrame): Dataframe to which types are added.
columns (str/list): Name(s) of column(s) which contain(s) the link(s)
to the knowledge graph.
endpoint (Endpoint, optional): SPARQL Endpoint to be queried; ignored
when "uri_data_model" = True. Defaults to DBpedia.
uri_data_model (bool, optional): If enabled, the URI is directly
queried instead of a SPARQL . Defaults to False.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process . Defaults
to True.
prefix (str, optional): Custom prefix for the SPARQL query. Defaults to
"".
regex_filter (list, optional): A list filled with regexes (as strings)
to filter the results . Defaults to None.
result_type (str, optional): States wether the results should be
boolean ("boolean"), counts ("counts"), relative counts
("relative") or tfidf-values ("tfidf") . Defaults to "boolean".
bundled_mode (bool, optional): If True, all necessary queries are
bundled into one query (using the VALUES method). - Requires a
SPARQL 1.1 implementation! . Defaults to True.
hierarchy (bool, optional): If True, a hierarchy of all superclasses of
the returned types is attached to the resulting dataframe. Defaults
to False.
prefix_lookup (bool/str/dict, optional):
True: Namespaces of prefixes will be looked up at
prefix.cc and added to the sparql query.
str: User provides the path to a json-file with
prefixes and namespaces.
dict: User provides a dictionary with prefixes and
namespaces.
Defaults to False.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: Returns dataframe with (a) new column(s) containing the
found types.
"""
df = df.copy()
final_result_df = pd.DataFrame()
if hierarchy:
hierarchyGraph = nx.DiGraph()
# convert columns to list to enable iteration
if not isinstance(columns, list):
columns = [columns]
# Create SPARQL query (based on rdf:type) for each user-specified column
if progress:
iterator = tqdm(columns, desc="Column")
else:
iterator = columns
for column in iterator:
# If bundled_mode is selected all necessary queries for a column are bundled into one query (using the VALUES method). -> Way faster But less compatible.
if bundled_mode and not uri_data_model:
values = " ( <" + df[column].str.cat(sep="> ) ( <") + "> ) "
query = prefix + \
" SELECT DISTINCT ?value ?types WHERE {VALUES (?value) {" + \
values+"} ?value rdf:type ?types . "
if regex_filter != None:
regex_string = regex_string_generator("?types", regex_filter)
query = query + "FILTER(" + regex_string + ") "
query = query + "}"
result_df = endpoint_wrapper(
query, endpoint, prefix_lookup=prefix_lookup,
caching=caching).drop_duplicates().reset_index(drop=True)
else:
result_df = pd.DataFrame()
if uri_data_model:
query = prefix + \
" SELECT DISTINCT ?value ?types WHERE {VALUES (?value) {(<**URI**>)} ?value rdf:type ?types . "
if regex_filter != None:
regex_string = regex_string_generator(
"str(?types)", regex_filter)
query = query + "FILTER(" + regex_string + ") "
query = query + "}"
result_df = uri_querier(df,
column,
query,
prefix_lookup=prefix_lookup,
progress=progress,
caching=caching)
else:
for uri in df[column].iteritems():
if pd.notna(uri[1]):
query = prefix + \
" SELECT DISTINCT ?value ?types WHERE {?value rdf:type ?types . FILTER (?value = <" + \
uri[1]+">"
if regex_filter != None:
query = query + " && (" + regex_string_generator(
"?types", regex_filter) + ")"
query = query + ") }"
result = endpoint_wrapper(query,
endpoint,
prefix_lookup=prefix_lookup,
caching=caching)
result_df = result_df.append(result)
else:
pass
result_df = result_df.rename(
{
"callret-0": "value"
}, axis="columns").drop_duplicates().reset_index(drop=True)
if hierarchy:
hierarchy_col = hierarchy_graph_generator(
result_df["types"],
hierarchy_relation=
"http://www.w3.org/2000/01/rdf-schema#subClassOf",
max_hierarchy_depth=None,
endpoint=endpoint,
uri_data_model=uri_data_model,
progress=progress,
caching=caching)
hierarchyGraph = nx.compose(hierarchyGraph, hierarchy_col)
if result_df.empty:
result_columns = []
pass
else:
# Results are transformed to a sparse dataframe (rows: looked-up uris; columns: types) with dummy-encoding (0/1) -> Each result is one row
result_df_dummies = result_df.join(
result_df.types.str.get_dummies()).drop("types", axis=1)
# Sparse dataframe is grouped by uri
result_df_grouped = result_df_dummies.groupby("value").sum()
# Result columns get prefix (format depends on single or multiple columns)
if len(columns) > 1:
result_df_grouped = result_df_grouped.add_prefix("type_")
else:
result_df_grouped = result_df_grouped.add_prefix(column +
"_type_")
