feat(value_2_list): add function to cast single value to a list

.pylintrc

@@ -139,6 +139,7 @@ disable=print-statement,
         deprecated-sys-function,
         exception-escape,
         comprehension-escape,
+        logging-format-interpolation,
         logging-fstring-interpolation
 
 # Enable the message, report, category or checker with the given id(s). You can

README.md

@@ -50,6 +50,9 @@ As of *v0.2*, plots are not yet tested in the travis build.
 
 ## Release History
 
+* 0.2.2
+    * FIX: Function ``value_2_list`` renamed to ``kwargs_2_list``.
+    * ADD: Function ``value_2_list`` to cast a single value.
 * 0.2.1
     * ADD: Function ``plot_counter`` to plot counter as bar plot.
 * 0.2.0

bff/__init__.py

@@ -16,6 +16,7 @@
     parse_date,
     read_sql_by_chunks,
     sliding_window,
+    value_2_list,
 )
 
 from .config import FancyConfig
@@ -33,6 +34,7 @@
     'read_sql_by_chunks',
     'sliding_window',
     'FancyConfig',
+    'value_2_list',
 ]
 
 # Logging configuration.

bff/fancy.py

@@ -11,6 +11,7 @@
 from typing import Any, Callable, Dict, Hashable, List, Sequence, Set, Union
 from dateutil import parser
 from scipy import signal
+import numpy as np
 import pandas as pd
 
 LOGGER = logging.getLogger(__name__)
@@ -284,8 +285,7 @@ def kwargs_2_list(**kwargs) -> Dict[str, Sequence]:
     {'countries': ['Swiss', 'Spain']}
     """
     for k, v in kwargs.items():
-        if not isinstance(v, collections.abc.Sequence) or isinstance(v, str):
-            kwargs[k] = [v]
+        kwargs[k] = value_2_list(v)
     return kwargs
 
 
@@ -532,3 +532,36 @@ def sliding_window(sequence: Sequence, window_size: int, step: int):
     if mod:
         start = len(sequence) - (window_size - step) - mod
         yield sequence[start:]
+
+
+def value_2_list(value: Any) -> Sequence:
+    """
+    Convert a single value into a list with a single value.
+
+    If the value is alredy a sequence, it is returned without modification.
+    Type `np.ndarray` is not put inside another sequence.
+
+    Strings are not considered as a sequence in this scenario.
+
+    Parameters
+    ----------
+    value
+        Value to convert to a sequence.
+
+    Returns
+    -------
+    sequence
+        Value put into a sequence.
+
+    Examples
+    --------
+    >>> value_2_list(42)
+    [42]
+    >>> value_2_list('Swiss')
+    ['Swiss']
+    >>> value_2_list('Swiss')
+    ['Swiss']
+    """
+    if (not isinstance(value, (collections.abc.Sequence, np.ndarray)) or isinstance(value, str)):
+        value = [value]
+    return value

doc/source/fancy.rst

@@ -21,4 +21,5 @@ All of bff's functions.
    bff.plot.plot_true_vs_pred
    bff.read_sql_by_chunks
    bff.sliding_window
+   bff.value_2_list
 

tests/test_fancy.py

@@ -6,14 +6,15 @@
 import datetime
 import unittest
 import unittest.mock
+import matplotlib.pyplot as plt
 import numpy as np
 from numpy.testing import assert_array_equal
 import pandas as pd
 from pandas.api.types import CategoricalDtype
 import pandas.util.testing as tm
 
 from bff.fancy import (cast_to_category_pd, concat_with_categories, get_peaks, idict,
-                       mem_usage_pd, parse_date, kwargs_2_list, sliding_window)
+                       kwargs_2_list, mem_usage_pd, parse_date, sliding_window, value_2_list)
 
 
 class TestFancy(unittest.TestCase):
@@ -277,6 +278,28 @@ def test_sliding_window(self):
         with self.assertRaises(ValueError):
             list(sliding_window('abc', 4, 1))
 
+    def test_value_2_list(self):
+        """
+        Test of the `value_2_list` function.
+        """
+        # A list should remain a list.
+        self.assertEqual(value_2_list([1, 2, 3]), [1, 2, 3])
+        # A single integer should result in a list with one integer.
+        self.assertEqual(value_2_list(42), [42])
+        # A single string should result in a list with one string.
+        self.assertEqual(value_2_list('John Doe'), ['John Doe'])
+        # A tuple should remain a tuple.
+        self.assertEqual(value_2_list(('Jane Doe', 14)), ('Jane Doe', 14))
+        # A dictionary should result in a list with the dictionary.
+        self.assertEqual(value_2_list({'name': 'John Doe', 'age': 42}),
+                         [{'name': 'John Doe', 'age': 42}])
+        # A single axis should be put in a list.
+        __, axes_a = plt.subplots(nrows=1, ncols=1)
+        self.assertEqual(len(value_2_list(axes_a)), 1)
+        # A list of axis (`np.ndarray`) should not change.
+        __, axes_b = plt.subplots(nrows=2, ncols=1)
+        self.assertEqual(len(value_2_list(axes_b)), 2)
+
 
 if __name__ == '__main__':
     unittest.main()