[R] problem with recording numeric output into another dataframe

[Rnewbie]

Thank you very much for the reply. The thing I want to achieve in the end is
to use dataframe1 as a master dataframe, and get values from multiple
dataframes to dataframe1, so that I can analyze the data altogether, like
this:

ID    value1     value2     value3
a      100         123         456
b                     321         654
c      200                        564

I first created an empty column in dataframe1, and then I tried to record
the values into this column at the corresponding rows, but I had a problem.
I was not able to tell R "please do nothing when there's not a match".

DF1<-transform(DF1, value1=rep(NA, nrow(DF1)))

for (i in seq(1:nrow(DF1))) {
          if (is.numeric(DF2[grep(DF1[i, "ID"], DF2$ID), "value"])==T)
{DF1<-transform(DF1, value1[i]<-DF2[grep(DF1[i, "ID"], DF2$ID), "value"])} 
else {print("bingo!")}
}

but the is.numeric() test was TRUE even when there was not a match, and it
resulted in an error.

If I do it reversely, I'll get all "bingo!"
 
for (i in seq(1:nrow(DF1))) {
          if (is.numeric(DF2[grep(DF1[i, "ID"], DF2$ID), "value"])==T)
{print("bingo!")} else {DF1<-transform(DF1, value1[i]<-DF2[grep(DF1[i,
"ID"], DF2$ID), "value"])} 
}


Any ideas how I can get what I wanted?



Henrique Dallazuanna wrote:
> 
> Try this:
> g <- sapply(DF1$ID, grep, x = DF2$ID)
> transform(DF2[unlist(g),],ID = DF1$ID[which(g > 0)])
> 
> On Thu, Aug 6, 2009 at 1:41 PM, Rnewbie <xuancj at yahoo.com> wrote:
> 
>>
>> dear all,
>>
>> I have two dataframes
>>
>> dataframe1
>> ID
>> a
>> b
>> c
>>
>> dataframe2
>> ID       value
>> a;W      100
>> X;c      200
>> Y;Z      300
>>
>> I wanted to match the IDs from the two dataframes and record the values
>> into
>> a new column of dataframe1 at the corresponding rows. This is what I
>> expect:
>>
>> dataframe1
>> ID     value
>> a      100
>> b
>> c      200
>>
>> I tried doing it like this:
>>
>> for (i in seq(1:nrow(dataframe1))) {
>>           dataframe1[i,"value"]<-dataframe2[grep(dataframe1[i,"ID"],
>> dataframe2$ID),"value"]
>> }
>>
>> but I failed. I was able to extracted the values from dataframe2 but not
>> able to record the values in the corresponding rows of dataframe1.
>>
>> I would appreciate any suggestions. Thanks in advance.
>>
>> Jim
>> --
>> View this message in context:
>> http://www.nabble.com/problem-with-recording-numeric-output-into-another-dataframe-tp24850155p24850155.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> 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.
>>
> 
> 
> 
> -- 
> Henrique Dallazuanna
> Curitiba-Paraná-Brasil
> 25° 25' 40" S 49° 16' 22" O
> 
> 	[[alternative HTML version deleted]]
> 
> 
> ______________________________________________
> 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.
> 
> 

-- 
View this message in context: http://www.nabble.com/problem-with-recording-numeric-output-into-another-dataframe-tp24850155p24865628.html
Sent from the R help mailing list archive at Nabble.com.