Add starter code of Project: Exploring Near-Earth Objects

Exploring_Near_Earth_Objects/helpers.py

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+"""Convert datetimes to and from strings.
+
+NASA's dataset provides timestamps as naive datetimes (corresponding to UTC).
+
+The `cd_to_datetime` function converts a string, formatted as the `cd` field of
+NASA's close approach data, into a Python `datetime`
+
+The `datetime_to_str` function converts a Python `datetime` into a string.
+Although `datetime`s already have human-readable string representations, those
+representations display seconds, but NASA's data (and our datetimes!) don't
+provide that level of resolution, so the output format also will not.
+"""
+import datetime
+
+
+def cd_to_datetime(calendar_date):
+    """Convert a NASA-formatted calendar date/time description into a datetime.
+
+    NASA's format, at least in the `cd` field of close approach data, uses the
+    English locale's month names. For example, December 31st, 2020 at noon is:
+
+        2020-Dec-31 12:00
+
+    This will become the Python object `datetime.datetime(2020, 12, 31, 12, 0)`.
+
+    :param calendar_date: A calendar date in YYYY-bb-DD hh:mm format.
+    :return: A naive `datetime` corresponding to the given calendar date and time.
+    """
+    return datetime.datetime.strptime(calendar_date, "%Y-%b-%d %H:%M")
+
+
+def datetime_to_str(dt):
+    """Convert a naive Python datetime into a human-readable string.
+
+    The default string representation of a datetime includes seconds; however,
+    our data isn't that precise, so this function only formats the year, month,
+    date, hour, and minute values. Additionally, this function provides the date
+    in the usual ISO 8601 YYYY-MM-DD format to avoid ambiguities with
+    locale-specific month names.
+
+    :param dt: A naive Python datetime.
+    :return: That datetime, as a human-readable string without seconds.
+    """
+    return datetime.datetime.strftime(dt, "%Y-%m-%d %H:%M")