Re: [R] sampling dataframe based upon number of record occurrences
I'm not sure I understand, but I think you have a large data frame with records
and you want to construct a sample of that data frame that includes no more
than 3 records for each IDbyYear combination? You say there are 5589 unique
combinations and your code uses a data frame called fitting_set. Assuming this
is the data frame you are describing, your code will select all of the lines
since fitting_set$IDbyYear[i] is always a vector of length 1.
We need a reproducible example. The best way for you to give us that would be
to copy the result of dput(head(fitting_set, 10)). It would look something like
this plus the 6 other columns you mention except that I've added dta - in
front of structure() to create a data frame:
dta - structure(list(IDbyYear = c(42.24, 42.24, 42.24, 42.24, 42.24,
42.24, 45.32, 45.32, 45.36, 45.4, 45.4), SiteID = structure(c(1L,
1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L), .Label = c(A-Airport,
A-Bark Corral East), class = factor), Year = c(2006L, 2006L,
2006L, 2006L, 2006L, 2006L, 2008L, 2008L, 2009L, 2010L, 2010L
)), .Names = c(IDbyYear, SiteID, Year), class = data.frame, row.names =
c(NA,
-11L))
Now create a list of data frames, one for each IDbyYear:
dta.list - split(dta, dta$IDbyYear)
Now a function that will select 3 rows or all of them if there are fewer:
smp - function(dframe) {
ind - seq_len(nrow(dframe))
dframe[sample(ind, ifelse(length(ind)2, 3, length(ind))),]
}
Now take the samples and combine them into a single data frame:
sample - do.call(rbind, lapply(dta.list, smp))
sample
-
David L Carlson
Department of Anthropology
Texas AM University
College Station, TX 77840-4352
-Original Message-
From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Curtis
Burkhalter
Sent: Tuesday, March 3, 2015 3:23 PM
To: r-help@r-project.org
Subject: [R] sampling dataframe based upon number of record occurrences
Hello everyone,
I'm having trouble performing a task that is probably very simple, but
can't seem to figure out how to get my code to work. What I want to do is
use the sample function to pick records within in a dataframe, but only if
a column attribute value is repeated more than 3 times. So if you look at
the data below I have created a unique attribute value that corresponds to
every site by year combination (i.e. IDxYear). So you can see that for the
site called A-Airport it was sampled 6 times in 2006, A-Bank Corral
East was sampled twice in 2008. So what I want to do is randomly select 3
records for A-Airport in 2006 for the existing 6 records, but for A-Bark
Corral East in 2008 I just want to leave these records as they currently
are.
I've used the following code to try and accomplish this, but like I said I
can't get it to work so I'm clearly doing something wrong. If you could
check out the code and provide any suggestions that would be great. It
should be noted that there are 5589 unique IDxYear combinations so that's
why that number is in the code. If any further clarification is needed also
let me know.
boom=data.frame()
for (i in 1:5589){
boom[i,]=ifelse(length(fitting_set$IDbyYear[i]3),fitting_set[sample(nrow(fitting_set),3),],fitting_set)
}
boom
*IDbyYear* *SiteID * *Year*
*6 other column attributes*
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
45.32 A-Bark Corral East2008
45.32 A-Bark Corral East2008
45.36 A-Bark Corral East2009
45.40 A-Bark Corral East2010
45.40 A-Bark Corral East 2010
Thanks
--
Curtis Burkhalter
https://sites.google.com/site/curtisburkhalter/
[[alternative HTML version deleted]]
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Re: [R] sampling dataframe based upon number of record occurrences
Here is an implementation with function named getSample. Some modification to
the data was made so that it can be read as a table.
