R help - Aug 2009 - problem with recording numeric output into another dataframe

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
-- 
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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@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@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

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