src/weather/csv_reader.py

@@ -0,0 +1,35 @@
+## @file csv_reader.py
+#  @brief Reads the weather data file with Python's built-in `csv` library.
+#
+#  This is the first half of the first lecture: the rows are read with
+#  `csv.reader` and the temperatures are converted to whole numbers. The module
+#  needs no third-party dependency.
+
+"""Reads the weather data file with the built-in csv library."""
+
+import csv
+from pathlib import Path
+
+from weather.constants import DATA_FILE, FILE_ENCODING, TEMP_COLUMN_INDEX
+
+
+def read_rows(path: Path | str = DATA_FILE) -> list[list[str]]:
+    """! @brief Read every row of a CSV file, the header row included.
+
+    @param path Path of the CSV file; the weather data file by default.
+    @return The rows, each a list of strings, in file order.
+    """
+    with open(path, newline="", encoding=FILE_ENCODING) as file:
+        return [row for row in csv.reader(file) if row]
+
+
+def read_temperatures(path: Path | str = DATA_FILE) -> list[int]:
+    """! @brief Read the temperatures of a weather CSV file as whole numbers.
+
+    The first row is the header and is skipped.
+
+    @param path Path of the CSV file; the weather data file by default.
+    @return The temperature of each data row, in file order.
+    """
+    data_rows = read_rows(path)[1:]
+    return [int(row[TEMP_COLUMN_INDEX]) for row in data_rows]