Add YEAR(), MONTH() and EOMONTH()

koala/excellib.py

@@ -9,9 +9,11 @@
 from __future__ import absolute_import, division
 
 import numpy as np
-from datetime import datetime, date
+import datetime
 from math import log, ceil
 from decimal import Decimal, ROUND_UP, ROUND_HALF_UP
+from calendar import monthrange
+from dateutil.relativedelta import relativedelta
 
 from openpyxl.compat import unicode
 
@@ -99,11 +101,14 @@
     "ROUNDUP",
     "POWER",
     "SQRT",
-    "TODAY"
+    "TODAY",
+    "YEAR",
+    "MONTH",
+    "EOMONTH",
 ]
 
 CELL_CHARACTER_LIMIT = 32767
-EXCEL_EPOCH = datetime.strptime("1900-01-01", '%Y-%m-%d').date()
+EXCEL_EPOCH = datetime.datetime.strptime("1900-01-01", '%Y-%m-%d').date()
 
 ######################################################################################
 # List of excel equivalent functions
@@ -419,6 +424,48 @@ def mod(nb, q): # Excel Reference: https://support.office.com/en-us/article/MOD-
         return nb % q
 
 
+def eomonth(start_date, months): # Excel reference: https://support.office.com/en-us/article/eomonth-function-7314ffa1-2bc9-4005-9d66-f49db127d628
+    if not is_number(start_date):
+        return ExcelError('#VALUE!', 'start_date %s must be a number' % str(start_date))
+    if start_date < 0:
+        return ExcelError('#VALUE!', 'start_date %s must be positive' % str(start_date))
+
+    if not is_number(months):
+        return ExcelError('#VALUE!', 'months %s must be a number' % str(months))
+
+    y1, m1, d1 = date_from_int(start_date)
+    start_date_d = datetime.date(year=y1, month=m1, day=d1)
+    end_date_d = start_date_d + relativedelta(months=months)
+    y2 = end_date_d.year
+    m2 = end_date_d.month
+    d2 = monthrange(y2, m2)[1]
+    res = int(int_from_date(datetime.date(y2, m2, d2)))
+
+    return res
+
+
+def year(serial_number): # Excel reference: https://support.office.com/en-us/article/year-function-c64f017a-1354-490d-981f-578e8ec8d3b9
+    if not is_number(serial_number):
+        return ExcelError('#VALUE!', 'start_date %s must be a number' % str(serial_number))
+    if serial_number < 0:
+        return ExcelError('#VALUE!', 'start_date %s must be positive' % str(serial_number))
+
+    y1, m1, d1 = date_from_int(serial_number)
+
+    return y1
+
+
+def month(serial_number): # Excel reference: https://support.office.com/en-us/article/month-function-579a2881-199b-48b2-ab90-ddba0eba86e8
+    if not is_number(serial_number):
+        return ExcelError('#VALUE!', 'start_date %s must be a number' % str(serial_number))
+    if serial_number < 0:
+        return ExcelError('#VALUE!', 'start_date %s must be positive' % str(serial_number))
+
+    y1, m1, d1 = date_from_int(serial_number)
+
+    return m1
+
+
 def count(*args): # Excel reference: https://support.office.com/en-us/article/COUNT-function-a59cd7fc-b623-4d93-87a4-d23bf411294c
     l = list(args)
 
@@ -590,10 +637,10 @@ def date(year, month, day): # Excel reference: https://support.office.com/en-us/
 
     year, month, day = normalize_year(year, month, day) # taking into account negative month and day values
 
-    date_0 = datetime(1900, 1, 1)
-    date = datetime(year, month, day)
+    date_0 = datetime.datetime(1900, 1, 1)
+    date = datetime.datetime(year, month, day)
 
-    result = (datetime(year, month, day) - date_0).days + 2
+    result = (datetime.datetime(year, month, day) - date_0).days + 2
 
     if result <= 0:
         return ExcelError('#VALUE!', 'Date result is negative')
@@ -980,7 +1027,7 @@ def sqrt(number):
 
