added functions for selecting from dataframes and splitting a dataframe

pyproject.toml

@@ -27,8 +27,9 @@ classifiers = [
 ]
 
 dependencies = [
-
+    "pandas"
 ]
+
 [project.urls]
 Source = "https://git.cpi.imtek.uni-freiburg.de/holgi/sensospot_tools.git"
 

src/sensospot_tools/__init__.py

@@ -5,6 +5,4 @@ Some small tools for working with parsed Sensospot data.
 
 __version__ = "0.0.1"
 
-
-def test():
-    print("works")
+from .selection import split, select  # noqa: F401

src/sensospot_tools/helpers.py

@@ -0,0 +1,29 @@
+from typing import Any
+
+
+def ensure_list(something: Any) -> list[Any]:
+    """ensures the provided value is a list or encapsulated in a list
+
+    This is intended to use so that where column names should be provided
+    as a list could also be provided as a single column name
+
+    >>> ensure_list("abc")
+    ["abc"]
+
+    >>> ensure_list({"a", "b"})
+    ["a", "b"]
+
+    >>> ensure_list(1)
+    [1]
+
+    something:  the value to be in or the list
+    returns:    a list of whatever something is
+    """
+    # strings are iterables, so here is a special case for them
+    if isinstance(something, str):
+        return [something]
+    try:
+        return list(something)
+    except TypeError:
+        # something is not an iterable
+        return [something]

src/sensospot_tools/selection.py

@@ -0,0 +1,74 @@
+from typing import Any, Iterator
+
+import pandas
+
+
+def select(
+    data: pandas.DataFrame, column: str, value: Any
+) -> pandas.DataFrame:
+    """selects a portion of a dataframe based by a value in a column
+
+    Example:
+    >>> print(data)
+          category  value
+        0      dog      1
+        1      cat      2
+        2    horse      3
+        3      cat      4
+
+    >>> print(select(data, "category", "cat"))
+          category  value
+        1      cat      2
+        3      cat      4
+
+
+    data:    a data DataFrame to select from
+    column:  name of a column in a dataframe
+    value:   rows with this value in the column will be selected
+    returns: a copy of the DataFrame that has the value in the column
+    """
+    selector = data[column] == value
+    return data.loc[selector].copy()
+
+
+def split(
+    data: pandas.DataFrame, column: str
+) -> Iterator[tuple[Any, pandas.DataFrame]]:
+    """splits a data frame by unique values in a column
+
+    returns an iterator where each result is key-value-pair. The key is the
+    unique value used for the split, the value is a slice of the dataframe
+    selected by the unique value contained in the column
+
+    Example:
+
+    >>> print(data)
+          category  value
+        0      dog      1
+        1      cat      2
+        2    horse      3
+        3      cat      4
+
+    >>> result = dict( split(data, column="category") )
+
+    >>> print(result["dog"])
+          category  value
+        0      dog      1
+
+    >>> print(result["cat"])
+          category  value
+        1      cat      2
+        3      cat      4
+
+    >>> print(result["horse"])
+          category  value
+        2    horse      3
+
+    data:   DataFrame to process
+    column: column identifier to split on unique values
+    yields: key-value-pairs of
+            keys: one unique value
+            values: slice of the dataframe that contains the unique value
+    """
+    unique_values = data[column].unique()
+    return ((value, select(data, column, value)) for value in unique_values)

tests/test_helpers.py

@@ -0,0 +1,18 @@
+import pytest
+
+
+@pytest.mark.parametrize(
+    "provided, expected",
+    [
+        ("abc", ["abc"]),
+        (tuple("abc"), ["a", "b", "c"]),
+        ({"a": 1, "b": 2}, ["a", "b"]),
+        (1, [1]),
+    ],
+)
+def test_helpers_ensure_list(provided, expected):
+    from sensospot_tools.helpers import ensure_list
+
+    result = ensure_list(provided)
+
+    assert result == expected

tests/test_selection.py

@@ -0,0 +1,39 @@
+import pytest
+
+CSV_DATA = """
+category	value
+dog	3
+cat	55
+horse	35
+cat	60
+horse	9
+"""
+
+
+@pytest.fixture
+def example():
+    import io
+
+    import pandas
+
+    buffer = io.StringIO(CSV_DATA.strip())
+    yield pandas.read_csv(buffer, sep="\t")
+
+
+def test_selection_select(example):
+    from sensospot_tools.selection import select
+
+    result = select(example, "category", "horse")
+    assert list(result["category"]) == ["horse", "horse"]
+    assert list(result["value"]) == [35, 9]
+
+
+def test_selection_split(example):
+    from sensospot_tools.selection import split
+
+    result = dict(split(example, "category"))
+
+    assert sorted(result.keys()) == ["cat", "dog", "horse"]
+    assert list(result["cat"]["value"]) == [55, 60]
+    assert list(result["dog"]["value"]) == [3]
+    assert list(result["horse"]["value"]) == [35, 9]

tests/test_sensospot_tools.py

@@ -1,41 +1,4 @@
-""" Stub file for testing the project
-
-There are three predefined ways to run tests:
-
-make test:
-    runs only unit tests, that are not marked with "fun" (for functional test)
-    in a random order. If a test failed before, only the failed tests will be
-    run. This is intended to be the default testing method while developing.
-
-make testall:
-    runs unit tests and functional tests in random order. Will give a complete
-    overview of the test suite.
-
-make coverage:
-    runs only tests marked with "fun" (for functional tests) and generates a
-    coverage report for the test run. The idea is to check the test coverage
-    only on functinal tests to see if a) everything is as much covered as
-    possible and b) to find dead code that is not called in end-to-end tests.
-
-all three test strategies will run "make lint" before to catch easily made
-mistakes.
-"""
-
-import pytest
-
-
-def test_example_unittest():
-    """example unittest - try importing the project
-
-    will be run by 'make test' and 'make testall' but not 'make  coverage'
-    """
-    import sensospot_tools  # noqa: F401
-
-
-@pytest.mark.functional
-def test_example_functional_test():
-    """example unittest
-
-    will be by 'make  coverage' and 'make testall' but not 'make test'
-    """
-    assert True
+def test_api():
+    """test if the provided functionality is importable"""
+    from sensospot_tools import split  # noqa: F401
+    from sensospot_tools import select  # noqa: F401