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Python Dates and Times in Python (2014) Dates and Times strftime & strptime

jessicakincaid
jessicakincaid
21,833 Points
Posted by jessicakincaid
jessicakincaid
21,833 Points

I'm stuck in the datetime strings challenge. I get the right result in my workspace, but my solution is incorrect.

I made a new file and tested this line by line in my workspace, and it returned the right result there. Surely it's something obvious. Thank you in advance for your help! 

import datetime

"""Create a function named to_string that takes a datetime
and gives back a string in the format "24 September 2012"."""


def to_string(datetime_object):
    datetime_object = input('Please enter a date as (MM-DD-YY)')

    object_digits =  datetime.datetime.strptime(datetime_object, '%m-%d-%y')
    return object_digits.strftime('%d %B %Y')

```timestrings.py
## Examples
# to_string(datetime_object) => "24 September 2012"
# from_string("09/24/12 18:30", "%m/%d/%y %H:%M") => datetime
import datetime

def to_string(datetime_object):
    datetime_object = input('Please enter a date as (MM-DD-YY)')
    object_digits =  datetime.datetime.strptime(datetime_object, '%m-%d-%y')
    return object_digits.strftime('%d %B %Y')
jessicakincaid
jessicakincaid
21,833 Points
jessicakincaid
jessicakincaid
21,833 Points

I only submitted the function once, I formatted it above for sharing and it displayed twice.

5 Answers

Jeff Muday
MOD
Jeff Muday
Treehouse Moderator 28,720 Points
Jeff Muday
Jeff Muday
Treehouse Moderator 28,720 Points

Fred Gablick is correct, the automated grader uses Python's unittest library, thus it automatically feeds the input and expects a particular output. Using Python's input() method will keep the Challenge automated grader from working properly.

Also... this challenge is designed for the student to recognize that datetime's strftime and strptime are each other's inverse.

Jessica did a good job of recognizing how part 1 should be coded. Nice work! I show a slightly simpler way to do part 1 below which avoids the explicit creation of an extra datetime object.

I left part 2 of the challenge for Jessica to solve.

Here is the official Python document on strptime and strftime linked below

https://docs.python.org/3/library/datetime.html#strftime-and-strptime-behavior

import datetime

def to_string(datetime_object):
    # part 1 of challenge: return a string from datetime_object
    return datetime.datetime.strftime(datetime_object, '%d %B %Y')

def from_string(date_string, date_format):
    # part 2 of challenge: return a datetime object from a date_string and a date_format
    ... fill in your code here ...
Fred Gablick
Fred Gablick
5,840 Points
Fred Gablick
Fred Gablick
5,840 Points

The first thing that jumped out is that you're defining your datetime_object twice - once as the function parameter, and then again inside the function. It works fine for me if I move the input line outside of the function:

import datetime

"""Create a function named to_string that takes a datetime
and gives back a string in the format "24 September 2012"."""


def to_string(datetime_object):
    object_digits =  datetime.datetime.strptime(datetime_object, '%m-%d-%y')
    return object_digits.strftime('%d %B %Y')

datetime_object = input('Please enter a date as (MM-DD-YY)')
print (to_string(datetime_object))

*Disclaimer - I don't know the lesson to which you refer, I just saw that and wanted to bring it to your attention

jessicakincaid
jessicakincaid
21,833 Points
jessicakincaid
jessicakincaid
21,833 Points

Thank you, Fred Gablick. It's encouraging to know that the code worked for you after you moved the input statement! I removed it but my answer was still incorrect. After "Bummer!" the checker elaborated further:

"Exception: We caught an EOFError exception! Do you have a call to input() in your code? Sorry, but the input() function doesn't work in code challenges! Please remove the call to input(), and try again." The code challenge is called "strftime and strptime" and is the first of a two-part challenge in the Python Dates & Times course.

Fred Gablick
Fred Gablick
5,840 Points
Fred Gablick
Fred Gablick
5,840 Points

Ahh! Have you tried taking the input() line completely out of your challenge code? A lot of the challenges aren't looking for complete, working code, and know how to check for exactly what they ask.

jessicakincaid
jessicakincaid
21,833 Points
jessicakincaid
jessicakincaid
21,833 Points

You are right on. I finally received a correct answer after I brought the function down to two lines, with no input() line. It seems to me that the checker is designed to make us write as minimal code as possible. Have you read "The Zen of Python" by Tim Peters? I learned about it in Kenneth's Write Better Python course. It's there if you open a Python shell open and type 

>>> import this
Fred Gablick
Fred Gablick
5,840 Points
Fred Gablick
Fred Gablick
5,840 Points

I'm embarrassed that I had NOT seen that before; thanks for sharing. I'll have to admit - I disagree with a lot of it, but overall it's good advice.

I should also admit that I struggle with making my code "Pythonic," so take my disagreement with a grain of salt. I have been thinking more and more that I need a mentor.