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From | Neophytos Stylianou <neophytos.stylianou@postgrad.manchester.ac.uk> |
To | "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |
Subject | RE: st: Coverting variable to date and time |
Date | Fri, 24 May 2013 11:34:12 +0000 |
Thanks, I found out that the data source uses the atomic clock time measurement therefore %tc would be fine. Thanks Nick for the ampm command. If I only have time as string variable is there a way of changing it to numeric? For date you follow this command: gen datevar=date(mydatevar, "YMD") format date %d but for time only? Variable string 08:54:22 Neo -----Original Message----- From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox Sent: 24 May 2013 12:02 To: statalist@hsphsun2.harvard.edu Subject: Re: st: Coverting variable to date and time The difference between %tc and %tC is documented. If it's not clear to you, then perhaps Google "leap seconds" or go beyond the help and look at the manual. Your second -replace- won't work even in principle, and neither will work in practice. gen ampm = cond(hh(datetime) < 12, "am", "pm") might be one way of doing what I think you want. Nick njcoxstata@gmail.com On 24 May 2013 11:45, Neophytos Stylianou <neophytos.stylianou@postgrad.manchester.ac.uk> wrote: > Nick I have some more questions about time and date. > > I have read through the help file but it is not clear to me what is > the difference of %tc and %tC > > I have converted my data to YMDhms and it works > > Just for my practise I have also split the variable and converted the > two splits into date and time variable form strings > > I have entries for the same date but for morning as well as afternoon. > > How will I separate them in AM and PM? > > Is it something like: > Gen time2= AM if time1 >=00:00:00 & time1<=12:00:00 Replace time2=PM > if time1>12:00:00 &time1<00:00:00 > > Thnaks > Neo > > -----Original Message----- > From: owner-statalist@hsphsun2.harvard.edu > [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Nick Cox > Sent: 24 May 2013 11:00 > To: statalist@hsphsun2.harvard.edu > Subject: Re: st: Coverting variable to date and time > > That is no problem: it is in many ways the easiest and best way to import dates and/or times into Stata. > > From your example, the -split- command is sufficient to split your variable into date and time strings: its default is to parse on spaces. See -help split-. However, that is a red herring here. > > Stata has a rich variety of date and time functions making anything that you want. See -help dates- for a full introduction. What is below shows how to start. The help I have referenced shows how to go further. > > . set obs 1 > obs was 0, now 1 > > . gen double datetime = clock("2005-02-19 09:38:00.000", "YMD hms") > > . format datetime %tc > > . l > > +--------------------+ > | datetime | > |--------------------| > 1. | 19feb2005 09:38:00 | > +--------------------+ > > Nick > njcoxstata@gmail.com > > > On 24 May 2013 10:35, Neophytos Stylianou <neophytos.stylianou@postgrad.manchester.ac.uk> wrote: >> Hello, >> >> I am using Stata 12.1 and I have a variable containing date and time. >> >> The problem is that it is a string variable and it contains both date and time within it. >> >> I want to split them into date variable and time variable but also have the opportunity to have a date time combined variable. >> >> Example of what the variable contains : >> >> 2005-02-19 09:38:00.000 >> 2005-02-19 09:46:00.000 >> >> I want a variable of date i.e 19/02/2005 and time 09:38:00 >> >> I would do it manually if it was a small number of records but there >> are more than 1.3million rows >> >> I know that I can combine the date and time variables which will be >> created using gen double datetime = date*24*60*60*1000 + time format >> datetime %tcNN/DD/CCYY_HH:MM:SS >> > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/statalist-faq/ > * http://www.ats.ucla.edu/stat/stata/ > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/statalist-faq/ > * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/