basic Python JSON Datetime convert issue

Question

i'm a python beginner and having an issue. Trying to pull API info and convert the extracted JSON time object to a datetime object in Python so I can run the date.weekday() function on it eventually (the overall goal is to extract all the dates from the API and see which the output by days - I plan on populating a empty dictionary once I can extract all the dates).

For some reason, even with my conditional statements, I'm still printing (2015, 04, 06) with all the zeroes. That's my problem.

I have a feeling I'm getting something basic wrong, and that there's also a better way to go about this than doing all the ifs/elses with the 0-padding in the date object.

here's my code so far:

from datetime import date
import datetime
import json
import requests

r = requests.get('https://api.github.com/repos/mbostock/d3/commits?since=2015-04-12330:00:000')
jsonoutput = r.json()
modified = (jsonoutput[0]["commit"]["author"]["date"])
#at this point, modified gives something like: "2015-04-06T22:28:16Z"

if modified[5] == 0:
    if modified[8] == 0:
        new_format = ("(" + modified[0:4] + ", " + modified[6] + ", " + modified[9] + ")")
        #with the particular jsonoutput[0] pulled here, this one should be triggered
    else:
        new_format = ("(" + modified[0:4] + ", " + modified[6] + ", " + modified[8:10] + ")")

else:
    if modified[8] == 0:
        new_format = ("(" + modified[0:4] + ", " + modified[5:7] + ", " + modified[9] + ")")
    else:
        new_format = ("(" + modified[0:4] + ", " + modified[5:7] + ", " + modified[8:10] + ")")

print(new_format)

print(date.weekday(datetime.date(new_format)))

NameError occurs when you try to use a variable that you have not yet declared Your code only declares new_format if modified[5] == 0 or modifies[5] == 1 -- but if modified[5] doesn't equal either, the variable is undefined. — jwilner
– jwilner, Commented Apr 20, 2015 at 0:34
ah, i just needed to change the second if to an else. But I'm still getting an output of (2015, 04, 06) with all the zeroes. any idea why @jwilner ? — SpicyClubSauce
– SpicyClubSauce, Commented Apr 20, 2015 at 0:36
@mu無 shouldn't that not matter with the string manipulation i'm doing? — SpicyClubSauce
– SpicyClubSauce, Commented Apr 20, 2015 at 0:40
@jwilner Given that modified is a timestamp, modified[5] could only be 0 or 1, so the elif vs else shouldn't matter right? — Anshul Goyal
– Anshul Goyal, Commented Apr 20, 2015 at 0:41
@mu無, the code was failing with a NameError because the variable was undefined. The variable was defined within both if and elif blocks; therefore, it never hit either block -- probably because modified[5] was a string, and 0 == "1" or 0 == "0" # False — jwilner
– jwilner, Commented Apr 20, 2015 at 0:45

Anshul Goyal · Accepted Answer · 2015-04-20 00:57:15Z

2

The error happens in your current code because new_format is defined as a string, while the datetime.date takes the arguments as integers. Also, since you compare the string "0" with the numerical 0, the modified is simply not created.

Instead of this:

new_format = ("(" + modified[0:4] + ", " + modified[6] + ", " + modified[8:10]) + ")")

do this:

new_format = (int(modified[0:4]), int(modified[5:7]), int(modified[8:10]))

The above will work with all of your cases, so you can remove the convoluted if-else blocks as well.

Alternatively, you could split this modeified string by "T", and then use another split by "-" to get the integer values:

new_format = map(int, modified.split("T")[0].split("-"))

You'll also need to unpack the list when passing as the argument, so your complete code becomes:

import json
import requests
from datetime import date

r = requests.get('https://api.github.com/repos/mbostock/d3/commits?since=2015-04-12330:00:000')
jsonoutput = r.json()
modified = jsonoutput[0]["commit"]["author"]["date"]
new_format = (int(modified[0:4]), int(modified[5:7]), int(modified[8:10]))
print(date.weekday(date(*new_format)))

Also, as others have already pointed out in their answers, it might be a better idea to dateutil.parser.parse than to write your own parsing logic. (dateutil is not a builtin package, you'll have to install it) :)

edited Apr 20, 2015 at 0:57

answered Apr 20, 2015 at 0:49

Anshul Goyal

78k42 gold badges161 silver badges196 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

SpicyClubSauce Over a year ago

thanks @mu 無 - looks like the dateutil.parser.parse works fine but I'm wondering why, after replacing my conditionals with your format, i'm still struggling to convert the output to a datetime.date object. datetime.date(new_format) is telling me an integer is required, not a tuple, but datetime.date(int(new_format) isn't giving me luck either. Sorry for all the absolutely beginner lvl questions man.

Anshul Goyal Over a year ago

@SpicyClubSauce I ran the current code in my answer, and it works allright, so can you re-check? Also, I've made a series of edits, so have a look at the answer in its current form.

SpicyClubSauce Over a year ago

hey @mu 無 - that works! what does the * do? I didnt have that in, and that gives an error when I don't have that in.

Anshul Goyal Over a year ago

@SpicyClubSauce That unpacks the tuple/list. Without the *, the list is passed as a single argument. With it, the elements of the list are passed as the multiple arguments. Check here. If that helped, don't forget to accept and upvote :)

Community · Accepted Answer · 2017-05-23 11:57:03Z

0

What you get from the json is actually a datetime representation in an ISO format

You can refer to this SO answer https://stackoverflow.com/a/15228038/58129 to convert the string

edited May 23, 2017 at 11:57

CommunityBot

11 silver badge

answered Apr 20, 2015 at 0:39

Anthony Kong

41.4k52 gold badges192 silver badges325 bronze badges

Comments

Jivan · Accepted Answer · 2015-04-20 00:57:02Z

0

You're trying to make your own parsing functions where Python has its own.

from dateutil import parser
from datetime import date

my_date = dateutil.parser.parse(modified)

is_week_day = date.weekday(my_date)

If dateutil is not installed on your machine, try pip install python-dateutil

However, if you want to go with Python's standard library:

from datetime import date, datetime
from time import strptime

mytime = strptime(modified, '%Y-%m-%dT%H:%M:%SZ')
my_date = datetime(*my_time[:6])

is_week_day = date.weekday(my_date)

edited Apr 20, 2015 at 0:57

answered Apr 20, 2015 at 0:44

Jivan

23.4k16 gold badges92 silver badges144 bronze badges

2 Comments

jwilner Over a year ago

I'm also just going to put in a shout out for the standard datetime library. Being explicit about expected inputs is always better, IMO, and datetime.datetime.strptime(date_string, "%Y-%m-%dT%H:%M:%sZ") is way more explicit. Plus, no third party libraries.

Jivan Over a year ago

@jwilner your (legitimate) shout has been heard

Collectives™ on Stack Overflow

basic Python JSON Datetime convert issue

3 Answers 3

4 Comments

Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

4 Comments

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related