[R] Merge usage to update data.frame

[Mario Valle]

That is! Match, not merge is the solution.
Ahhh, memory, memory...
Thanks a lot!
			mario

On 07-Jun-10 0:09, jim holtman wrote:
> try this:
>
>> a
>     V1 V2
> 1 AAA  1
> 2 BBB  2
> 3 CCC  3
>> u
>     V1 V2
> 1 BBB 22
>> a$V2[match(u$V1, a$V1)]<- u$V2
>> a
>     V1 V2
> 1 AAA  1
> 2 BBB 22
> 3 CCC  3
>>
>
>
> On Sun, Jun 6, 2010 at 12:41 PM, Mario Valle<mvalle at cscs.ch>  wrote:
>> Good morning!
>> I have two datasets with the same structure, one containing all my values
>> and the second one that update same of these values (see example below).
>> I want to create a data.frame with all the values of the first dataset
>> except when an entry is present in the second dataset, in which case the
>> second dataset value is taken.
>>
>> Is there a better method than my last line kludge?
>> Thanks for your help!
>>                         mario
>>
>>
>> t1<- textConnection("AAA 1
>> BBB 2
>> CCC 3")
>> a<- read.table(t1, stringsAsFactors=FALSE)
>> close(t1)
>> t2<- textConnection("BBB 22")
>> u<- read.table(t2, stringsAsFactors=FALSE)
>> close(t2)
>> m<- merge(a, u, by="V1", all.x=TRUE)
>> out<- data.frame(V1=m$V1, V2=ifelse(is.na(m$V2.y), m$V2.x, m$V2.y))
>>
>>
>> --
>> Ing. Mario Valle
>> Data Analysis and Visualization Group            |
>> http://www.cscs.ch/~mvalle
>> Swiss National Supercomputing Centre (CSCS)      | Tel:  +41 (91) 610.82.60
>> v. Cantonale Galleria 2, 6928 Manno, Switzerland | Fax:  +41 (91) 610.82.82
>>
>> ______________________________________________
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>> 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.
>>
>
>
>

-- 
Ing. Mario Valle
Data Analysis and Visualization Group            | 
http://www.cscs.ch/~mvalle
Swiss National Supercomputing Centre (CSCS)      | Tel:  +41 (91) 610.82.60
v. Cantonale Galleria 2, 6928 Manno, Switzerland | Fax:  +41 (91) 610.82.82