# Results get concatenated to the queried columns (to be used as identifiers) (??)
result_df_merged = pd.merge(df[columns],
result_df_grouped,
left_on=column,
right_on="value",
how="outer").drop_duplicates()
# If multiple columns with URIs are looked up: Current results are merged with the results of previous passes of the loop
final_result_df = pd.concat([final_result_df, result_df_merged],
sort=False).groupby(
columns,
dropna=False).sum().reset_index()
# Result columns are determined and converted to the correct dtype
result_columns = list(
set(list(final_result_df.columns)) - set(columns))
final_result_df[result_columns] = final_result_df[
result_columns].astype("int64")
if not final_result_df.empty:
# If result_type is boolean, all values greater 0 are changed to True all others to False
if result_type == "boolean":
final_result_df[result_columns] = final_result_df[
result_columns].astype("bool")
# If result_type is "relative" or "tfidf", calculate the relative counts per row
elif result_type in ["relative", "tfidf"]:
# Calculate the relative counts by dividing each row by its sum, fillna(0) to replace missings created by division by zero (when sum=0)
final_result_df_relative = final_result_df.copy()
final_result_df_relative[result_columns] = final_result_df[
result_columns].div(
final_result_df[result_columns].sum(axis=1),
axis=0).fillna(0)
# If result_type is "tfidf", use the table of relative counts to create the table of tfidf-values
if result_type == "tfidf":
# Calculate idf values
N = len(final_result_df[result_columns])
nt = final_result_df[result_columns][
final_result_df[result_columns] >= 1].count(axis=0)
idf = np.log(N / nt).replace(np.inf, 0)
# Multiply relative counts with idf values
final_result_df_relative[
result_columns] = final_result_df_relative[
result_columns].multiply(idf, axis="columns")
final_result_df = final_result_df_relative.copy()
# Collected query-results get appended to the original dataframe
df = pd.merge(df, final_result_df, on=columns, how="outer")
if hierarchy:
df.attrs = {"hierarchy": hierarchyGraph}
return df
def data_properties_generator(df,
columns,
endpoint=DBpedia,
uri_data_model=False,
progress=True,
type_filter=None,
regex_filter=None,
bundled_mode=True,
prefix_lookup=False,
caching=True):
"""Generator that takes a dataset with a link to a knowledge graph and
creates a new feature for each data property of the given resource.
Args:
df (pd.DataFrame): Dataframe to which the features will be added
columns (str/list): Name(s) of column(s) which contain(s) the link(s)
to the knowledge graph.
endpoint (Endpoint, optional): Base string to the knowledge graph;
ignored when "uri_data_model" = True. Defaults to DBpedia.
uri_data_model (bool, optional): If enabled, the URI is directly
queried instead of a SPARQL endpoint. Defaults to False.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process. Defaults to
True.
type_filter (str, optional): Property datatype to be selected from
results (e.g. xsd:string). If a specific datatype should be
excluded a "- " needs to be prepended (e.g. - xsd:string). Defaults
to None.
regex_filter (str, optional): Regular expression for filtering
properties. Defaults to None.
bundled_mode (bool, optional): If True, all necessary queries are
bundled into one query (using the VALUES method). - Requires a
SPARQL 1.1 implementation! . Defaults to True.
prefix_lookup (bool/str/dict, optional):
True: Namespaces of prefixes will be looked up at
prefix.cc and added to the sparql query.
str: User provides the path to a json-file with
prefixes and namespaces.
dict: User provides a dictionary with prefixes and
namespaces.
