Re: [R] subsetting matrix according to columns with character index
Try this: x V1 V2 V3 1 a1 c1 1 2 a1 c1 2 3 a2 c1 1 4 a1 c2 1 5 a1 c2 2 lis - split(x, list(x$V1, x$V2), drop = TRUE) do.call(rbind, unname(lis[sapply(lis, function(x)all(1:2 %in% x[,3]))])) On Wed, Aug 13, 2008 at 3:00 PM, Ralph S. [EMAIL PROTECTED] wrote: Hi, I have a long matrix of the following form which I would like to subset according to the third column: [x y z]: a1 c1 1 a1 c1 2 a2 c1 1 a1 c2 1 a1 c2 2 . . . The first two columns a characters ai and cj. I would like to keep all the rows where there are two entries for z, 1 and 2. That is, I want: a1 c1 1 a1 c1 2 a1 c2 1 a1 c2 2 . . . I try to use something like df[by(df,c(df$x,df$y),sum(z)==3),] but that only gives me one line of data per x y combination. Is there an easy way of coding to keep all rows for a and c combinations where z has entries both 1 and 2? Many thanks, Ralph _ LM_WLYIA_whichathlete_us __ 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. -- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40 S 49° 16' 22 O __ 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.
Re: [R] subsetting matrix according to columns with character index
I tried this - I get an empty set: 0 rows (or 0-length row.names) I guess this happens because the z variable takes only one value per row?? What works is: DFsub-DF[DF$z == 1 | DF$z == 2,] but then, I do not eliminate the entries where there is only one entry for z given an a and c combination. Any idea what to do? -Ralph Date: Wed, 13 Aug 2008 13:05:25 -0500 From: [EMAIL PROTECTED] Subject: RE: [R] subsetting matrix according to columns with character index To: [EMAIL PROTECTED] it must be a dataframe so, if it was DF, then, assuming i understand what you want then either of the following should work: DFsub-DF[DF$z == 1 DF$z == 2,] or DFsub-subset(DF, z == 1 z == 2 ) On Wed, Aug 13, 2008 at 2:00 PM, Ralph S. wrote: Hi, I have a long matrix of the following form which I would like to subset according to the third column: [x y z]: a1 c1 1 a1 c1 2 a2 c1 1 a1 c2 1 a1 c2 2 . . . The first two columns a characters ai and cj. I would like to keep all the rows where there are two entries for z, 1 and 2. That is, I want: a1 c1 1 a1 c1 2 a1 c2 1 a1 c2 2 . . . I try to use something like df[by(df,c(df$x,df$y),sum(z)==3),] but that only gives me one line of data per x y combination. Is there an easy way of coding to keep all rows for a and c combinations where z has entries both 1 and 2? Many thanks, Ralph _ LM_WLYIA_whichathlete_us __ 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]] __ 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.
Re: [R] subsetting matrix according to columns with character index
i don't think i understood what you were trying to do, atleast based on Henrique's solution which I haven't cut and pasted yet in order to understand. Did Henrique's solution do what you wanted ? On Wed, Aug 13, 2008 at 2:45 PM, Ralph S. wrote: I tried this - I get an empty set: 0 rows (or 0-length row.names) I guess this happens because the z variable takes only one value per row?? What works is: DFsub-DF[DF$z == 1 | DF$z == 2,] but then, I do not eliminate the entries where there is only one entry for z given an a and c combination. Any idea what to do? -Ralph Date: Wed, 13 Aug 2008 13:05:25 -0500 From: [EMAIL PROTECTED] Subject: RE: [R] subsetting matrix according to columns with character index To: [EMAIL PROTECTED] it must be a dataframe so, if it was DF, then, assuming i understand what you want then either of the following should work: DFsub-DF[DF$z == 1 DF$z == 2,] or DFsub-subset(DF, z == 1 z == 2 ) On Wed, Aug 13, 2008 at 2:00 PM, Ralph S. wrote: Hi, I have a long matrix of the following form which I would like to subset according to the third column: [x y z]: a1 c1 1 a1 c1 2 a2 c1 1 a1 c2 1 a1 c2 2 . . . The first two columns a characters ai and cj. I would like to keep all the rows where there are two entries for z, 1 and 2. That is, I want: a1 c1 1 a1 c1 2 a1 c2 1 a1 c2 2 . . . I try to use something like df[by(df,c(df$x,df$y),sum(z)==3),] but that only gives me one line of data per x y combination. Is there an easy way of coding to keep all rows for a and c combinations where z has entries both 1 and 2? Many thanks, Ralph _ LM_WLYIA_whichathlete_us __ 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. ___ Your PC, mobile phone, and online services work together like never before. See how Windows® fits your life http://clk.atdmt.com/MRT/go/108587394/direct/01/ [[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 and provide commented, minimal, self-contained, reproducible code.
Re: [R] subsetting matrix according to columns with character index
sorry ralph. i meant the OR instead of the AND so that was my bad
mistake. the subset function should also work with the OR.
i think i understand better what you want now also. the approach below
for doing what you want assumes that , if there are 2 rows associated
with the
values in the first 2 columns , then they will be 1 and 2. If they are
1,1 or 2,2, then it won't work. So, henrique's solution could be better
and more general.
