Re: [R] data frame search

From: Bart Joosen <bartjoosen_at_hotmail.com>
Date: Sun 25 Jun 2006 - 04:14:41 EST

Thanks, couldn't find this function,

Best regards

Bart

> Try this:
>
> which(DF1 == 4, arr.ind = TRUE)
>
>
> On 6/24/06, Bart Joosen <bartjoosen@hotmail.com> wrote:
>> Hi,
>>
>> I want to make a data frame which contains the positions of some searched
>> values in another data frame.
>>
>> Like:
>> Dataframe 1:
>>
>> 1 2 3 4 1 2 3 4
>> 2 3 4 1 2 3 4 2
>> 4 1 2 3 2 3 4 1
>>
>> Let's say I searched on "4", then Dataframe 2 should contain:
>> x y
>> 1 4
>> 1 8
>> 2 3
>> 2 7
>> 3 1
>> 3 7
>>
>> I have written a routine, but it seems to me that it isn't that perfect:
>> x<- 0
>>
>> y<- 0
>>
>> for (j in 1:ncol(df)) {
>>
>> for (i in 1:nrow(df)) {
>>
>> if (df[i,j] == 3) {
>>
>> x <- c(x,i)
>>
>> y <- c(y,j)
>>
>> }
>>
>> }
>>
>> }
>>
>> df2 <- data.frame(x,y)
>>
>> df2 <- df2[-1,]
>>
>> Can someone come up with an elegant/faster solution, because the ultimate
>> goal of this routine is to analyze an jpg image.
>>
>> Kind regards
>>
>> Bart
>



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