[R] First value in a row

arun smartpink111 at yahoo.com
Wed Jul 25 07:38:45 CEST 2012


Hi Camilo,

Glad it worked well.  


You mentioned replacing zeros with 1s.  You can use the same function, replace NA by 1. 


dat4<-ifelse(sapply(dat3,length)==0,1,dat3)


A.K.



----- Original Message -----
From: Camilo Mora <cmora at dal.ca>
To: arun <smartpink111 at yahoo.com>
Cc: 
Sent: Wednesday, July 25, 2012 1:15 AM
Subject: Re: First value in a row

Thanks Arun,

Your funbction is the most promising. I am trying to replace Zeros with 1s and see it that works. I have this script within a loop so I can not replace by hand 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,
> 
> I hope the second solution in my last email works for you.
> 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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