Assume your dataframe is called DF.
tempres-split(DF$x,DF$y)
onlytwo-lapply(tempres, function(.df)
if (nrow(.df) == 2) {
return(.df) } else {
return(NULL) }
)
onlytwo-onlytwo[!sapply(onlytwo,is.null)
result-do.call(rbind,onlytwo)
On Wed, Aug 13, 2008 at 2:45 PM, Ralph S. wrote:
I tried this - I get an empty set:
0 rows (or 0-length row.names)
I guess this happens because the z variable takes only one value per
row??
What works is:
DFsub-DF[DF$z == 1 | DF$z == 2,]
but then, I do not eliminate the entries where there is only one entry
for z given an a and c combination.
Any idea what to do?
-Ralph
Date: Wed, 13 Aug 2008 13:05:25 -0500 From: [EMAIL PROTECTED]
Subject: RE: [R] subsetting matrix according to columns with character
index To: [EMAIL PROTECTED]
it must be a dataframe so, if it was DF, then, assuming i understand
what you want then either of the following should work:
DFsub-DF[DF$z == 1 DF$z == 2,]
or
DFsub-subset(DF, z == 1 z == 2 )
On Wed, Aug 13, 2008 at 2:00 PM, Ralph S. wrote:
Hi,
I have a long matrix of the following form which I would like to
subset according to the third column:
[x y z]:
a1 c1 1 a1 c1 2 a2 c1 1 a1 c2 1 a1 c2 2 . . .
The first two columns a characters ai and cj.
I would like to keep all the rows where there are two entries for z,
1 and 2.
That is, I want: a1 c1 1 a1 c1 2 a1 c2 1 a1 c2 2 . . .
I try to use something like df[by(df,c(df$x,df$y),sum(z)==3),] but
that only gives me one line of data per x y combination.
Is there an easy way of coding to keep all rows for a and c
combinations where z has entries both 1 and 2? Many thanks,
Ralph
_
LM_WLYIA_whichathlete_us
__ 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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before. See how Windows® fits your life
http://clk.atdmt.com/MRT/go/108587394/direct/01/
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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.
Re: [R] subsetting matrix according to columns with character index
Ralph: I looked at Henrique's solution and he does 2 things which make
it better than mine.
1) He splits based off the first two columns where I just split based on
the second. So, my split assumes that the same rows are next to each
other
which is an unnecessary assumption.
2) He actually checks to make sure that 1 and 2 are actually in the
third column of the resulting dataframes that split returns. I assumed
that , if a
dataframe was of length 2, then the latter would be true automatically.
So, even though mine worked for what you needed, in the spirit of
generality and minimal assumptions, it better to use Henrique's
solution. Also,
make sure you understand it because you can learn a lot from it. ( this
is also true of his solutions in general ).
On Wed, Aug 13, 2008 at 3:37 PM, Ralph S. wrote:
yes this work, very elegant thank you. I didn't get Henriques message in
my mailbox immediately for some reason -
-Ralph
___
Date: Wed, 13 Aug 2008 14:23:33 -0500
From: [EMAIL PROTECTED]
Subject: RE: [R] subsetting matrix according to columns with character
index
To: [EMAIL PROTECTED]
CC: r-help@r-project.org
sorry ralph. i meant the OR instead of the AND so that was my bad
mistake. the subset function should also work with the OR.
i think i understand better what you want now also. the approach below
for doing what you want assumes that , if there are 2 rows associated
with the
values in the first 2 columns , then they will be 1 and 2. If they are
1,1 or 2,2, then it won't work. So, henrique's solution could be better
and more general.
Assume your dataframe is called DF.
tempres-split(DF$x,DF$y)
onlytwo-lapply(tempres, function(.df)
if (nrow(.df) == 2) {
return(.df) } else {
return(NULL) }
)
onlytwo-onlytwo[!sapply(onlytwo,is.null)
result-do.call(rbind,onlytwo)
On Wed, Aug 13, 2008 at 2:45 PM, Ralph S. wrote:
I tried this - I get an empty set:
0 rows (or 0-length row.names)
I guess this happens because the z variable takes only one value per
row??
What works is:
DFsub-DF[DF$z == 1 | DF$z == 2,]
but then, I do not eliminate the entries where there is only one entry
for z given an a and c combination.
Any idea what to do?
-Ralph
Date: Wed, 13 Aug 2008 13:05:25 -0500 From: [EMAIL PROTECTED]
Subject: RE: [R] subsetting matrix according to columns with character
index To: [EMAIL PROTECTED]
it must be a dataframe so, if it was DF, then, assuming i understand
what you want then either of the following should work:
DFsub-DF[DF$z == 1 DF$z == 2,]
or
DFsub-subset(DF, z == 1 z == 2 )
On Wed, Aug 13, 2008 at 2:00 PM, Ralph S. wrote:
Hi,
I have a long matrix of the following form which I would like to
subset according to the third column:
[x y z]:
a1 c1 1 a1 c1 2 a2 c1 1 a1 c2 1 a1 c2 2 . . .
The first two columns a characters ai and cj.
I would like to keep all the rows where there are two entries for z,
1 and 2.
That is, I want: a1 c1 1 a1 c1 2 a1 c2 1 a1 c2 2 . . .
I try to use something like df[by(df,c(df$x,df$y),sum(z)==3),] but
that only gives me one line of data per x y combination.
Is there an easy way of coding to keep all rows for a and c
combinations where z has entries both 1 and 2? Many thanks,
Ralph
_
LM_WLYIA_whichathlete_us
__ 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.
___
Your PC, mobile phone, and online services work together like never
before. See how Windows® fits your life
http://clk.atdmt.com/MRT/go/108587394/direct/01/
___
Get more from your digital life. Find out how.
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