Create how_old_on_given_date.py

This is a short script to calculate the difference between input birthdate and a given date.

Author: mccright

how_old_on_given_date.py

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+import os
+import sys
+from datetime import *
+from dateutil.relativedelta import *
+from dateutil.tz import *
+import calendar
+
+# experimenting again with dateutil.relativedelta():
+# https://dateutil.readthedocs.io/en/stable/index.html
+
+# This function started with code from:
+# https://levlaz.org/pretty-print-relative-dates-in-python/
+# I later received a question about "how old was <indiviual-in-question> 
+# on a specific date?" and added the ability to specify a given date.
+# There is nothing special about "birthdate," it can be any starting date.
+def yourageattarget(birthyear: int, birthmonth: int, birthday: int, targetyear: int, targetmonth: int, targetday: int):
+    """
+    Description: Calculate the difference between input 
+    birthdate and a given date
+    Input: int birthyear, int birthmonth, int birthday, int targetyear, int targetmonth, int targetday.
+    Output: a string with diff in years months days.
+    """
+    try:
+        rd = relativedelta(datetime(int(targetyear), int(targetmonth), int(targetday)), datetime(int(birthyear), int(birthmonth), int(birthday)) )
+        years = f'{rd.years} years, ' if rd.years > 0 else ''
+        months = f'{rd.months} months, ' if rd.months > 0 else ''
+        days = f'{rd.days} days' if rd.days > 0 else ''
+    except Exception as e:
+        print(f"Exception doing relativedelta(): {e}")
+        sys.exit()
+    if f'{years}{months}{days}' == '':
+        print("Your input for birthdate cannot be today or in the future.")
+        print(f"Try again with <birthmonth> <birthday> <birthyear> <targetmonth> <targetday> <targetyear> on the command line.")
+        sys.exit()
+    else:
+        return f'{years}{months}{days}'
+
+
+def check_input(inputs: list) -> tuple:
+    if len(inputs) != 7:
+        print(f"Not enough arguments.\n Need <birthmonth> <birthday> <birthyear> <targetmonth> <targetday> <targetyear> on the command line.")
+        sys.exit(0)
+
+    if all(elements.isnumeric() for elements in (inputs[1:])) != True:
+        print(f"Some input was not numeric.\n Need <birthmonth> <birthday> <birthyear> <targetmonth> <targetday> <targetyear> on the command line.")
+        sys.exit(0)
+
+    if (int(inputs[1]) <= 12 and int(inputs[4]) <= 12):
+       # Do nothing. Month is valid.
+        birthmonth = int(inputs[1])
+        targetmonth = int(inputs[4])
+    else:
+        print("Invalid month. Your input for birthmonth was not between 1 and 12.")
+        print(f"Need <birthmonth> <birthday> <birthyear> <targetmonth> <targetday> <targetyear> on the command line.")
+        sys.exit(0)
+
+    if (int(inputs[2]) <= 31 and int(inputs[5]) <= 31):
+       # Do nothing. Gross day validation is OK.
+        birthday = int(inputs[2])
+        targetday = int(inputs[5])
+    else:
+        print("Invalid day. Your input for birthday was not between 1 and 31.")
+        print(f"Need <birthmonth> <birthday> <birthyear> <targetmonth> <targetday> <targetyear> on the command line.")
+        sys.exit(0)
+
+    if (len(inputs[3]) == 4 and len(inputs[6]) == 4):
+        birthyear = inputs[3]
+        targetyear = inputs[6]
+    else:
+        print("Invalid year length. \nYour input for birthyear was not 4 digits long.")
+        print(f"Need <birthmonth> <birthday> <birthyear> <targetmonth> <targetday> <targetyear> on the command line.")
+        sys.exit(0)
+
+    return birthyear, birthmonth, birthday, targetyear, targetmonth, targetday
+
+
+if __name__ == '__main__':
+    inputs: list = sys.argv
+    # Validate the input
+    birthyear, birthmonth, birthday, targetyear, targetmonth, targetday = check_input(inputs)
+
+    # birthhour = sys.argv[4]
+    print(f"                    ---------------------------")
+    print(f"birthmonth = {birthmonth}, birthday = {birthday}, birthyear = {birthyear}\r\ntargetmonth = {targetmonth}, targetday = {targetday}, targetyear = {targetyear}")
+    print(f"                    ---------------------------")
+    print(f"Given that input -> {yourageattarget(int(birthyear), int(birthmonth), int(birthday), int(targetyear), int(targetmonth), int(targetday))} old.")
+    print(f"                    ---------------------------")
+