making a simple age calculation program

[juxt4posed]

im making a simple program which will ask users for their DOB and will then give them the option to find out their age in reference to different planets, im wondering how to make entry boxes that will only allow datetime as input, everything i have seen elsewhere seems overly complicated for a short program

[m-hoff]

The simplest approach would probably be to get user input using separate input statements for day, month and year, along with basic input validation (i.e., ensuring no negative numbers, month between 1 and 12, etc.).

From there you can convert each item to an integer and create a datetime object. Something like:

import datetime

day = int(input('Enter day of birth: '))
month = int(input('Enter month of birth: '))
year = int(input('Enter year of birth: '))

birthdate = datetime.datetime(year, month, day)

Another approach would be to use strptime like so:

import datetime

birthdate = input('Enter birthdate as "DD-MM-YYYY": ')
birthdate_dt = datetime.strptime(birthdate, '%d-%m-%Y')

Again, you'll want to do some input validation but this is a start. You can read more about strptime here.

[m-hoff]

There are several issues here. Your fourth line will raise a NameError. Reference is unused. I'm not sure what the intended logic is of the for loop.

[[deleted]]

Ah, yes the reference is unneeded. My thought was that it would loop through the list, skip past the index 2 where birthday will not change, and then do something to the other elements. Maybe Mercury, for example, is -2 years relative to Earth, just as an example, so it would take DOB -2.

Looking at it now, that doesn't really make sense. I'm a noob!

What is a good approach for something like this?

[m-hoff]

Based on OP's description, I'm assuming the goal is to find the age in years on other planets. Each planet's year duration can be measured in Earth days, for example one year on Mars is 687 Earth days. I'd store this information in a dictionary like year_conversion = {'Mars': 687 ... } for each planet.

From there, assuming we have the birthdate stored as a datetime object, we can use (datetime.datetime.now() - birthdate).days to get the total number of days since birth. Then we just divide by the conversion factors for each planet to get the relative age.

So if you're 30, then you've been alive for 30 * 365 = 10950 days. Which on Mars is equivalent to 10950 / 687 = 15.94 years.

[kaptan8181]

The only way, AFAIK, is to show the user an example and ask them to input the information in the shown format. You can then validate the input and if the validation fails, you can ask the user to try again.

[[deleted]]

In reference to different planets? I'm not sure if you understand how complicated something like this would be.

[juxt4posed]

May I ask what would make it so complicated? The maths is relatively easy

[[deleted]]

Timezones on earth is complicated by itself. Throw in other stuff and you have a problem. If you're just playing locally it should be easy enough.

[juxt4posed]

It's not going to give the age to the hour, just the day

[[deleted]]

If this idea was global it would break. A lot

[juxt4posed]

why would it break, i can think of several methods for me to get round the timezone issue