Split pandas functions into separate module.

This frees //labm8:sqlutil from the dependency on
//third_party/py/pandas, which is currently broken.

github.com/ChrisCummins/phd/issues/51

[Exported from 2391f3a74286a844b98a5537a0e17c4a19ddf324]

labm8/BUILD

@@ -547,6 +547,28 @@ py_test(
     ],
 )
 
+py_library(
+    name = "pdutil",
+    srcs = ["pdutil.py"],
+    visibility = ["//visibility:public"],
+    deps = [
+        ":app",
+        ":sqlutil",
+        "//third_party/py/pandas",
+    ],
+)
+
+py_test(
+    name = "pdutil_test",
+    srcs = ["pdutil_test.py"],
+    deps = [
+        ":pdutil",
+        ":sqlutil",
+        ":test",
+        "//third_party/py/sqlalchemy",
+    ],
+)
+
 py_library(
     name = "ppar",
     srcs = ["ppar.py"],
@@ -627,7 +649,6 @@ py_library(
         ":pbutil",
         ":text",
         "//third_party/py/absl",
-        "//third_party/py/pandas",
         "//third_party/py/sqlalchemy",
     ],
 )

labm8/pdutil.py

@@ -0,0 +1,61 @@
+# Copyright 2014-2019 Chris Cummins <[email protected]>.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Utility code for working with pandas."""
+import pandas as pd
+import typing
+from absl import flags as absl_flags
+
+from labm8 import sqlutil
+
+FLAGS = absl_flags.FLAGS
+
+
+def QueryToDataFrame(session: sqlutil.Session,
+                     query: sqlutil.Query) -> pd.DataFrame:
+  """Read query results to a Pandas DataFrame.
+
+  Args:
+    session: A database session.
+    query: The query to run.
+
+  Returns:
+    A Pandas DataFrame.
+  """
+  return pd.read_sql(query.statement, session.bind)
+
+
+def ModelToDataFrame(
+    session: sqlutil.Session,
+    model,
+    columns: typing.Optional[typing.List[str]] = None,
+    query_identity=lambda q: q,
+):
+  """Construct and execute a query reads an object's fields to a dataframe.
+
+  Args:
+    session: A database session.
+    model: A database mapped object.
+    columns: A list of column names, where each element is a column mapped to
+      the model. If not provided, all column names are used.
+    query_identity: A function which takes the produced query and returns a
+      query. Use this to implement filtering of the query results.
+
+  Returns:
+    A Pandas DataFrame with one column for each field.
+  """
+  columns = columns or ColumnNames(model)
+  query = session.query(*[getattr(model, column) for column in columns])
+  df = QueryToDataFrame(session, query_identity(query))
+  df.columns = columns
+  return df

labm8/pdutil_test.py

@@ -0,0 +1,67 @@
+# Copyright 2014-2019 Chris Cummins <[email protected]>.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Unit tests for //labm8:sqlutil."""
+import sqlalchemy as sql
+from sqlalchemy.ext import declarative
+
+from labm8 import pdutil
+from labm8 import sqlutil
+
+
+def test_QueryToDataFrame_column_names():
+  """Test that expected column names are set."""
+  base = declarative.declarative_base()
+
+  class Table(base):
+    __tablename__ = 'test'
+    col_a = sql.Column(sql.Integer, primary_key=True)
+    col_b = sql.Column(sql.Integer)
+
+  db = sqlutil.Database('sqlite://', base)
+  with db.Session() as s:
+    df = pdutil.QueryToDataFrame(s, s.query(Table.col_a, Table.col_b))
+
+  assert list(df.columns.values) == ['col_a', 'col_b']
+
+
+def test_ModelToDataFrame_column_names():
+  """Test that expected column names are set."""
+  base = declarative.declarative_base()
+
+  class Table(base):
+    __tablename__ = 'test'
+    col_a = sql.Column(sql.Integer, primary_key=True)
+    col_b = sql.Column(sql.Integer)
+
+  db = sqlutil.Database('sqlite://', base)
+  with db.Session() as s:
+    df = pdutil.ModelToDataFrame(s, Table)
+
+  assert list(df.columns.values) == ['col_a', 'col_b']
+
+
+def test_QueryToDataFrame_explicit_column_names():
+  """Test that expected column names are set."""
+  base = declarative.declarative_base()
+
+  class Table(base):
+    __tablename__ = 'test'
+    col_a = sql.Column(sql.Integer, primary_key=True)
+    col_b = sql.Column(sql.Integer)
+
+  db = sqlutil.Database('sqlite://', base)
+  with db.Session() as s:
+    df = pdutil.ModelToDataFrame(s, Table, ['col_b'])
+
+  assert list(df.columns.values) == ['col_b']

