R help - Feb 2009 - How to create sequence of constant time interval

Dear R-Experts, 

seek your help.

There are two parts I want to deal with.
1) 
I want to create a time interval of say, 30 minutes starting from
"00:00:00"
hrs
Thus at the end, I want to create sequence:
00:00:00
00:30:00
01:00:00 
01:30:00
..
..
How to do so ?
Later, I want to change the time-increment value in a variable and changing
the value of this variable, I would like to create new sequence with that
time increment. How to use "seq()" correctly?

2)
I have a date stored in one variable. Say "2009-01-01"
How can I combine this date with each time interval in the first part? Will
concatenate work?
so at the end, I would like to have:

2009-01-01 00:00:00
2009-01-01 00:30:00
2009-01-01 01:00:00
2009-01-01 01:30:00
...
...

Thank you in advance.






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Try this (and see R News 4/1 for more).
> library(chron)
> tt <- times(0:47/48)
> tt
 [1] 00:00:00 00:30:00 01:00:00 01:30:00 02:00:00 02:30:00 03:00:00
03:30:00 04:00:00 04:30:00 05:00:00 05:30:00 06:00:00 06:30:00
07:00:00 07:30:00
[17] 08:00:00 08:30:00 09:00:00 09:30:00 10:00:00 10:30:00 11:00:00
11:30:00 12:00:00 12:30:00 13:00:00 13:30:00 14:00:00 14:30:00
15:00:00 15:30:00
[33] 16:00:00 16:30:00 17:00:00 17:30:00 18:00:00 18:30:00 19:00:00
19:30:00 20:00:00 20:30:00 21:00:00 21:30:00 22:00:00 22:30:00
23:00:00 23:30:00
> chron(rep("1/1/09", length = length(tt)), tt)
 [1] (01/01/09 00:00:00) (01/01/09 00:30:00) (01/01/09 01:00:00)
(01/01/09 01:30:00) (01/01/09 02:00:00) (01/01/09 02:30:00) (01/01/09
03:00:00)
 [8] (01/01/09 03:30:00) (01/01/09 04:00:00) (01/01/09 04:30:00)
(01/01/09 05:00:00) (01/01/09 05:30:00) (01/01/09 06:00:00) (01/01/09
06:30:00)
[15] (01/01/09 07:00:00) (01/01/09 07:30:00) (01/01/09 08:00:00)
(01/01/09 08:30:00) (01/01/09 09:00:00) (01/01/09 09:30:00) (01/01/09
10:00:00)
[22] (01/01/09 10:30:00) (01/01/09 11:00:00) (01/01/09 11:30:00)
(01/01/09 12:00:00) (01/01/09 12:30:00) (01/01/09 13:00:00) (01/01/09
13:30:00)
[29] (01/01/09 14:00:00) (01/01/09 14:30:00) (01/01/09 15:00:00)
(01/01/09 15:30:00) (01/01/09 16:00:00) (01/01/09 16:30:00) (01/01/09
17:00:00)
[36] (01/01/09 17:30:00) (01/01/09 18:00:00) (01/01/09 18:30:00)
(01/01/09 19:00:00) (01/01/09 19:30:00) (01/01/09 20:00:00) (01/01/09
20:30:00)
[43] (01/01/09 21:00:00) (01/01/09 21:30:00) (01/01/09 22:00:00)
(01/01/09 22:30:00) (01/01/09 23:00:00) (01/01/09 23:30:00)


On Mon, Feb 16, 2009 at 5:00 AM, Suresh_FSFM <suresh.ghalsasi at
gmail.com> wrote:
>
> Dear R-Experts,
>
> seek your help.
>
> There are two parts I want to deal with.
> 1)
> I want to create a time interval of say, 30 minutes starting from
"00:00:00"
> hrs
> Thus at the end, I want to create sequence:
> 00:00:00
> 00:30:00
> 01:00:00
> 01:30:00
> ..
> ..
> How to do so ?
> Later, I want to change the time-increment value in a variable and changing
> the value of this variable, I would like to create new sequence with that
> time increment. How to use "seq()" correctly?
>
> 2)
> I have a date stored in one variable. Say "2009-01-01"
> How can I combine this date with each time interval in the first part? Will
> concatenate work?
> so at the end, I would like to have:
>
> 2009-01-01 00:00:00
> 2009-01-01 00:30:00
> 2009-01-01 01:00:00
> 2009-01-01 01:30:00
> ...
> ...
>
> Thank you in advance.
>
>
>
>
>
>
> --
> View this message in context:
http://www.nabble.com/How-to-create-sequence-of-constant-time-interval-tp22034441p22034441.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Thank you very much for the precise response.