Defaults to False.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: Dataframe with a new column for each property.
"""
df = df.copy()
# convert columns to list to enable iteration
if not isinstance(columns, list):
columns = [columns]
# Prepare Type Filter Statement (Decode Include/Exclude)
if type_filter != None:
if type_filter[0:2] == "- ":
type_filter_str = " && DATATYPE(?v) != " + type_filter[2:]
else:
type_filter_str = " && DATATYPE(?v) = " + type_filter
# Create SPARQL query for each user-specified column
if progress:
iterator = tqdm(columns, desc="Column")
else:
iterator = columns
for col in iterator:
if bundled_mode and not uri_data_model:
values = " ( <" + df[col].str.cat(sep="> ) ( <") + "> ) "
query = "SELECT ?value ?p ?v WHERE {VALUES (?value) {" + \
values + "} ?value ?p ?v FILTER(isLITERAL(?v)"
if type_filter != None:
query = query + type_filter_str
if regex_filter != None:
query = query + " && regex(?p, \"" + regex_filter + "\")"
query = query + ")}"
result_df = endpoint_wrapper(
query, endpoint, prefix_lookup=prefix_lookup,
caching=caching).drop_duplicates().reset_index(drop=True)
else:
result_df = pd.DataFrame()
if uri_data_model:
query = "SELECT DISTINCT ?value ?p ?v WHERE {VALUES (?value) {(<**URI**>)} ?value ?p ?v FILTER(isLITERAL(?v)"
if type_filter != None:
query = query + type_filter_str
if regex_filter != None:
query = query + " && regex(?p, \"" + regex_filter + "\")"
query = query + ")}"
result_df = uri_querier(df,
col,
query,
prefix_lookup=prefix_lookup,
progress=progress,
caching=caching)
else:
for uri in df[col].iteritems():
if pd.notna(uri[1]):
query = "SELECT DISTINCT ?value ?p ?v WHERE {?value ?p ?v . FILTER (?value = <" + \
uri[1]+"> && (isLITERAL(?v))"
if type_filter != None:
query = query + type_filter_str
if regex_filter != None:
query = query + " && regex(?p, \"" + regex_filter + "\")"
query = query + ")} "
result = endpoint_wrapper(query,
endpoint,
prefix_lookup=prefix_lookup,
caching=caching)
result_df = result_df.append(result)
else:
pass
if result_df.empty:
pass
else:
# Results are transformed to a sparse dataframe (rows: looked-up uris; columns: types) with dummy-encoding (0/1) -> Each result is on row
result_df["p"] = col + "_data_" + result_df["p"]
# transform values into new columns
result_df = result_df.pivot_table(values="v",
index="value",
columns="p",
aggfunc=np.random.choice)
# append properties to dataframe
df = pd.merge(df,
result_df,
how="left",
left_on=col,
right_on="value")
return df
def check_uri_redirects(
df,
column,
replace=True,
custom_name_postfix=None,
redirection_property="http://dbpedia.org/ontology/wikiPageRedirects",
endpoint=DBpedia,
regex_filter="dbpedia",
bundled_mode=True,
uri_data_model=False,
progress=True,
caching=True):
"""Takes a column of URIs from a DataFrame and checks for each if it has a
redirection set by the endpoint. If this is the case, the URI it redirects
to is either added in a new column or replaces the original URI.