fitting.set
IDbyYear SiteID Year
1 42.24 A-Airport 2006
2 42.24 A-Airport 2006
3 42.24 A-Airport 2006
4 42.24 A-Airport 2006
5 42.24 A-Airport 2006
6 42.24 A-Airport 2006
7 45.32 A-Bark.Corral.East 2008
8 45.32 A-Bark.Corral.East 2008
9 45.36 A-Bark.Corral.East 2009
1045.40 A-Bark.Corral.East 2010
1145.40 A-Bark.Corral.East 2010
getSample
function(x)
{
sites - unique(x$SiteID)
years - unique(x$Year)
result - data.frame()
x$ID - seq(1,nrow(x))
for (i in 1:length(sites))
{
for (j in 1:length(years))
{
if (nrow(x[as.character(x$SiteID)==as.character(sites[i])
x$Year==years[j],]) 3)
{
sampledID - sample(x[as.character(x$SiteID)==as.character(sites[i])
x$Year==years[j],]$ID,3,replace=FALSE)
for (k in 1:length(sampledID))
{
result - rbind(result,x[x$ID==sampledID[k],-4])
}
}
}
}
names(result) - c(IDbyYear,SiteID,Year)
rownames(result) - NULL
return(result)
}
getSample(fitting.set)
IDbyYearSiteID Year
142.24 A-Airport 2006
242.24 A-Airport 2006
342.24 A-Airport 2006
--
View this message in context:
http://r.789695.n4.nabble.com/sampling-dataframe-based-upon-number-of-record-occurrences-tp4704144p4704154.html
Sent from the R help mailing list archive at Nabble.com.
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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and provide commented, minimal, self-contained, reproducible code.
Re: [R] sampling dataframe based upon number of record occurrences
That worked great, thanks so much David!
On Wed, Mar 4, 2015 at 8:23 AM, David L Carlson dcarl...@tamu.edu wrote:
I'm not sure I understand, but I think you have a large data frame with
records and you want to construct a sample of that data frame that includes
no more than 3 records for each IDbyYear combination? You say there are
5589 unique combinations and your code uses a data frame called
fitting_set. Assuming this is the data frame you are describing, your code
will select all of the lines since fitting_set$IDbyYear[i] is always a
vector of length 1.
We need a reproducible example. The best way for you to give us that would
be to copy the result of dput(head(fitting_set, 10)). It would look
something like this plus the 6 other columns you mention except that I've
added dta - in front of structure() to create a data frame:
dta - structure(list(IDbyYear = c(42.24, 42.24, 42.24, 42.24, 42.24,
42.24, 45.32, 45.32, 45.36, 45.4, 45.4), SiteID = structure(c(1L,
1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L), .Label = c(A-Airport,
A-Bark Corral East), class = factor), Year = c(2006L, 2006L,
2006L, 2006L, 2006L, 2006L, 2008L, 2008L, 2009L, 2010L, 2010L
)), .Names = c(IDbyYear, SiteID, Year), class = data.frame,
row.names = c(NA,
-11L))
Now create a list of data frames, one for each IDbyYear:
dta.list - split(dta, dta$IDbyYear)
Now a function that will select 3 rows or all of them if there are fewer:
smp - function(dframe) {
ind - seq_len(nrow(dframe))
dframe[sample(ind, ifelse(length(ind)2, 3, length(ind))),]
}
Now take the samples and combine them into a single data frame:
sample - do.call(rbind, lapply(dta.list, smp))
sample
-
David L Carlson
Department of Anthropology
Texas AM University
College Station, TX 77840-4352
-Original Message-
From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Curtis
Burkhalter
Sent: Tuesday, March 3, 2015 3:23 PM
To: r-help@r-project.org
Subject: [R] sampling dataframe based upon number of record occurrences
Hello everyone,
I'm having trouble performing a task that is probably very simple, but
can't seem to figure out how to get my code to work. What I want to do is
use the sample function to pick records within in a dataframe, but only if
a column attribute value is repeated more than 3 times. So if you look at
the data below I have created a unique attribute value that corresponds to
every site by year combination (i.e. IDxYear). So you can see that for the
site called A-Airport it was sampled 6 times in 2006, A-Bank Corral
East was sampled twice in 2008. So what I want to do is randomly select 3
records for A-Airport in 2006 for the existing 6 records, but for A-Bark
Corral East in 2008 I just want to leave these records as they currently
are.
