feat(size_2_square): add function to calculate the square needed for …

…the size

README.md

@@ -53,6 +53,7 @@ As of *v0.2*, plots are not yet tested in the travis build.
 * 0.2.5
     * ADD: Function ``log_df`` to print function results during method chaining.
     * ADD: Function ``avg_dicts`` to make the average of multiple similar dictionaries.
+    * ADD: Function ``size_2_square`` to calculate the square needed for the given size (e.g. in subplots).
     * ADD: Option ``with_identity`` to plot an identity line in the ``plot_true_vs_pred`` function.
     * ADD: Option ``with_determination`` to plot the coefficient of determination in the ``plot_true_vs_pred`` function.
     * ADD: Function ``size_to_square`` to calculate automatically the size of the side of a square needed to store all the elements.

bff/__init__.py

@@ -18,6 +18,7 @@
     normalization_pd,
     parse_date,
     read_sql_by_chunks,
+    size_2_square,
     sliding_window,
     value_2_list,
 )
@@ -38,6 +39,7 @@
     'parse_date',
     'plot',
     'read_sql_by_chunks',
+    'size_2_square',
     'sliding_window',
     'FancyConfig',
     'value_2_list',

bff/fancy.py

@@ -631,6 +631,28 @@ def read_sql_by_chunks(sql: str, cnxn, params: Union[List, Dict, None] = None,
     return res
 
 
+def size_2_square(n: int) -> Tuple[int, int]:
+    """
+    Return the size of the side to create a square able to contain n elements.
+
+    This is mainly used to have the correct sizes of the sides when creating squared subplots.
+
+    Parameters
+    ----------
+    n: int
+        Number of elements that need to fit inside the square.
+
+    Returns
+    -------
+    Tuple of int
+        Tuple of int with the size of each part of the square.
+        Both element of the tuple are similar.
+    """
+    size_float = math.sqrt(n)
+    size_int = int(size_float) if size_float.is_integer() else math.ceil(size_float)
+    return (size_int, size_int)
+
+
 def sliding_window(sequence: Sequence, window_size: int, step: int):
     """
     Apply a sliding window over the sequence.

tests/test_fancy.py

@@ -16,7 +16,7 @@
 
 from bff.fancy import (avg_dicts, cast_to_category_pd, concat_with_categories, get_peaks,
                        idict, kwargs_2_list, log_df, mem_usage_pd, normalization_pd,
-                       parse_date, sliding_window, value_2_list)
+                       parse_date, size_2_square, sliding_window, value_2_list)
 
 
 class TestFancy(unittest.TestCase):
@@ -298,6 +298,16 @@ def dummy_function_custom(**kwargs):
         self.assertEqual(dummy_function(date='wrong format')['date'],
                          'wrong format')
 
+    def test_size_2_square(self):
+        """
+        Test of the `size_2_square` function.
+        """
+        # Test when result is  a square.
+        self.assertEqual(size_2_square(9), (3, 3))
+
+        # Test when not a square.
+        self.assertEqual(size_2_square(10), (4, 4))
+
     def test_sliding_window(self):
         """
         Test of the `sliding_window` function.