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

taliarosen
taliarosen
2,492 Points
Posted by taliarosen
taliarosen
2,492 Points

problem on line 14

Challenge: Write a function named time_machine that takes an integer and a string of "minutes", "hours", "days", or "years". This describes a timedelta. Return a datetime that is the timedelta's duration from the starter datetime.

I'm getting the issue that date_element is not a valid argument. I assume this is because it is a string, but I don't know how to change that.

time_machine.py 
import datetime

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)
def time_machine(integer, date_element):
    if date_element == 'year':
        date_element = 'day'
        integer = integer*365
    timedelta = datetime.time(date_element=integer) 
    return(datetime.datetime.combine(starter, timedelta))

1 Answer

Steven Parker
Steven Parker
229,783 Points
Steven Parker
Steven Parker
229,783 Points

Python doesn't evaluate variables to use their contents as keywords, so the name "date_element" is not recognized as a valid keyword for the timedelta method. But what you can do is to create a dictionary using the variable and then use the unpacking operator (**) to create the keyword/argument combo:

    timedelta = datetime.timedelta(**{date_element: integer})

There's also two other issues:

  1. the keywords are all plural (for example: "days" instead of "day")
  2. the combine function doesn't expect a timedelta, but you can just add a datetime and a timedelta