I've used the following code to try and accomplish this, but like I said I
can't get it to work so I'm clearly doing something wrong. If you could
check out the code and provide any suggestions that would be great. It
should be noted that there are 5589 unique IDxYear combinations so that's
why that number is in the code. If any further clarification is needed also
let me know.
boom=data.frame()
for (i in 1:5589){
boom[i,]=ifelse(length(fitting_set$IDbyYear[i]3),fitting_set[sample(nrow(fitting_set),3),],fitting_set)
}
boom
*IDbyYear* *SiteID * *Year*
*6 other column attributes*
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
45.32 A-Bark Corral East2008
45.32 A-Bark Corral East2008
45.36 A-Bark Corral East2009
45.40 A-Bark Corral East2010
45.40 A-Bark Corral East 2010
Thanks
--
Curtis Burkhalter
https://sites.google.com/site/curtisburkhalter/
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Curtis Burkhalter
https://sites.google.com/site/curtisburkhalter/
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
Re: [R] sampling dataframe based upon number of record occurrences
Since you indicated there are six more columns in the data.frame, getSample
modified below to take care of it.
getSample
function(x)
{
sites - unique(x$SiteID)
years - unique(x$Year)
result - data.frame()
x$ID - seq(1,nrow(x))
for (i in 1:length(sites))
{
for (j in 1:length(years))
{
if (nrow(x[as.character(x$SiteID)==as.character(sites[i])
x$Year==years[j],]) 3)
{
sampledID - sample(x[as.character(x$SiteID)==as.character(sites[i])
x$Year==years[j],]$ID,3,replace=FALSE)
for (k in 1:length(sampledID))
{
result - rbind(result,x[x$ID==sampledID[k],-ncol(x)])
}
}
}
}
names(result) - names(x)[-ncol(x)]
rownames(result) - NULL
return(result)
}
getSample(fitting.set)
IDbyYearSiteID Year
142.24 A-Airport 2006
242.24 A-Airport 2006
342.24 A-Airport 2006
--
View this message in context:
http://r.789695.n4.nabble.com/sampling-dataframe-based-upon-number-of-record-occurrences-tp4704144p4704155.html
Sent from the R help mailing list archive at Nabble.com.
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
[R] sampling dataframe based upon number of record occurrences
Hello everyone,
I'm having trouble performing a task that is probably very simple, but
can't seem to figure out how to get my code to work. What I want to do is
use the sample function to pick records within in a dataframe, but only if
a column attribute value is repeated more than 3 times. So if you look at
the data below I have created a unique attribute value that corresponds to
every site by year combination (i.e. IDxYear). So you can see that for the
site called A-Airport it was sampled 6 times in 2006, A-Bank Corral
East was sampled twice in 2008. So what I want to do is randomly select 3
records for A-Airport in 2006 for the existing 6 records, but for A-Bark
Corral East in 2008 I just want to leave these records as they currently
are.
I've used the following code to try and accomplish this, but like I said I
can't get it to work so I'm clearly doing something wrong. If you could
check out the code and provide any suggestions that would be great. It
should be noted that there are 5589 unique IDxYear combinations so that's
why that number is in the code. If any further clarification is needed also
let me know.
