So this question is more of best way to handle this sort of input in python. Here is an example of input date 2018-12-31 23:59:59.999999. The millisecond part may or may not be part of input.
I am currently using this code to convert this to datetime
input_ts = datetime.datetime.strptime(input_str, '%Y-%m-%dT%H:%M:%S.%f')
But the problem in this case is that it will throw an exception if input string doesn't contain milliseconds part i.e., 2018-12-31 23:59:59
In Java, I could have approached this problem in two ways. (its a pseudo explanation, without taking into account of small boundary checks)
(preferred approach). Check the input string length. if its less than 19 then it is missing milliseconds. Append .000000 to it.
(not preferred). Let the main code parse the string, if it throws an exception, then parse it with new time format i.e., %Y-%m-%dT%H:%M:%S
The third approach could be just strip off milliseconds.
I am not sure if python has anything built-in to handle these kind of situations. Any suggestions?
You could use python-dateutil library, it is smart enough to parse most of the basic date formats.
import dateutil.parser
dateutil.parser.parse('2018-12-31 23:59:59.999999')
dateutil.parser.parse('2018-12-31 23:59:59')
In case you don't want to install any external libraries, you could iterate over list of different formats as proposed in this answer.
from datetime import datetime # import datetime class from datetime package
dt = datetime.now() # get current time
dt1 = dt1.strftime('%Y-%m-%d %H:%M:%S') # converting time to string
dt3 = dt2.strptime('2018/5/20','%Y/%m/%d') # converting a string to specified time
Related
from dateutil.parser import parse
parse(‘2m’) - treating it as a datetime
I’m testing a few terms like 2w, 2y, 2m and some other date formats received in a string to check whether a given string has a date of any format.
Everything works fine except ‘2m’
It’s treating it as 2 minutes past, I don’t want to treat it as a date format.
Please can anyone help to resolve this issue
I tried to submit a time var with value of 2016-03-12T01:47:57+00:00 in a timestamp field, it gives me error saying to check the syntax for errors, however when I use a function to normalize the date
t = datetime.datetime.strptime(data['time'], '%Y-%m-%dT%H:%M:%SZ').strftime('%Y-%m-%d:%H:%M:%S')
I get an error like this.
time data '2016-03-12T01:47:57+00:00' does not match format '%Y-%m-%dT%H:%M:%SZ'
What's causing your problem has already been clarified by others, but please allow me to suggest my favorite solution for cases such as yours:
from dateutil import parser
parser.parse(data['time'])
More about the dateutil module here.
There are a few problems here:
The %Z (note the captial Z!) is for time zone, for example GMT. I
think you want the lower case option: %z, which is for UTC offset.
You can read here in the docs what all the options do :)
https://docs.python.org/2/library/datetime.html#strftime-and-strptime-behavior
You need the % symbol before each option. You cannot write %Sz, you must write %S%z. Otherwise Python is trying to match something like 2016-03-12T01:47:57z, rather than 2016-03-12T01:47:57+00:00
Unfortunately, you can't use the %z option with strptime, see this answer:
ISO to datetime object: 'z' is a bad directive
My solution:
It sounds like you don't even want to use the UTC offset. That's fine! If you can't change the way your date string is generated, perhaps this is the best option (though it's maybe a little dirty):
t = datetime.datetime.strptime(data['time'][:-6], '%Y-%m-%dT%H:%M:%S')
This will remove the UTC offset from the string.
If you can change the way your datetime string is being generated, that would be a better solution, but I realise you might not be able to do so.
I hope this helps!
This question already has answers here:
Convert weird Python date format to readable date
(2 answers)
Closed 7 years ago.
I'm importing data from an Excel spreadsheet into python. My dates are coming through in a bizarre format of which I am not familiar and cannot parse.
in excel: (7/31/2015)
42216
after I import it:
u'/Date(1438318800000-0500)/'
Two questions:
what format is this and how might I parse it into something more intuitive and easier to read?
is there a robust, swiss-army-knife-esque way to convert dates without specifying input format?
Timezones necessarily make this more complex, so let's ignore them...
