[R] First value in a row
arun
smartpink111 at yahoo.com
Wed Jul 25 05:50:45 CEST 2012
Hi,
I think it was due to a row with all the NAs. I hope it happens rarely.
In those cases, you can assign NAs from looking at the list.
dat2<-data.frame(t(dat1[,3:5]))
dat3<-lapply(dat2,function(x) tail(x[!is.na(x)],1))
dat3
$X1
[1] 0.6
$X2
[1] 0.3
$X3
[1] 0.1
$X4
numeric(0)
dat3$X4<-NA
dat4<-data.frame(dat1,NewColumn=unlist(dat3))
rownames(dat4)<-1:nrow(dat4)
dat4
# Lat Lon x1 x2 x3 NewColumn
#1 1 12 0.4 0.5 0.6 0.6
#2 1 12 0.2 0.3 NA 0.3
#3 1 11 0.1 NA NA 0.1
#4 1 10 NA NA NA NA
##################################
#Another way elegant
#or you can find the NA by using
dat3<-lapply(dat2,function(x) tail(x[!is.na(x)],1))dat4<-ifelse(sapply(dat3,length)==0,NA,dat3)
dat5<-data.frame(dat1,NewColumn=unlist(dat4))
rownames(dat5)<-1:nrow(dat5)
dat5
Lat Lon x1 x2 x3 NewColumn
1 1 12 0.4 0.5 0.6 0.6
2 1 12 0.2 0.3 NA 0.3
3 1 11 0.1 NA NA 0.1
4 1 10 NA NA NA NA
A.K.
----- Original Message -----
From: Camilo Mora <cmora at dal.ca>
To: arun <smartpink111 at yahoo.com>
Cc:
Sent: Tuesday, July 24, 2012 11:30 PM
Subject: Re: First value in a row
Hi Arun,
It works partially.... your script skip those rows full of NAs causing a different vector size, which then prevents merging the results to the original database. Any way to keep rows with all NAs?
C
Camilo Mora, Ph.D.
Department of Geography, University of Hawaii
Currently available in Colombia
Phone: Country code: 57
Provider code: 313
Phone 776 2282
From the USA or Canada you have to dial 011 57 313 776 2282
http://www.soc.hawaii.edu/mora/
Quoting arun <smartpink111 at yahoo.com>:
>
>
> Hi Camilo,
>
> You can either use Henrik's or mine to find it,
> unlist(apply(dat1[,-(1:2)],1,function(x) tail(x[!is.na(x)],1)))
> x3 x2 x1
> 0.6 0.3 0.1
>
> #or you can use my functiton
>
> dat3<-data.frame(NewColumn=c(unlist(lapply(dat2,function(x) tail(x[!is.na(x)],1))),NA))
> dat4<-data.frame(dat1,dat3)
> rownames(dat4)<-1:nrow(dat4)
> dat4
> # Lat Lon x1 x2 x3 NewColumn
> #1 1 12 0.4 0.5 0.6 0.6
> #2 1 12 0.2 0.3 NA 0.3
> #3 1 11 0.1 NA NA 0.1
> #4 1 10 NA NA NA NA
>
> A.K.
>
>
>
>
>
>
> ----- Original Message -----
> From: Camilo Mora <cmora at dal.ca>
> To: arun <smartpink111 at yahoo.com>
> Cc: Henrik Singmann <henrik.singmann at psychologie.uni-freiburg.de>; R help <r-help at r-project.org>
> Sent: Tuesday, July 24, 2012 10:56 PM
> Subject: Re: First value in a row
>
> Hi Henrik and Arun,
>
> I now understand the script you provided. Very smart solution I think. I wonder, however, if there is an alternative way as to count the last number in a row?.
> For instance, considering the following dataframe
>
> dat1<-read.table(text="
> Lat Lon x1 x2 x3
> 01 12 .4 .5 .6
> 01 12 .2 .3 NA
> 01 11 .1 NA NA
> 01 10 NA NA NA
> ",sep="",header=TRUE)
>
> the last value (from left to right) should be:
> .6
> .3
> .1
> NA
>
> NAs are always consecutive once they appear.
>
> Thanks again,
>
> Camilo
>
>
> Camilo Mora, Ph.D.
> Department of Geography, University of Hawaii
> Currently available in Colombia
> Phone: Country code: 57
> Provider code: 313
> Phone 776 2282
> From the USA or Canada you have to dial 011 57 313 776 2282
> http://www.soc.hawaii.edu/mora/
>
>
>
> Quoting arun <smartpink111 at yahoo.com>:
>
>> Hi Henrik,
>>
>> Thanks for testing it to a different dataset. I didn't test it at that time to multiple conditions. Probably, apply is a better method.