boom=data.frame()
for (i in 1:5589){
boom[i,]=ifelse(length(fitting_set$IDbyYear[i]3),fitting_set[sample(nrow(fitting_set),3),],fitting_set)
}
boom
*IDbyYear* *SiteID * *Year*
*6 other column attributes*
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
42.24 A-Airport 2006
45.32 A-Bark Corral East2008
45.32 A-Bark Corral East2008
45.36 A-Bark Corral East2009
45.40 A-Bark Corral East2010
45.40 A-Bark Corral East 2010
Thanks
--
Curtis Burkhalter
https://sites.google.com/site/curtisburkhalter/
[[alternative HTML version deleted]]
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] Sampling dataframe
Here are some options that may help you out. First, let's put the data in a format that can be cut-and-pasted into R. myData - read.table(textConnection(var1 var2 var3 1 111 2 312 3 813 4 614 51015 6 221 7 422 8 623 9 824 10 1025),header=TRUE,row.names=1) closeAllConnections() or use dput myData - structure(list(var1 = c(1L, 3L, 8L, 6L, 10L, 2L, 4L, 6L, 8L, 10L), var2 = c(1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L), var3 = c(1L, 2L, 3L, 4L, 5L, 1L, 2L, 3L, 4L, 5L)), .Names = c(var1, var2, var3), class = data.frame, row.names = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)) #Select data where v2=1 select_v2 - myData[myData$var2==1,] # sample two rows of select_v2 sampled_v2 - select_v2[sample(1:nrow(select_v2),2),] # select rows of var3 not equal to 1 select_v3 - myData[myData$v3 !=1,] # ?rbind may also come in useful. 2009/11/25 Ronaldo Reis Júnior chrys...@gmail.com: Hi, I have a table like that: datatest var1 var2 var3 1 1 1 1 2 3 1 2 3 8 1 3 4 6 1 4 5 10 1 5 6 2 2 1 7 4 2 2 8 6 2 3 9 8 2 4 10 10 2 5 I need to create another table based on that with the rules: take a random sample by var2==1 (2 sample rows for example): var1 var2 var3 1 1 1 1 4 6 1 4 in this random sample a get the 1 and 4 value on the var3, now I need to complete the table with var1==2 with the lines that var3 are not select on var2==1 The resulting table is: var1 var2 var3 1 1 1 1 4 6 1 4 7 4 2 2 8 6 2 3 10 10 2 5 the value 1 and 4 on var3 is not present in the var2==2. I try several options but without success. take a random value is easy, but I cant select the others value excluding the random selected values. Any help? Thanks Ronaldo -- 17ª lei - Seu orientador quer que você se torne famoso, de modo que ele possa, finalmente, se tornar famoso. --Herman, I. P. 2007. Following the law. NATURE, Vol 445, p. 228. -- Prof. Ronaldo Reis Júnior | .''`. UNIMONTES/DBG/Lab. Ecologia Comportamental e Computacional | : :' : Campus Universitário Prof. Darcy Ribeiro, Vila Mauricéia | `. `'` CP: 126, CEP: 39401-089, Montes Claros - MG - Brasil | `- Fone: (38) 3229-8192 | ronaldo.r...@unimontes.br | chrys...@gmail.com | http://www.ppgcb.unimontes.br/lecc | ICQ#: 5692561 | LinuxUser#: 205366 -- Favor NÃO ENVIAR arquivos do Word ou Powerpoint Prefira enviar em PDF, Texto, OpenOffice (ODF), HTML, or RTF. __ 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. __ 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.
[R] Sampling dataframe
Hi, I have a table like that: datatest var1 var2 var3 1 111 2 312 3 813 4 614 51015 6 221 7 422 8 623 9 824 10 1025 I need to create another table based on that with the rules: take a random sample by var2==1 (2 sample rows for example): var1 var2 var3 1 111 4 614 in this random sample a get the 1 and 4 value on the var3, now I need to complete the table with var1==2 with the lines that var3 are not select on var2==1 The resulting table is: var1 var2 var3 1 111 4 614 7 422 8 623 10 1025 the value 1 and 4 on var3 is not present in the var2==2. I try several options but without success. take a random value is easy, but I cant select the others value excluding the random selected values. Any help? Thanks Ronaldo -- 17ª lei - Seu orientador quer que você se torne famoso, de modo que ele possa, finalmente, se tornar famoso. --Herman, I. P. 2007. Following the law. NATURE, Vol 445, p. 228. -- Prof. Ronaldo Reis Júnior | .''`. UNIMONTES/DBG/Lab. Ecologia Comportamental e Computacional | : :' : Campus Universitário Prof. Darcy Ribeiro, Vila Mauricéia | `. `'` CP: 126, CEP: 39401-089, Montes Claros - MG - Brasil | `- Fone: (38) 3229-8192 | ronaldo.r...@unimontes.br | chrys...@gmail.com | http://www.ppgcb.unimontes.br/lecc | ICQ#: 5692561 | LinuxUser#: 205366 -- Favor NÃO ENVIAR arquivos do Word ou Powerpoint Prefira enviar em PDF, Texto, OpenOffice (ODF), HTML, or RTF. __ 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.
