What's the difference between `time& and numpy to convert a

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1

Hi, Dear all:
  I have a bunch of timestamp data. I need to pass them from python to kdb+. But I’m confused why the data conversion does not match each other.

  For example, the value of timestamp data is 12477000, the conversion in kdb+ is right, such as:

    q)`time$12477000

    03:27:57.000

  

  But the conversion in python(I use numpy and time to do the work) is not right:

    import numpy

    import time

    timeStamp_time = 12477000

    timeArray = time.gmtime(timeStamp_time)

    otherStyleTime = time.strftime(“%H:%M:%S”, timeArray)

    print(otherStyleTime)

  output is: 09:50:00

  Can somebody have any suggestion? Thanks so much!

Zheng

 

2

In time module, the output of time.strftime is:
    time.struct_time(tm_year=1970, tm_mon=5, tm_mday=25, tm_hour=09, tm_min=50, tm_sec=0, tm_wday=0, tm_yday=145, tm_isdst=0)

So, the key is how to let it know just hour:min:sec is required, year-month-day can be discarded.

3

Hi Zheng,

In kdb time is the number of milliseconds since midnight, in python time.gmtime uses the number of seconds since 1970.

Abdul

4

Yes, you’re right. I noticed it. But how can I let python time.gmtime convert since midnight or other cheat/magic method?

5

You can just divide by 1000

>>> import datetime                                                                                                                                           

>>> datetime.datetime.fromtimestamp(12477000/1000).strftime(“%H:%M:%S.%f”)                                                                                    

‘03:27:57.000000’ 

From: personal-kdbplus@googlegroups.com <personal-kdbplus@googlegroups.com> on behalf of hzadonis@gmail.com <hzadonis@gmail.com>
Sent: 04 June 2018 10:15:44
To: Kdb+ Personal Developers
Subject: [personal kdb+] Re: What’s the difference between `time& and numpy to convert a timestamp
 

Yes, you’re right. I noticed it. But how can I let python time.gmtime convert since midnight or other cheat/magic method?

6

Hi, Abdul:
  Yes, it works, thank you so much!

   How silly I am, I used to think it should be divided by 3600 yesterday. 

Thanks!

Zheng