add solutions week 259 260 task 1 in python

1 files changed, 47 insertions, 0 deletions

diff --git a/challenge-259/steven-wilson/python/ch-1.py b/challenge-259/steven-wilson/python/ch-1.py
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+++ b/challenge-259/steven-wilson/python/ch-1.py
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+#!/usr/bin/env python3
+
+from datetime import timedelta
+from datetime import date
+
+
+def banking_day_offset(start_date, offset, bank_holidays=None):
+    ''' Given a number (of days) and a start date, return the number (of days)
+    adjusted to take into account non-banking days. In other words: convert a
+    banking day offset to a calendar day offset.
+
+    >>> banking_day_offset('2018-06-28', 3, ['2018-07-03'])
+    '2018-07-04'
+    >>> banking_day_offset('2018-06-28', 3)
+    '2018-07-03'
+    '''
+    if bank_holidays is None:
+        bank_holidays = []
+
+    if not isinstance(offset, int) or offset < 0:
+        raise ValueError(f"{offset} is not a valid offset")
+
+    try:
+        odate = date.fromisoformat(start_date)
+    except ValueError:
+        raise ValueError(f"{start_date} is not a valid iso format start date")
+
+    for holiday in bank_holidays:
+        try:
+            date.fromisoformat(holiday)
+        except ValueError:
+            raise ValueError(f"{holiday} is not a valid iso format bank holiday")
+
+    weekend = [5, 6]
+
+    for _ in range(offset):
+        odate += timedelta(days=1)
+        while odate.weekday() in weekend or odate.isoformat() in bank_holidays:
+            odate += timedelta(days=1)
+
+    return odate.isoformat()
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()