Args:
df (pd.DataFrame): Dataframe for which the URIs should be inspected.
column (str): Name of the column that contains the URIs that should be
checked.
replace (bool, optional): If True: URIs that get redirected will be
replaced with the new URI; If False: A new column, containing the
result for each URI, is added to the DataFrame. Defaults to True.
custom_name_postfix (str, optional): Custom postfix for the newly
created column (in case "replace" is set to False). Defaults to None.
redirection_property (str, optional): Relation/Property URI that
signals a redirect for this endpoint. Defaults to
"http://dbpedia.org/ontology/wikiPageRedirects".
endpoint (Endpoint, optional): SPARQL Endpoint to be queried; ignored
when "uri_data_model" = True. Defaults to DBpedia.
regex_filter (str, optional): Just URIs matching the specified RegEx
are checked for redirects. Defaults to "dbpedia".
bundled_mode (bool, optional): If True, all necessary queries are
bundled into one query (using the VALUES method). - Requires a
SPARQL 1.1 implementation!; ignored when "uri_data_model" = True.
Defaults to True.
uri_data_model (bool, optional): If enabled, the URI is directly
queried instead of a SPARQL endpoint. Defaults to False.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process (if
"uri_data_model" = True). Defaults to True.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Raises:
ValueError: Raised if 'custom_name_postfix' is set to "" instead of
None.
Returns:
pd.DataFrame: Returns dataframe with cleaned links / a new column.
"""
if custom_name_postfix == "":
raise ValueError(
"'custom_name_postfix' can't be an empty string. If you don't want to use a custom_name_postfix, please set the attribute to None"
)
df = df.copy()
if bundled_mode and not uri_data_model:
values = " ( <" + df[column].str.cat(sep="> ) ( <") + "> ) "
query = "SELECT DISTINCT ?value ?redirect WHERE {VALUES (?value) {" + values + "} ?value <" + redirection_property + "> ?redirect . }"
result_df = endpoint_wrapper(
query, endpoint,
caching=caching).drop_duplicates().reset_index(drop=True)
else:
result_df = pd.DataFrame()
if uri_data_model:
query = "SELECT DISTINCT ?value ?redirect WHERE {VALUES (?value) {(<**URI**>)} ?value <" + redirection_property + "> ?redirect . }"
result_df = uri_querier(df,
column,
query,
regex_filter=regex_filter,
progress=progress,
caching=caching)
else:
for uri in df[column].iteritems():
if pd.notna(uri[1]):
query = "SELECT DISTINCT ?value ?redirect WHERE {?value <" + redirection_property + "> ?redirect . FILTER (?value = <" + uri[
1] + ">) }"
result = endpoint_wrapper(query, endpoint, caching=caching)
result_df = result_df.append(result)
else:
pass
result_df = result_df.rename({
"callret-0": "value"
}, axis="columns").drop_duplicates().reset_index(drop=True)
if result_df.empty:
return df
else:
if custom_name_postfix == None:
new_attribute_name = column + "_redirect"
else:
new_attribute_name = column + custom_name_postfix
result_df = pd.merge(df,
result_df,
how="left",
left_on=column,
right_on="value").drop("value", axis=1).rename(
columns={"redirect": new_attribute_name})
if replace:
result_df.loc[(pd.isnull(result_df[new_attribute_name])),
new_attribute_name] = result_df[column]
result_df.drop(column, axis=1, inplace=True)
result_df.rename(columns={new_attribute_name: column},
inplace=True)
return result_df
def link_explorer(df, base_link_column, number_of_hops = 1, links_to_follow = ["owl:sameAs"], lod_sources = [], exclude_sources = [], prefix_lookup=False, progress = True, caching=True):
"""Follows the defined links starting from a base link to a certain number
of hops. Adds the discovered links as new columns to the dataframe.
Args:
df (pd.DataFrame): Dataframe with a base link
base_link_column (str): Name of column which contains the base link to
start with.
number_of_hops (int, optional): Depth of exlporation of the LOD cloud.