Regards,
Suresh


Suresh_FSFM wrote:
> 
> Dear R-Experts, 
> 
> seek your help.
> 
> There are two parts I want to deal with.
> 1) 
> I want to create a time interval of say, 30 minutes starting from
> "00:00:00" hrs
> Thus at the end, I want to create sequence:
> 00:00:00
> 00:30:00
> 01:00:00 
> 01:30:00
> ..
> ..
> How to do so ?
> Later, I want to change the time-increment value in a variable and
> changing the value of this variable, I would like to create new sequence
> with that time increment. How to use "seq()" correctly?
> 
> 2)
> I have a date stored in one variable. Say "2009-01-01"
> How can I combine this date with each time interval in the first part?
> Will concatenate work?
> so at the end, I would like to have:
> 
> 2009-01-01 00:00:00
> 2009-01-01 00:30:00
> 2009-01-01 01:00:00
> 2009-01-01 01:30:00
> ...
> ...
> 
> Thank you in advance.
> 
> 
> 
> 
> 
> 
> 
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View this message in context:
http://www.nabble.com/How-to-create-sequence-of-constant-time-interval-tp22034441p22035427.html
Sent from the R help mailing list archive at Nabble.com.

Something like the following might give a few ideas:
> start.date <- '2009-01-01'
> start.time <- '00:00:00'
> interval <- 30
>
> increment.mins <- interval * 60
> x <- paste(start.date, start.time)
>
> for(i in 1:20) {
+   print(strptime(x, "%Y-%m-%d %H:%M:%S")  + i*increment.mins)
+ }
[1] "2009-01-01 00:30:00 GMT"
[1] "2009-01-01 01:00:00 GMT"
[1] "2009-01-01 01:30:00 GMT"
[1] "2009-01-01 02:00:00 GMT"
[1] "2009-01-01 02:30:00 GMT"
[1] "2009-01-01 03:00:00 GMT"
[1] "2009-01-01 03:30:00 GMT"
[1] "2009-01-01 04:00:00 GMT"
[1] "2009-01-01 04:30:00 GMT"
[1] "2009-01-01 05:00:00 GMT"
[1] "2009-01-01 05:30:00 GMT"
[1] "2009-01-01 06:00:00 GMT"
[1] "2009-01-01 06:30:00 GMT"
[1] "2009-01-01 07:00:00 GMT"
[1] "2009-01-01 07:30:00 GMT"
[1] "2009-01-01 08:00:00 GMT"
[1] "2009-01-01 08:30:00 GMT"
[1] "2009-01-01 09:00:00 GMT"
[1] "2009-01-01 09:30:00 GMT"
[1] "2009-01-01 10:00:00 GMT"
>
On 16 Feb, 10:00, Suresh_FSFM <suresh.ghals... at gmail.com>
wrote:
> Dear R-Experts,
>
> seek your help.
>
> There are two parts I want to deal with.
> 1)
> I want to create a time interval of say, 30 minutes starting from
"00:00:00"
> hrs
> Thus at the end, I want to create sequence:
> 00:00:00
> 00:30:00
> 01:00:00
> 01:30:00
> ..
> ..
> How to do so ?
> Later, I want to change the time-increment value in a variable and changing
> the value of this variable, I would like to create new sequence with that
> time increment. How to use "seq()" correctly?
>
> 2)
> I have a date stored in one variable. Say "2009-01-01"
> How can I combine this date with each time interval in the first part? Will
> concatenate work?
> so at the end, I would like to have:
>
> 2009-01-01 00:00:00
> 2009-01-01 00:30:00
> 2009-01-01 01:00:00
> 2009-01-01 01:30:00
> ...
> ...
>
> Thank you in advance.
>
> --
> View this message in
context:http://www.nabble.com/How-to-create-sequence-of-constant-time-interva...
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-h... at r-project.org mailing
listhttps://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

ahh, didn't see Gabor's solution, that works much better :-)

On 16 Feb, 10:00, Suresh_FSFM <suresh.ghals... at gmail.com>
wrote:
> Dear R-Experts,
>
> seek your help.
>
> There are two parts I want to deal with.
> 1)
> I want to create a time interval of say, 30 minutes starting from
"00:00:00"
> hrs
> Thus at the end, I want to create sequence:
> 00:00:00
> 00:30:00
> 01:00:00
> 01:30:00
> ..
> ..
> How to do so ?
> Later, I want to change the time-increment value in a variable and changing
> the value of this variable, I would like to create new sequence with that
> time increment. How to use "seq()" correctly?
>
> 2)
> I have a date stored in one variable. Say "2009-01-01"
> How can I combine this date with each time interval in the first part? Will
> concatenate work?
> so at the end, I would like to have:
>
> 2009-01-01 00:00:00
> 2009-01-01 00:30:00
> 2009-01-01 01:00:00
> 2009-01-01 01:30:00
> ...
> ...
>
> Thank you in advance.
>
> --
> View this message in
context:http://www.nabble.com/How-to-create-sequence-of-constant-time-interva...
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-h... at r-project.org mailing
listhttps://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

