[R] merging two specific rows in a DF

[jim holtman]

try this:

> x <- read.table(text = "C1      C2      TYPE
+ 10      20      A
+ 33      44      B
+ 66      80      A
+ 111     140     B
+ 144     220     B
+ 300     340     A
+ 380     449     A
+ 455     500     B
+ 510     520     A
+ 540     580     B", header = TRUE, as.is = TRUE)
> # mark successive rows that are different
> x$diff <- c(TRUE, head(x$TYPE, -1) != tail(x$TYPE, -1))
> # create groups where adjacent rows are the same
> x$group <- cumsum(x$diff)
> # now process each group to get min/max
> result <- lapply(split(x, x$group), function(.same){
+     c1Min <- min(.same$C1)
+     c2Max <- max(.same$C2)
+     # put result back into first row and just return its value
+     .same$C1[1L] <- c1Min
+     .same$C2[1L] <- c2Max
+     .same[1,1:3]  # return value drop off the extra columns we added
+     })
> # combine back together
> do.call(rbind, result)
   C1  C2 TYPE
1  10  20    A
2  33  44    B
3  66  80    A
4 111 220    B
5 300 449    A
6 455 500    B
7 510 520    A
8 540 580    B
>
>
>


On Mon, Nov 26, 2012 at 5:24 AM, karthicklakshman
<karthick.lakshman at gmail.com> wrote:
> Hello members,
>
> I have this data frame with 3 columns,
> C1      C2      TYPE
> 10      20      A
> 33      44      B
> 66      80      A
> 111     140     B
> 144     220     B
> 300     340     A
> 380     449     A
> 455     500     B
> 510     520     A
> 540     580     B
>
> Here,  the rows 4 , 5 has type "B" and similarly 6,7 has "A" . I need to
> merge these rows in a way to get the output with unique type, something like
> below, where the lowest value from DF$C1 and  highest value from DF$C2
> corresponding to rows 4,5 are picked.
>
> C1      C2      TYPE
> 10      20      A
> 33      44      B
> 66      80      A
> 111     220     B
> 300     449     A
> 455     500     B
> 510     520     A
> 540     580     B
>
> I Request your kind help..
> Regards,
> karthick
>
>
>
>
> --
> View this message in context: http://r.789695.n4.nabble.com/merging-two-specific-rows-in-a-DF-tp4650826.html
> Sent from the R help mailing list archive at Nabble.com.
>
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-- 
Jim Holtman
Data Munger Guru

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Tell me what you want to do, not how you want to do it.