R help - Jun 2009 - How to select partially (not completely) unique rows?

Dear R-helpers,

I know how to use unique to select unique rows, e.g.

unique.rows<-unique(dataframe)

but I would like to select those rows that are unique only only TWO of my
dataframe's columns (so, two rows with the same value on these two columns
would not be kept, even if they had different values in other columns).

For example, I have a dataframe with 10 columns, two of which are LATITUDE
and LONGITUDE. I wish to keep only one row per unique combination of these
two columns, so I've tried:

unique.latlong<-extracted[unique(paste(extracted$latitude,extracted$longitude)),]

but this is returning a dataframe of missing values (NAs).

Could anyone point me in the right direction?

Thanks! Mark Na

	[[alternative HTML version deleted]]

Try this:

DF[!duplicated(DF[,c("lat","lon")]),]


On Mon, Jun 29, 2009 at 6:55 PM, Mark Na <mtb954@gmail.com> wrote:
> Dear R-helpers,
>
> I know how to use unique to select unique rows, e.g.
>
> unique.rows<-unique(dataframe)
>
> but I would like to select those rows that are unique only only TWO of my
> dataframe's columns (so, two rows with the same value on these two
columns
> would not be kept, even if they had different values in other columns).
>
> For example, I have a dataframe with 10 columns, two of which are LATITUDE
> and LONGITUDE. I wish to keep only one row per unique combination of these
> two columns, so I've tried:
>
>
>
unique.latlong<-extracted[unique(paste(extracted$latitude,extracted$longitude)),]
>
> but this is returning a dataframe of missing values (NAs).
>
> Could anyone point me in the right direction?
>
> Thanks! Mark Na
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> 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<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

	[[alternative HTML version deleted]]

Hi Mark,

If you convert the data.frame to a Spatial class (see the sp-package 
documentation) you can use the function zerodist to find spatial 
locations that are at the same locations.

cheers,
Paul

Mark Na wrote:
> Dear R-helpers,
>
> I know how to use unique to select unique rows, e.g.
>
> unique.rows<-unique(dataframe)
>
> but I would like to select those rows that are unique only only TWO of my
> dataframe's columns (so, two rows with the same value on these two
columns
> would not be kept, even if they had different values in other columns).
>
> For example, I have a dataframe with 10 columns, two of which are LATITUDE
> and LONGITUDE. I wish to keep only one row per unique combination of these
> two columns, so I've tried:
>
>
unique.latlong<-extracted[unique(paste(extracted$latitude,extracted$longitude)),]
>
> but this is returning a dataframe of missing values (NAs).
>
> Could anyone point me in the right direction?
>
> Thanks! Mark Na
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
>   

-- 
Drs. Paul Hiemstra
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
Heidelberglaan 2
P.O. Box 80.115
3508 TC Utrecht
Phone:  +3130 274 3113 Mon-Tue
Phone:  +3130 253 5773 Wed-Fri
http://intamap.geo.uu.nl/~paul