R help - Mar 2010 - Creating dataframe of all possible variable combinations

Hello,

I need to create a dataframe containing all possible combinations of three
variables: SITE (101,102,103,104), WDAY (MON,TUE,WED,THR,FRI), and TOD (MORN,
AFTN). There should be a total of 40 unique combinations in my dataframe. I used
expand.grid() successfully(?) to create my dataframe, but then when I went to
order it by SITE, the resultant dataframe only contained four rows, one for each
site. There must be something about this function that I don't understand.
Any advice would be appreciated.

Thank you,

Mike

Hello,

I need to create a dataframe containing all possible combinations of 
three variables: SITE (101,102,103,104), WDAY (MON,TUE,WED,THR,FRI),
and TOD (MORN, AFTN). There should be a total of 40 unique combinations
in my dataframe. I used expand.grid() successfully(?) to create my 
dataframe, but then when I went to order it by SITE, the resultant 
dataframe only contained four rows, one for each site. There must 
be something about this function that I don't understand. Any advice
would be appreciated. 

Thank you,

Mike

Hi Mike,

Try this:

SITE <- c(101,102,103,104)
WDAY <-
c('MON','TUE','WED','THR','FRI')
TOD <- c('MORN', 'AFTN')
out <- expand.grid(SITE, WDAY, TOD)
out

HTH,
Jorge


On Thu, Mar 25, 2010 at 4:21 PM, Hosack, Michael <> wrote:
> Hello,
>
> I need to create a dataframe containing all possible combinations of three
> variables: SITE (101,102,103,104), WDAY (MON,TUE,WED,THR,FRI), and TOD
> (MORN, AFTN). There should be a total of 40 unique combinations in my
> dataframe. I used expand.grid() successfully(?) to create my dataframe, but
> then when I went to order it by SITE, the resultant dataframe only
contained
> four rows, one for each site. There must be something about this function
> that I don't understand. Any advice would be appreciated.
>
> Thank you,
>
> Mike
>
> ______________________________________________
> 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.
>
	[[alternative HTML version deleted]]

Hi Mike,

the following works for me:

SITE <- ordered(c(101,102,103,104))
WDAY <- 
ordered(c("MON","TUE","WED","THR","FRI"),levels=c("MON","TUE","WED","THR","FRI"))
TOD <-
ordered(c("MORN","AFTN"),levels=c("MORN","AFTN"))

foo <- expand.grid(SITE=SITE,WDAY=WDAY,TOD=TOD)
foo[order(foo$SITE),]

If this doesn't solve your problem, perhaps you could give us a minimal 
code snippet that demonstrates what exactly you are doing without 
getting what you are looking for?

Bye,
Stephan


Hosack, Michael schrieb:
> Hello,
> 
> I need to create a dataframe containing all possible combinations of
> three variables: SITE (101,102,103,104), WDAY (MON,TUE,WED,THR,FRI),
> and TOD (MORN, AFTN). There should be a total of 40 unique
> combinations in my dataframe. I used expand.grid() successfully(?) to
> create my dataframe, but then when I went to order it by SITE, the
> resultant dataframe only contained four rows, one for each site.
> There must be something about this function that I don't understand.
> Any advice would be appreciated.
> 
> Thank you,
> 
> Mike
> 
> ______________________________________________ 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.
>

Hello,

Hosack, Michael wrote:
> Hello,
> 
> I need to create a dataframe containing all possible combinations of
> three variables: SITE (101,102,103,104), WDAY (MON,TUE,WED,THR,FRI),
> and TOD (MORN, AFTN). There should be a total of 40 unique
> combinations in my dataframe. I used expand.grid() successfully(?) to
> create my dataframe, but then when I went to order it by SITE, the
> resultant dataframe only contained four rows, one for each site.
> There must be something about this function that I don't understand.
> Any advice would be appreciated.
I don't know what you see, since you don't provide reproducible code.  I
cannot reproduce what you saw.

tmp <- expand.grid(site = c(101,102,103,104),
                    wday =
c("MON","TUE","WED","THR","FRI"),
                    tod  = c ("MORN", "AFTN"))

tmp[order(tmp$site),]