>>
>>
>> Anyway, you can still get the same result by doing this:
>>
>> dat1<-read.table(text="
>> Lat Lon x1 x2 x3
>> 01 10 NA NA .1
>> 01 11 .4 NA .3
>> 01 12 NA .5 .6
>> ",sep="",header=TRUE)
>> dat2<-data.frame(t(dat1[,3:5]))
>> dat3<-data.frame(dat1,NewColumn=unlist(lapply(dat2,function(x) x[!is.na(x)][1])))
>> row.names(dat3)<-1:nrow(dat3)
>> dat3
>> # Lat Lon x1 x2 x3 NewColumn
>> #1 1 10 NA NA 0.1 0.1
>> #2 1 11 0.4 NA 0.3 0.4
>> #3 1 12 NA 0.5 0.6 0.5
>>
>> #Now, to a slightly different dataset
>> dat1<-read.table(text="
>> Lat Lon x1 x2 x3
>> 01 10 NA NA NA
>> 01 11 NA NA .3
>> 01 12 NA .6 NA
>> ",sep="",header=TRUE)
>> dat2<-data.frame(t(dat1[,3:5]))
>> dat3<-data.frame(dat1,NewColumn=unlist(lapply(dat2,function(x) x[!is.na(x)][1])))
>> row.names(dat3)<-1:nrow(dat3)
>> dat3
>> #Lat Lon x1 x2 x3 NewColumn
>> #1 1 10 NA NA NA NA
>> #2 1 11 NA NA 0.3 0.3
>> #3 1 12 NA 0.6 NA 0.6
>>
>>
>> I hope this works well.
>>
>>
>> A.K.
>>
>>
>>
>>
>> ----- Original Message -----
>> From: Henrik Singmann <henrik.singmann at psychologie.uni-freiburg.de>
>> To: arun <smartpink111 at yahoo.com>
>> Cc: Camilo Mora <cmora at dal.ca>; R help <r-help at r-project.org>
>> Sent: Tuesday, July 24, 2012 10:18 AM
>> Subject: Re: First value in a row
>>
>> Hi,
>>
>> As Arun's idea was also my first idea let me pinpoint the problem of this solution.
>> It only works if the data in question (i.e., columns x1 to x3) follow the pattern of the example data insofar that the NAs form a triangle like structure. This is so because it loops over columns instead of rows and takes advantage of the triangle NA structure.
>>
>> For example, slightly changing the data leads to a result that does not follow the description of Camilo seem to want:
>>
>> dat1<-read.table(text="
>> Lat Lon x1 x2 x3
>> 01 10 NA NA .1
>> 01 11 .4 NA .3
>> 01 12 NA .5 .6
>> ",sep="",header=TRUE)
>>
>> # correct answer from description would be .1, .4, .5
>>
>> # arun's solution:
>> data.frame(dat1,NewColumn=rev(unlist(lapply(dat1[,3:5],function(x) x[!is.na(x)][1]))))
>>
>> # x3 x2 x1
>> # 0.1 0.5 0.4
>>
>> # my solution:
>> apply(dat1[,-(1:2)], 1, function(x) x[!is.na(x)][1])
>>
>> # [1] 0.1 0.4 0.5
>>
>> So the question is, what you want and how the data looks.
>>
>> Cheers,
>> Henrik
>>
>>
>> Am 24.07.2012 14:27, schrieb arun:
>>> Hi,
>>>
>>> Try this:
>>>
>>> dat1<-read.table(text="
>>> Lat Lon x1 x2 x3
>>> 01 10 NA NA .1
>>> 01 11 NA .2 .3
>>> 01 12 .4 .5 .6
>>> ",sep="",header=TRUE)
>>>
>>> dat2<-dat1[,3:5]
>>> dat3<-data.frame(dat1,NewColumn=rev(unlist(lapply(dat2,function(x) x[!is.na(x)][1]))))
>>> row.names(dat3)<-1:nrow(dat3)
>>> dat3
>>> Lat Lon x1 x2 x3 NewColumn
>>> 1 1 10 NA NA 0.1 0.1
>>> 2 1 11 NA 0.2 0.3 0.2
>>> 3 1 12 0.4 0.5 0.6 0.4
>>>
>>> A.K.
>>>
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From: Camilo Mora <cmora at dal.ca>
>>> To: r-help at r-project.org
>>> Cc:
>>> Sent: Tuesday, July 24, 2012 2:48 AM
>>> Subject: [R] First value in a row
>>>
>>> Hi.
>>>
>>> This is likely a trivial problem but have not found a solution. Imagine the following dataframe:
>>>
>>> Lat Lon x1 x2 x3
>>> 01 10 NA NA .1
>>> 01 11 NA .2 .3
>>> 01 12 .4 .5 .6
>>>
>>> I want to generate another column that consist of the first value in each row from columns x1 to x3. That is
>>>
>>> NewColumn
>>> .1
>>> .2
>>> .4
>>>
>>> Any input greatly appreciated,
>>>
>>> Thanks,
>>>
>>> Camilo
>>>
>>>
>>> Camilo Mora, Ph.D.
>>> Department of Geography, University of Hawaii
>>>
>>> ______________________________________________
>>> 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.
>>>
>>>
>>
>> --
>> Dipl. Psych. Henrik Singmann
>> PhD Student
>> Albert-Ludwigs-Universität Freiburg, Germany
>> http://www.psychologie.uni-freiburg.de/Members/singmann
>>
>>
>>
>
>
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