For version 2.3-30 of chron which just appeared on CRAN this can
be simplified to:

library(chron)
tt <- times(0:47/48)
tt
chron("1/1/09", tt) # no rep needed

On Mon, Feb 16, 2009 at 6:04 AM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> Try this (and see R News 4/1 for more).
>
>> library(chron)
>> tt <- times(0:47/48)
>> tt
>  [1] 00:00:00 00:30:00 01:00:00 01:30:00 02:00:00 02:30:00 03:00:00
> 03:30:00 04:00:00 04:30:00 05:00:00 05:30:00 06:00:00 06:30:00
> 07:00:00 07:30:00
> [17] 08:00:00 08:30:00 09:00:00 09:30:00 10:00:00 10:30:00 11:00:00
> 11:30:00 12:00:00 12:30:00 13:00:00 13:30:00 14:00:00 14:30:00
> 15:00:00 15:30:00
> [33] 16:00:00 16:30:00 17:00:00 17:30:00 18:00:00 18:30:00 19:00:00
> 19:30:00 20:00:00 20:30:00 21:00:00 21:30:00 22:00:00 22:30:00
> 23:00:00 23:30:00
>
>> chron(rep("1/1/09", length = length(tt)), tt)
>  [1] (01/01/09 00:00:00) (01/01/09 00:30:00) (01/01/09 01:00:00)
> (01/01/09 01:30:00) (01/01/09 02:00:00) (01/01/09 02:30:00) (01/01/09
> 03:00:00)
>  [8] (01/01/09 03:30:00) (01/01/09 04:00:00) (01/01/09 04:30:00)
> (01/01/09 05:00:00) (01/01/09 05:30:00) (01/01/09 06:00:00) (01/01/09
> 06:30:00)
> [15] (01/01/09 07:00:00) (01/01/09 07:30:00) (01/01/09 08:00:00)
> (01/01/09 08:30:00) (01/01/09 09:00:00) (01/01/09 09:30:00) (01/01/09
> 10:00:00)
> [22] (01/01/09 10:30:00) (01/01/09 11:00:00) (01/01/09 11:30:00)
> (01/01/09 12:00:00) (01/01/09 12:30:00) (01/01/09 13:00:00) (01/01/09
> 13:30:00)
> [29] (01/01/09 14:00:00) (01/01/09 14:30:00) (01/01/09 15:00:00)
> (01/01/09 15:30:00) (01/01/09 16:00:00) (01/01/09 16:30:00) (01/01/09
> 17:00:00)
> [36] (01/01/09 17:30:00) (01/01/09 18:00:00) (01/01/09 18:30:00)
> (01/01/09 19:00:00) (01/01/09 19:30:00) (01/01/09 20:00:00) (01/01/09
> 20:30:00)
> [43] (01/01/09 21:00:00) (01/01/09 21:30:00) (01/01/09 22:00:00)
> (01/01/09 22:30:00) (01/01/09 23:00:00) (01/01/09 23:30:00)
>
>
> On Mon, Feb 16, 2009 at 5:00 AM, Suresh_FSFM <suresh.ghalsasi at
gmail.com> wrote:
>>
>> Dear R-Experts,
>>
>> seek your help.
>>
>> There are two parts I want to deal with.
>> 1)
>> I want to create a time interval of say, 30 minutes starting from
"00:00:00"
>> hrs
>> Thus at the end, I want to create sequence:
>> 00:00:00
>> 00:30:00
>> 01:00:00
>> 01:30:00
>> ..
>> ..
>> How to do so ?
>> Later, I want to change the time-increment value in a variable and
changing
>> the value of this variable, I would like to create new sequence with
that
>> time increment. How to use "seq()" correctly?
>>
>> 2)
>> I have a date stored in one variable. Say "2009-01-01"
>> How can I combine this date with each time interval in the first part?
Will
>> concatenate work?
>> so at the end, I would like to have:
>>
>> 2009-01-01 00:00:00
>> 2009-01-01 00:30:00
>> 2009-01-01 01:00:00
>> 2009-01-01 01:30:00
>> ...
>> ...
>>
>> Thank you in advance.
>>
>>
>>
>>
>>
>>
>> --
>> View this message in context:
http://www.nabble.com/How-to-create-sequence-of-constant-time-interval-tp22034441p22034441.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>