[R] merge dataframes

[Rui Barradas]

Hello,

Or use ?all.equal.

all.equal(dat2[52, 1], dat1[5, 1])  # TRUE


Hope this helps,

Rui Barradas

Em 03-07-2013 15:18, David Carlson escreveu:
> In addition to reading Frequently Asked Questions Section 7.31, you
> should always run your own code before posting. Yours does not work.
> Spend some time reading one or more of the R tutorials and learn
> about vectorization. It will save you time and typing. There are
> many to choose from at
>
> http://cran.r-project.org/other-docs.html
>
> Do not try to match decimal values. Instead create an index value
> that is a character string. Then you can match the character
> strings:
>
>> dat1<-data.frame(x=c(1.0,1.2,3.2,4.0,5.1),y=c(23,17,12,27,8))
>> dat2 <- data.frame(x=seq(0.1,6,by=0.1),y=rep(0,60)) # Errors in
> your code corrected here
>> dat1$xc <- sprintf("%1.1f", dat1$x, 1) # Create dat1 index value
> as character
>> dat2$xc <- sprintf("%1.1f", dat2$x, 1) # Create dat2 index value
> as character
>> dat2[match(dat1$xc, dat2$xc),] <- dat1 # update dat2 with dat1
>> dat2[dat2$y>0,] # Check the results
>       x  y  xc
> 10 1.0 23 1.0
> 12 1.2 17 1.2
> 32 3.2 12 3.2
> 40 4.0 27 4.0
> 51 5.1  8 5.1
>> dat1
>      x  y  xc
> 1 1.0 23 1.0
> 2 1.2 17 1.2
> 3 3.2 12 3.2
> 4 4.0 27 4.0
> 5 5.1  8 5.1
>
> -------------------------------------
> David L Carlson
> Associate Professor of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
>
>
> -----Original Message-----
> From: r-help-bounces at r-project.org
> [mailto:r-help-bounces at r-project.org] On Behalf Of jim holtman
> Sent: Wednesday, July 3, 2013 7:22 AM
> To: André de Boer
> Cc: R mailing list
> Subject: Re: [R] merge dataframes
>
> FAQ 7.31
>
>
> On Wed, Jul 3, 2013 at 7:55 AM, Andri de Boer <rnieuws at gmail.com>
> wrote:
>
>> Hello,
>>
>> I have two dataframes:
>> dat1<-data.frame(x=c(1.0,1.2,3.2,4.0,5.1),y=c(23,17,12,27,8))
>> dat2<-data.frame(x=seq(0,6,by=0.1),y=rep(0,60)))
>>
>> I want to replace the corresponding rows of dat2 with the ones of
> dat1.
>> I tried:
>>
>> for(i in 1:nrow(dat1))
>> {
>>    dat2[dat2$x==dat1[i,1],2]<-dat1[i,2]
>> }
>>
>> But I discovered that not every 5.1 is equal:
>>
>>> dat2[52,1][1] 5.1> dat1[5,1][1] 5.1> dat2[52,1]==dat1[5,1][1]
> FALSE
>>
>>
>>
>> How to solve this?
>>
>>
>>
>> Regards,
>>
>> Andri
>>
>>          [[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.
>>
>>
>
>