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.
Related
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
I have a python script that generates a datetime string using this line of code:
data['timestamp'] = datetime.isoformat(datetime.utcnow())
That generates something like the following:
2017-05-24T04:08:09.530033
How do I convert that to "MYSQL insertable" datetime format in a clean way?
Thanks!
Try to use MySQL's STR_TO_DATE() function to parse the string that you're attempting to insert.
I hope this may help you
You can specify any type of format like this depending on the one you `ve set in mysql
data['timestamp'] =pd.to_datetime(data['timestamp'] , format='%d%b%Y:%H:%M:%S.%f')
First off, it looks like you ran from datetime import * rather than import datetime. That's tempting because it lets you type less when you want to refer to parts of the module, but it can get you into name collision issues later. An alternative with less typing is something like import datetime as dt, that way later you can just use dt.datetime. This will make your code cleaner.
MySQL accepts several date formats, which can be read about in detail here. In particular:
The DATETIME type is used for values that contain both date and time
parts. MySQL retrieves and displays DATETIME values in YYYY-MM-DD HH:MM:SS format.
ISO8601 numbers look just like that! 2017-05-24T04:19:32
So if the only difference is the "T" in the middle instead of a space, just run something like this, assuming you don't change your import statements.
timestamp = str(datetime.isoformat(datetime.utcnow()))
timestamp = timestamp.replace("T", " ")
data['timestamp'] = timestamp
To keep track of my when my files were backed up I want to have the filename of the backups as the datetime of when they were backed up. This will eventually be sorted and retrieved and sorted using python to allow me to get the most recent file based on the datetime filename.
The problem is, the automatic format of date time cant be saved like this:
2007-12-31 22:29:59
It can for example be saved like this:
2007-12-31 22-29-59
What is the best way to format the datetime so that I can easily sort by datetime on the name, and for bonus points, what is the python to show the datetime in that way.
You should have a look the documentation of the python time module: http://docs.python.org/2/library/time.html#module-time
If you go to the strftime() function, you will see that it accepts a string as input, which describes the format of the string you want to get as the return value.
Example (with hyphens between each date/time token):
>>> s = time.strftime('%Y-%m-%d-%H-%M-%S')
>>> print s
2012-12-08-14-55-44
The documentation contains a complete table of directives you can use to get different tokens.
What is the best way to format the datetime so that I can easily sort by datetime?
If you want to sort files according to datetimes names, you can consider that a biggest-to-lowest time specifier representation of a datetime (e.g.: YYYYMMDDhhmmss) preserves the same chronological and lexicographical order.
I'm trying to convert a parameter of type string to a date time. I'm using the dateUtil library
from dateutil import parser
myDate_string="2001/9/1 12:00:03"
dt = parser.parse(myDate_string,dayfirst=True)
print dt
every time i run this i get
2001-09-01 12:00:03
regardless of whether i have dayfirst set as true or Year first set as false. Ideally I just want to have a date in the format DD-MM-YYYY HH:MM:SS. I don't want anything fancy. I am willing to use the datetime library but this doesn't seem to work at all for me. Can anyone give simple expamples of how to convert strings to date time with an explicit format, I'm a noob, so the most basic examples are all i require. I'm using Python 2.7
The problem you're having is that any arguments you pass to parser.parse only affect how the string is parsed, not how the subsequent object is printed.
parser.parse returns a datetime object - when you print it it will just use datetime's default __str__ method. If you replace your last line with
print dt.strftime("%d-%m-%Y %H:%M:%S")
it will work as you expect.
The standard lib (built-in) datetime lib can do this easily.
from datetime import datetime
my_date_string = "2001/9/1 12:00:03"
d = datetime.strptime(my_date_string, "%Y/%m/%d %H:%M:%S")
print d.strftime("%d-%m-%Y %H:%M:%S")
How to set default datetime format in python because i have multiple tuples to send via template on client side. This is not good approach to set each object's value to specified format. I want to set a datetime format on server side and these converted values will be shown to client. I tried
datetime.strftime("%Y-%m-%d %X")
but it is giving error.
strftime is a method of datetime objects - it doesn't set a default representation, which seems to be what you suggest. For example, you might call it like this:
>>> import datetime
>>> now = datetime.datetime.now()
>>> now.strftime("%Y-%m-%d %X")
'2011-03-17 10:14:12'
If you need to do this a lot, it would be worth creating a method that wraps this conversion of a datetime to a string. The documentation for the datetime module can be found here.
I'm not sure I understand your issue, but this might help
http://docs.djangoproject.com/en/dev/ref/settings/
there is a datetime format section, this sets datetime format globally.