R help - Feb 2012 - DF grouping

Hello Members,

I need to group a data.frame in a a specific way, like shown below,

DF raw is like this,

id col1 col2 score
1  A      B       40
2  B      C       55
3  C      D       4000
4  D      E        100
5  E       F        300

I want the out put as

List
[1]
A B C
[2]
D E
[3]
F
Basically the split should be based on the DF$score > 200, and all the col1
and col2 values should be aggrigated.

Request your kind help,

Regards,
karthick

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On Sun, Feb 12, 2012 at 07:07:26AM -0800, karthicklakshman
wrote:
> Hello Members,
> 
> I need to group a data.frame in a a specific way, like shown below,
> 
> DF raw is like this,
> 
> id col1 col2 score
> 1  A      B       40
> 2  B      C       55
> 3  C      D       4000
> 4  D      E        100
> 5  E       F        300
> 
> I want the out put as
> 
> List
> [1]
> A B C
> [2]
> D E
> [3]
> F
> Basically the split should be based on the DF$score > 200, and all the
col1
> and col2 values should be aggrigated.
Hi.

Is it always true that DF[i, "col2"] == DF[i+1, "col1"]?
If yes, then try the following

  # dput() of DF
  DF <- structure(list(col1 = structure(1:5, .Label = c("A",
"B", "C",
  "D", "E"), class = "factor"), col2 =
structure(1:5, .Label = c("B",
  "C", "D", "E", "F"), class =
"factor"), score = c(40L, 55L, 4000L,
  100L, 300L)), .Names = c("col1", "col2",
"score"), class = "data.frame",
  row.names = c(NA, -5L))
 
  # linearize col1, col2
  objects <- c(as.character(DF[1, "col1"]), as.character(DF[,
"col2"]))
  scores <- c(0, DF[, "score"])
 
  # output as list of vectors
  out1 <- split(objects, cumsum(scores > 200))
  out1

  $`0`
  [1] "A" "B" "C"
  
  $`1`
  [1] "D" "E"
  
  $`2`
  [1] "F"

  # output as list of character strings
  out2 <- lapply(out1, paste, collapse=" ")
  out2

  $`0`
  [1] "A B C"
  
  $`1`
  [1] "D E"
  
  $`2`
  [1] "F"

Hope this helps.

Petr Savicky.

Dear Petr Savicky,

Thank you very much for the solution.
your script really worked for my DF,  and yes as per your guess , its always
---> DF[i, "col2"] == DF[i+1, "col1"]

Regards,
karthick

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Hello Petr Savicky, hello all,

I have a situation similar to the previous one,
I need to group a data.frame in a specific way,

col1 col2   score
2873  3192   319
4268  4451   183
5389  5534   145
6622 10622  4000
12631 17853  5222
20408 20615   207
21595 21838   243
23121 23139    18

the out put should be like,

[1] 
2873  3192   4268  4451   5389  5534  6622 10622 
[2] 
10622  12631
[3] 
17853 20408 20615  21595 21838   23121 23139 

Basically the split should be based on the DF$score > 500, and all the col1
and col2 values should be aggregated. but  DF[i, "col2"] != DF[i+1,
"col1"]

Your inputs will be very helpful
Thank you
Karthick




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