Defaults to 1.
links_to_follow (list, optional): Names of links that should be
followed. Defaults to "owl:sameAs".
lod_sources (list, optional): Restrict exploration to certain datasets.
Use strings or regular expressions to define the allowed datasets.
Defaults to [].
exclude_sources (list, optional): Exclude certain datasets from
exploration. Use strings or regular expressions to define the
datasets. Defaults to [].
prefix_lookup (bool/str/dict, optional):
True: Namespaces of prefixes will be looked up at
prefix.cc and added to the sparql query.
str: User provides the path to a json-file with
prefixes and namespaces.
dict: User provides a dictionary with prefixes and
namespaces.
Defaults to False.
progress (bool, optional): If True, progress bars will be shown to
inform the user about the progress made by the process. Defaults to
True.
caching (bool, optional): Turn result-caching for queries issued during
the execution on or off. Defaults to True.
Returns:
pd.DataFrame: Dataframe with a new column for each discovered link.
"""
if not isinstance(links_to_follow, list):
links_to_follow = [links_to_follow]
if not isinstance(exclude_sources, list):
exclude_sources = [exclude_sources]
if not isinstance(lod_sources, list):
lod_sources = [lod_sources]
all_links = list(df[base_link_column])
query_raw = " SELECT DISTINCT ?value ?uri{} WHERE {{VALUES (?value) {{(<**URI**>)}} ?value " + "|".join(links_to_follow) + " ?uri{} }} "
df_merged = pd.DataFrame()
df_all = pd.DataFrame()
if progress:
iterator = tqdm(
range(1,number_of_hops+1), desc="Link Explorer - Performing Hops.")
else:
iterator = range(1,number_of_hops+1)
for hop in iterator:
query = query_raw.format(str(hop),str(hop))
if hop == 1:
df_result = uri_querier(df, base_link_column, query, prefix_lookup=prefix_lookup, caching=caching, progress=progress)
else:
df_result = uri_querier(df_result, "uri"+str(hop-1), query, prefix_lookup=prefix_lookup, caching=caching, progress=progress)
if df_result.empty:
break
# eliminate duplicate links
df_result = df_result[~df_result["uri"+str(hop)].isin(all_links)]
# filter sources
if lod_sources:
df_result = df_result[df_result["uri"+str(hop)].str.contains("|".join(lod_sources))]
# exclude certain sources defined by string or regex
if exclude_sources:
df_result = df_result[~df_result["uri"+str(hop)].str.contains("|".join(exclude_sources))]
if df_result.empty:
break
if df_merged.empty:
df_merged = df_result
else:
df_merged = pd.merge(df_merged, df_result, left_on="uri"+str(hop-1), right_on="value", how="left", suffixes=("", "_y")).drop("value_y",axis=1)
df_all = df_all.append(df_merged[["value","uri"+str(hop)]].rename(columns={"uri"+str(hop) : "uri"}))
df_all = df_all.dropna().drop_duplicates()
all_links += df_result["uri"+str(hop)].tolist()
if df_all.empty:
return df
df_all["count"] = np.nan
regex_pattern = "^http:/"
while True:
regex_pattern += "/[^/]*"
df_all["pld"] = df_all.apply(
lambda x: x["pld"] if x["count"] == 1 else re.search(r"{}".format(regex_pattern), x["uri"]).group(), axis=1)
df_all = df_all.drop("count", axis=1)
df_with_counts = df_all.groupby(["value","pld"]).size().reset_index(name="count")
df_all = pd.merge(df_all, df_with_counts, left_on=["value","pld"], right_on=["value","pld"])
#break loop when all counts are 1
if (df_all["count"] == 1).all():
break
df_pivot = df_all.pivot_table(values="uri", index="value", columns="pld", aggfunc="first").reset_index()
df_final = pd.merge(df, df_pivot, left_on=base_link_column, right_on="value", how="outer").drop("value",axis=1)
return df_final