 # https://support.office.com/en-ie/article/today-function-5eb3078d-a82c-4736-8930-2f51a028fdd9
 def today():
-    reference_date = datetime.today().date()
+    reference_date = datetime.datetime.today().date()
     days_since_epoch = reference_date - EXCEL_EPOCH
     # why +2 ?
     # 1 based from 1900-01-01

koala/utils.py

@@ -5,6 +5,7 @@
 import collections
 import numbers
 import re
+import datetime as dt
 from six import string_types
 
 from openpyxl.compat import unicode
@@ -131,7 +132,7 @@ def resolve_range(rng, should_flatten = False, sheet=''):
             start_row = start
             end_col = "XFD"
             end_row = end
-        else:    
+        else:
             sh, start_col, start_row = split_address(start)
             sh, end_col, end_row = split_address(end)
 
@@ -407,11 +408,17 @@ def date_from_int(nb):
             if nb > max_days:
                 nb -= max_days
             else:
-                current_day = nb
+                current_day = int(nb)
                 nb = 0
 
     return (current_year, current_month, current_day)
 
+def int_from_date(date):
+    temp = dt.date(1899, 12, 30)    # Note, not 31st Dec but 30th!
+    delta = date - temp
+
+    return float(delta.days) + (float(delta.seconds) / 86400)
+
 def criteria_parser(criteria):
 
     if is_number(criteria):

requirements.txt

@@ -4,3 +4,4 @@ numpy==1.14.2
 Cython==0.28.2
 lxml==4.1.1
 six==1.11.0
+python-dateutil==2.8.0

tests/excel/test_functions.py

@@ -719,11 +719,14 @@ def test_first_argument_validity(self):
     def test_positive_integers(self):
         self.assertEqual(sqrt(16), 4)
 
+    def test_float(self):
+        self.assertEqual(sqrt(.25), .5)
+
 
 class Test_Today(unittest.TestCase):
 
-    EXCEL_EPOCH = datetime.strptime("1900-01-01", '%Y-%m-%d').date()
-    reference_date = datetime.today().date()
+    EXCEL_EPOCH = datetime.datetime.strptime("1900-01-01", '%Y-%m-%d').date()
+    reference_date = datetime.datetime.today().date()
     days_since_epoch = reference_date - EXCEL_EPOCH
     todays_ordinal = days_since_epoch.days + 2
 
@@ -740,3 +743,29 @@ def test_first_argument_validity(self):
 
     def test_concatenate(self):
         self.assertEqual(concatenate("Hello", " ", "World!"), "Hello World!")
+
+
+class Test_Year(unittest.TestCase):
+
+    def test_results(self):
+        self.assertEqual(year(43566), 2019)  # 11/04/2019
+        self.assertEqual(year(43831), 2020)  # 01/01/2020
+        self.assertEqual(year(36525), 1999)  # 31/12/1999
+
+
+class Test_Month(unittest.TestCase):
+
+    def test_results(self):
+        self.assertEqual(month(43566), 4)  # 11/04/2019
+        self.assertEqual(month(43831), 1)  # 01/01/2020
+        self.assertEqual(month(36525), 12)  # 31/12/1999
+
+
+class Test_Eomonth(unittest.TestCase):
+
+    def test_results(self):
+        self.assertEqual(eomonth(43566, 2), 43646)  # 11/04/2019, add 2 months
+        self.assertEqual(eomonth(43831, 5), 44012)  # 01/01/2020, add 5 months
+        self.assertEqual(eomonth(36525, 1), 36556)  # 31/12/1999, add 1 month
+        self.assertEqual(eomonth(36525, 15), 36981)  # 31/12/1999, add 15 month
+        self.assertNotEqual(eomonth(36525, 15), 36980)  # 31/12/1999, add 15 month