R help - May 2009 - Please help me subset this dataframe, thanks...

Dear R-helpers,

I have a dataframe called "trackpoints" with several columns including
a column called "time", eg:
> trackpoints
?? ? ? ?time
1 ? 12:00:00
2 ? 12:00:01
3 ? 12:00:02
.
.
.
298 12:04:57
299 12:04:58
300 12:04:59

I also have a dataframe called "data" that contains columns called
"ID", "start" and "stop", eg:
> data
??ID ? ?start ? ? stop
1 ?1 12:00:00 12:01:30
2 ?2 12:02:16 12:03:01
3 ?3 12:03:58 12:04:31

I wish to make a dataframe called "extracted" containing only the rows
in "trackpoints" with a value of "time" bounded by the times
in
data$start and data$stop and a?column called "ID" containing the value
from data$ID, eg:
> extracted
?? ? ? ?Time ID
1 ? 12:00:00 ?1
2 ? 12:00:01 ?1
3 ? 12:00:02 ?1
.
.
.
89 ?12:01:28 ?1
90 ?12:01:29 ?1
91 ?12:01:30 ?1

I have the vague notion that I might have to loop this, but I think it
would be cleaner to use logical subscripts, if possible.
I'd appreciate any help you might be able to provide.

Thanks! Mark Na

Hi Mark.
Have a look at the commands:
merge
and
cbind

I believe they may hold the key.

I hope this helps :-)
Tal







On Mon, May 4, 2009 at 5:38 AM, Mark Na <mtb954@gmail.com> wrote:
> Dear R-helpers,
>
> I have a dataframe called "trackpoints" with several columns
including
> a column called "time", eg:
>
> > trackpoints
>         time
> 1   12:00:00
> 2   12:00:01
> 3   12:00:02
> .
> .
> .
> 298 12:04:57
> 299 12:04:58
> 300 12:04:59
>
> I also have a dataframe called "data" that contains columns
called
> "ID", "start" and "stop", eg:
>
> > data
>   ID    start     stop
> 1  1 12:00:00 12:01:30
> 2  2 12:02:16 12:03:01
> 3  3 12:03:58 12:04:31
>
> I wish to make a dataframe called "extracted" containing only the
rows
> in "trackpoints" with a value of "time" bounded by the
times in
> data$start and data$stop and a column called "ID" containing the
value
> from data$ID, eg:
>
> > extracted
>         Time ID
> 1   12:00:00  1
> 2   12:00:01  1
> 3   12:00:02  1
> .
> .
> .
> 89  12:01:28  1
> 90  12:01:29  1
> 91  12:01:30  1
>
> I have the vague notion that I might have to loop this, but I think it
> would be cleaner to use logical subscripts, if possible.
> I'd appreciate any help you might be able to provide.
>
> Thanks! Mark Na
>
> ______________________________________________
> R-help@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.
>


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