How can I parse a time string containing milliseco

Question

I am able to parse strings containing date/time with time.strptime

>>> import time
>>> time.strptime('30/03/09 16:31:32', '%d/%m/%y %H:%M:%S')
(2009, 3, 30, 16, 31, 32, 0, 89, -1)

How can I parse a time string that contains milliseconds?

>>> time.strptime('30/03/09 16:31:32.123', '%d/%m/%y %H:%M:%S')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.5/_strptime.py", line 333, in strptime
    data_string[found.end():])
ValueError: unconverted data remains: .123

Answer 1

DNS answer above is actually incorrect. The SO is asking about milliseconds but the answer is for microseconds. Unfortunately, Python`s doesn't have a directive for milliseconds, just microseconds (see doc), but you can workaround it by appending three zeros at the end of the string and parsing the string as microseconds, something like:

datetime.strptime(time_str + '000', '%d/%m/%y %H:%M:%S.%f')

where time_str is formatted like 30/03/09 16:31:32.123.

Hope this helps.

Answer 2

from python mailing lists: parsing millisecond thread. There is a function posted there that seems to get the job done, although as mentioned in the author's comments it is kind of a hack. It uses regular expressions to handle the exception that gets raised, and then does some calculations.

You could also try do the regular expressions and calculations up front, before passing it to strptime.

Answer 3

To give the code that nstehr's answer refers to (from its source):

def timeparse(t, format):
    """Parse a time string that might contain fractions of a second.

    Fractional seconds are supported using a fragile, miserable hack.
    Given a time string like '02:03:04.234234' and a format string of
    '%H:%M:%S', time.strptime() will raise a ValueError with this
    message: 'unconverted data remains: .234234'.  If %S is in the
    format string and the ValueError matches as above, a datetime
    object will be created from the part that matches and the
    microseconds in the time string.
    """
    try:
        return datetime.datetime(*time.strptime(t, format)[0:6]).time()
    except ValueError, msg:
        if "%S" in format:
            msg = str(msg)
            mat = re.match(r"unconverted data remains:"
                           " \.([0-9]{1,6})$", msg)
            if mat is not None:
                # fractional seconds are present - this is the style
                # used by datetime's isoformat() method
                frac = "." + mat.group(1)
                t = t[:-len(frac)]
                t = datetime.datetime(*time.strptime(t, format)[0:6])
                microsecond = int(float(frac)*1e6)
                return t.replace(microsecond=microsecond)
            else:
                mat = re.match(r"unconverted data remains:"
                               " \,([0-9]{3,3})$", msg)
                if mat is not None:
                    # fractional seconds are present - this is the style
                    # used by the logging module
                    frac = "." + mat.group(1)
                    t = t[:-len(frac)]
                    t = datetime.datetime(*time.strptime(t, format)[0:6])
                    microsecond = int(float(frac)*1e6)
                    return t.replace(microsecond=microsecond)

        raise

Answer 4

For python 2 i did this

print ( time.strftime("%H:%M:%S", time.localtime(time.time())) + "." + str(time.time()).split(".",1)[1])

it prints time "%H:%M:%S" , splits the time.time() to two substrings (before and after the .) xxxxxxx.xx and since .xx are my milliseconds i add the second substring to my "%H:%M:%S"

hope that makes sense :) Example output:

13:31:21.72 Blink 01

---

13:31:21.81 END OF BLINK 01

---

13:31:26.3 Blink 01

---

13:31:26.39 END OF BLINK 01

---

13:31:34.65 Starting Lane 01

---

Answer 5

I know this is an older question but I'm still using Python 2.4.3 and I needed to find a better way of converting the string of data to a datetime.

The solution if datetime doesn't support %f and without needing a try/except is:

    (dt, mSecs) = row[5].strip().split(".") 
    dt = datetime.datetime(*time.strptime(dt, "%Y-%m-%d %H:%M:%S")[0:6])
    mSeconds = datetime.timedelta(microseconds = int(mSecs))
    fullDateTime = dt + mSeconds 

This works for the input string "2010-10-06 09:42:52.266000"

Answer 6

Python 2.6 added a new strftime/strptime macro %f, which does microseconds. Not sure if this is documented anywhere. But if you're using 2.6 or 3.0, you can do this:

time.strptime('30/03/09 16:31:32.123', '%d/%m/%y %H:%M:%S.%f')

Edit: I never really work with the time module, so I didn't notice this at first, but it appears that time.struct_time doesn't actually store milliseconds/microseconds. You may be better off using datetime, like this:

>>> from datetime import datetime
>>> a = datetime.strptime('30/03/09 16:31:32.123', '%d/%m/%y %H:%M:%S.%f')
>>> a.microsecond
123000