Create a DataFrame from a dictionary and export it to a CSV file

Task: MIL-004#1
Task: MIL-004#2

src/weather/export.py

@@ -0,0 +1,39 @@
+## @file export.py
+#  @brief Creates a `DataFrame` from a dictionary and exports it to a CSV file.
+#
+#  This is the end of the second lecture: the table of students and scores is
+#  built from a dictionary and written with `DataFrame.to_csv`. Nothing is
+#  written unless `export_frame` is called with a path or its default name.
+
+"""Creates a DataFrame from a dictionary and exports it to a CSV file."""
+
+from pathlib import Path
+
+import pandas
+
+from weather.constants import (
+    COLUMN_SCORES,
+    COLUMN_STUDENTS,
+    EXPORT_FILE_NAME,
+    SCORES,
+    STUDENTS,
+)
+
+
+def create_scores_frame() -> pandas.DataFrame:
+    """! @brief Create the table of students and scores from a dictionary.
+
+    @return A table with the columns `students` and `scores`, one row per student.
+    """
+    data_dict = {COLUMN_STUDENTS: list(STUDENTS), COLUMN_SCORES: list(SCORES)}
+    return pandas.DataFrame(data_dict)
+
+
+def export_frame(frame: pandas.DataFrame, path: Path | str = EXPORT_FILE_NAME) -> None:
+    """! @brief Write a table to a CSV file, the row index included.
+
+    @param frame The table to write.
+    @param path Path of the file to write; `new_data.csv` in the working folder
+           by default.
+    """
+    frame.to_csv(path)