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Python Dates and Times in Python (2014) Let's Build a Timed Quiz App Harder Time Machine

Kenneth Bagwell Jr
Kenneth Bagwell Jr
3,698 Points
Posted by Kenneth Bagwell Jr
Kenneth Bagwell Jr
3,698 Points

time delta coversion

how do I covert this time to a time delta

time_machine.py 
import datetime

def time_machine(num, "days"):
    time = 

starter = datetime.datetime(2015, 10, 21, 16, 29)

# Remember, you can't set "years" on a timedelta!
# Consider a year to be 365 days.

## Example
# time_machine(5, "minutes") => datetime(2015, 10, 21, 16, 34)

2 Answers

Asher Orr
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.a{fill-rule:evenodd;}techdegree seal-36
Asher Orr
Python Development Techdegree Graduate 9,409 Points
Asher Orr
.a{fill-rule:evenodd;}techdegree seal-36
Asher Orr
Python Development Techdegree Graduate 9,409 Points

Hi Kenneth!

The function, time_machine, should take an integer and a string of "minutes", "hours", "days", or "years". First:

def time_machine(num, "days"):

In your code above, the second parameter is literally the string "days". You want the parameter to represent any string that's passed into it- days, minutes, hours, or years. You should change that parameter to something generic, like:

def time_machine(num, time_unit):

Now, let's move on to the body of your function.

Your parameters are a number and a time unit that represent a timedelta (a gap in time.) When you click "Check Work," the Treehouse checker will pass in arguments like this:

def time_machine(5, "hours")

If you watch Kenneth's lesson on timedeltas, you'll see that you can add them to other datetime objects to get a new time.

For example:

now = datetime.datetime.now()
# >> now 
datetime.datetime(2022, 7, 12, 12, 10, 31, 459833)
# here are what those numbers represent: year, month, day, hour, minute, second, microsecond.
new_object = now + datetime.timedelta(days=3)
# >> new_object
datetime.datetime(2022, 7, 15, 12, 10, 31, 459833)
#see the difference?
#we added 3 days to a datetime object (now)
#that's why the 12 (the third number in the parentheses, representing the day) became a 15.

The challenge asks to return a datetime object that is the timedelta's duration from the starter datetime.

Here's a simpler way to think about it:

Step 1: Convert your parameters to a datetime object that's a timedelta.

  • Hint: you may need to use multiple if statements, since "minutes", "hours", "days", or "years" could be passed in for the time_unit parameter.

Step 2: Make a variable that stores an operation where you add that datetime object to the variable "starter".

  • That's how you get the timedelta's duration from the starter datetime.

Step 3: Return that variable

I hope this helps. Let me know if you have questions!

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

When you define a function, the parameter names should not have quotes around them (but when the function is called, it's OK for the argument to be a quoted literal string).

To make a timedelta using a num of units you would do something like mydelta = datetime.timedelta(units=num). But remember that timedelta doesn't recognise "years" for units, so you'll need to handle that specially.