R help - Dec 2011 - How to extract an interval of "hour:minute" type

Hi, 

I 'd like to know how to extract an interval of "hour:minute" type
from a
column of POSIXlt POSIXct type. 
For instance: 

my_data.csv: 

4352;2011-09-02 21:30:00;3242; 
4352;2011-09-02 21:31:00;3315; 
4352;2011-09-02 21:32:00;4241; 
4352;2011-09-02 21:33:00;5394; 
... 
4352;2011-09-02 01:02:00;67; 
4352;2011-09-02 01:03:00;67; 
4352;2011-09-02 01:04:00;67; 
.... 

I loaded my_data.csv into a data.frame. 

I 'd like to select rows where times T satisfies 21:30:00<= T
<=22:30:00. I
do not worry about the date. I just need  the time to select the interval 

Thanks for your help

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Here is one way:
> x <- read.table(text = "4352;2011-09-02 21:30:00;3242;
+ 4352;2011-09-02 21:31:00;3315;
+ 4352;2011-09-02 21:32:00;4241;
+ 4352;2011-09-02 21:33:00;5394;", sep = ';', as.is =
TRUE)
> # create a 'character' of just the time.  If the data is of
> # the format above, 'substring' can be used
> x$time <- substring(x$V2, 12, 16)
> subset(x, time >= '21:31' & time <= '21:32')
    V1                  V2   V3 V4  time
2 4352 2011-09-02 21:31:00 3315 NA 21:31
3 4352 2011-09-02 21:32:00 4241 NA 21:32
>

On Tue, Dec 27, 2011 at 9:02 AM, ikuzar <razuki at hotmail.fr>
wrote:
> Hi,
>
> I 'd like to know how to extract an interval of "hour:minute"
type from a
> column of POSIXlt POSIXct type.
> For instance:
>
> my_data.csv:
>
> 4352;2011-09-02 21:30:00;3242;
> 4352;2011-09-02 21:31:00;3315;
> 4352;2011-09-02 21:32:00;4241;
> 4352;2011-09-02 21:33:00;5394;
> ...
> 4352;2011-09-02 01:02:00;67;
> 4352;2011-09-02 01:03:00;67;
> 4352;2011-09-02 01:04:00;67;
> ....
>
> I loaded my_data.csv into a data.frame.
>
> I 'd like to select rows where times T satisfies 21:30:00<= T
<=22:30:00. I
> do not worry about the date. I just need ?the time to select the interval
>
> Thanks for your help
>
> --
> View this message in context:
http://r.789695.n4.nabble.com/How-to-extract-an-interval-of-hour-minute-type-tp4237144p4237144.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
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> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.


-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.