labm8/sqlutil.py

@@ -12,14 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """Utility code for working with sqlalchemy."""
+import time
+
 import collections
 import contextlib
 import pathlib
-import time
-import typing
-
-import pandas as pd
 import sqlalchemy as sql
+import typing
 from absl import flags as absl_flags
 from sqlalchemy import func
 from sqlalchemy import orm
@@ -468,45 +467,6 @@ def __repr__(self) -> str:
     return self.url
 
 
-def QueryToDataFrame(session: Session, query: Query) -> pd.DataFrame:
-  """Read query results to a Pandas DataFrame.
-
-  Args:
-    session: A database session.
-    query: The query to run.
-
-  Returns:
-    A Pandas DataFrame.
-  """
-  return pd.read_sql(query.statement, session.bind)
-
-
-def ModelToDataFrame(
-    session: Session,
-    model,
-    columns: typing.Optional[typing.List[str]] = None,
-    query_identity=lambda q: q,
-):
-  """Construct and execute a query reads an object's fields to a dataframe.
-
-  Args:
-    session: A database session.
-    model: A database mapped object.
-    columns: A list of column names, where each element is a column mapped to
-      the model. If not provided, all column names are used.
-    query_identity: A function which takes the produced query and returns a
-      query. Use this to implement filtering of the query results.
-
-  Returns:
-    A Pandas DataFrame with one column for each field.
-  """
-  columns = columns or ColumnNames(model)
-  query = session.query(*[getattr(model, column) for column in columns])
-  df = QueryToDataFrame(session, query_identity(query))
-  df.columns = columns
-  return df
-
-
 class TablenameFromClassNameMixin(object):
   """A class mixin which derives __tablename__ from the class name.
 

labm8/sqlutil_test.py

@@ -13,10 +13,9 @@
 # limitations under the License.
 """Unit tests for //labm8:sqlutil."""
 import pathlib
-import typing
-
 import pytest
 import sqlalchemy as sql
+import typing
 from sqlalchemy.ext import declarative
 
 from labm8 import sqlutil
@@ -114,54 +113,6 @@ class Table(base, sqlutil.TablenameFromClassNameMixin):
   assert sqlutil.ColumnNames(instance) == ['col_a', 'col_b']
 
 
-def test_QueryToDataFrame_column_names():
-  """Test that expected column names are set."""
-  base = declarative.declarative_base()
-
-  class Table(base):
-    __tablename__ = 'test'
-    col_a = sql.Column(sql.Integer, primary_key=True)
-    col_b = sql.Column(sql.Integer)
-
-  db = sqlutil.Database('sqlite://', base)
-  with db.Session() as s:
-    df = sqlutil.QueryToDataFrame(s, s.query(Table.col_a, Table.col_b))
-
-  assert list(df.columns.values) == ['col_a', 'col_b']
-
-
-def test_ModelToDataFrame_column_names():
-  """Test that expected column names are set."""
-  base = declarative.declarative_base()
-
-  class Table(base):
-    __tablename__ = 'test'
-    col_a = sql.Column(sql.Integer, primary_key=True)
-    col_b = sql.Column(sql.Integer)
-
-  db = sqlutil.Database('sqlite://', base)
-  with db.Session() as s:
-    df = sqlutil.ModelToDataFrame(s, Table)
-
-  assert list(df.columns.values) == ['col_a', 'col_b']
-
-
-def test_QueryToDataFrame_explicit_column_names():
-  """Test that expected column names are set."""
-  base = declarative.declarative_base()
-
-  class Table(base):
-    __tablename__ = 'test'
-    col_a = sql.Column(sql.Integer, primary_key=True)
-    col_b = sql.Column(sql.Integer)
-
-  db = sqlutil.Database('sqlite://', base)
-  with db.Session() as s:
-    df = sqlutil.ModelToDataFrame(s, Table, ['col_b'])
-
-  assert list(df.columns.values) == ['col_b']
-
-
 def test_AllColumnNames_invalid_object():
   """TypeError raised when called on an invalid object."""