As #SteJ remarked, what you get is (close to) the time in seconds since 1st January 1970. Here's a Wikipedia article how that's normally used. Oddly, the string you get seems to have a timezone (-0500, EST in North America) attached. Makes no sense if it's properly UNIX time (which is always in UTC), but we'll pass on that...
Assuming you can get it reduced to a number (sans timezone) the conversion into something sensible in Python is really straight-forward (note the reduction in precision; your original number is the number of milliseconds since the epoch, rather than the standard number of seconds from the epoch):
from datetime import datetime
time_stamp = 1438318800
time_stamp_dt = datetime.fromtimestamp(time_stamp)
You can then get time_stamp_dt into any format you think best using strftime, e.g., time_stamp_dt.strftime('%m/%d/%Y'), which pretty much gives you what you started with.
Now, assuming that the format of the string you provided is fairly regular, we can extract the relevant time quite simply like this:
s = '/Date(1438318800000-0500)/'
time_stamp = int(s[6:16])
I'm trying to parse the date and time from a bunch of filenames that have one of these formats:
prefix.YYYY-MM-DD.suffix
prefix.YYYY-MM-DD_HH:MM:SS.sufix
prefix.YYYY-MM-DD-SSSSS.sufix
The datetime formats for these three are:
prefix.%Y-%m-%d.suffix
prefix.%Y-%m-%d_%H:%M:%S.suffix
prefix.%Y-%m-%d-%?????.suffix
The first two are easy to parse with the datetime module but I'm having trouble figuring out how to parse the 5-digit seconds which range from 00000 to 82800 (86400 seconds per day).
If at all possible, I'd like to use the standard datetime module as this needs to be extremely portable.
My goal is to have a function that can ingest multiple datetime formats so I need to stay away from a one off parser if possible.
def myparser(filename, datetimeformat):
# do some stuff - maybe as easy as
datetimeobject = datetime.strptime(filename, datetimeformat)
return datetimeobject
Any thoughts on how best to do this would be greatly appreciated.
If for all of them you split off the date and parse that as a datetime.datetime then parse the time into a datetime.timedetla and add it to the first value you should get where you need to be.
I would like a simple way to find and reformat text of the format 'DD/MM/YYYY' into 'YYYY/MM/DD' to be compatible with MySQL TIMESTAMPs, in a list of text items that may or may not contain a date atall, under python. (I'm thinking RegEx?)
Basically i am looking for a way to inspect a list of items and correct any timestamp formats found.
Great thing about standards is that there are so many to choose from....
You can read the string into a datetime object and then output it back as a string using a different format. For e.g.
>>> from datetime import datetime
>>> datetime.strptime("31/12/2009", "%d/%m/%Y").strftime("%Y/%m/%d")
'2009/12/31'
Basically i am looking for a way to inspect a list of items and correct any timestamp formats found.
If the input format is inconsistent, can vary, then you are better off with dateutil.
>>> from dateutil.parser import parse
>>> parse("31/12/2009").strftime("%Y/%m/%d")
'2009/12/31'
Dateutil can handle a lot of input formats automatically. To operate on a list you can map the a wrapper over the parse function over the list and convert the values appropriately.
If you're using the MySQLdb (also known as "mysql-python") module, for any datetime or timestamp field you can provide a datetime type instead of a string. This is the type that is returned, also and is the preferred way to provide the value.
For Python 2.5 and above, you can do:
from datetime import datetime
value = datetime.strptime(somestring, "%d/%m/%Y")
For older versions of python, it's a bit more verbose, but not really a big issue.
import time
from datetime import datetime
timetuple = time.strptime(somestring, "%d/%m/%Y")
value = datetime(*timetuple[:6])
The various format-strings are taken directly from what's accepted by your C library. Look up man strptime on unix to find other acceptable format values. Not all of the time formats are portable, but most of the basic ones are.
Note datetime values can contain timezones. I do not believe MySQL knows exactly what to do with these, though. The datetimes I make above are usually considered as "naive" datetimes. If timezones are important, consider something like the pytz library.