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who can give me some hint?

6 messages · Simon Pickett, Richard Cotton, Gabor Grothendieck +1 more

Simon Pickett
# 
Hi All,
Date    Dtime Hour Min Second               Rep
51 2006-02-22 14:52:18   14  52     18  useractivity_act
52 2006-02-22 14:52:18   14  52     18                 4
55 2006-02-22 14:52:49   14  52     49                 4
57 2006-02-22 14:52:51   14  52     51                 4
58 2006-02-22 14:52:52   14  52     52                 3
60 2006-02-22 14:54:42   14  54     42 useractivity_idle

I want to change act_2 to
         Date    Dtime Hour Min Second               Rep

51 2006-02-22 14:52:18   14  52     18  useractivity_act

52 2006-02-22 14:52:18   14  52     18                 4
58 2006-02-22 14:52:52   14  52     52                 3
60 2006-02-22 14:54:42   14  54     42 useractivity_idle

in other word, I want to keep 1st if there are many repeated value, I made 
the program as:

Not sure what you mean here, can you describe this more fully?

It seems that you might be able to avoid using loops if all you want to do 
is select only the rows where column x is less than a threshold value.
e.g.
a<-a[a$columnx<1000,]

Hope this helps

Simon.


rm_r<-function(act_2){
 dm<-dim(act_2)[1]-1
 for(i in 2:dm){

 if(act_2$Rep[i+1]==act_2$Rep[i]){
   act_2<-act_2[-(i+1),]
   }else{
   act_2<-act_2
   }
 }
return(act_2)
}

when it moved one row on 1st loop, i should still start 2 but it become 3 at 
2nd loop, if I add i<-i-1, then i go to 1
seems not reasonbale. How should I modify it`?

Tammy
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--------------------------------------------------------------------------------
Richard Cotton
# 
Please don't repeatedly post the same question - it is irritating, and 
you're not likely to get a favourable response.  Try explaining your 
problem more clearly.  What is the condition that you want to use to keep 
rows?  (In your example, each of the rows is different, yet you kept some 
and discarded others.)

If you just want to discard some rows form a data frame, you don't need a 
loop, e.g.

dfr <- data.frame(x=1:10, y=runif(10))
dfr[c(1,3,5,5),]

Regards,
Richie.

Mathematical Sciences Unit
HSL



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Gabor Grothendieck
# 
I assume the problem is to only keep those rows whose
Rep value is not equal to the Rep value in the prior row.
In that case just compare c("", Rep[-nr]) to Rep and
use the resulting vector, ix, to select out rows.
Rep <- as.character(act_2$Rep) could
be simplified to Rep <- act_2$Rep if Rep
is already known to be "character".


Lines <- "Date    Dtime Hour Min Second               Rep
51 2006-02-22 14:52:18   14  52     18  useractivity_act
52 2006-02-22 14:52:18   14  52     18                 4
55 2006-02-22 14:52:49   14  52     49                 4
57 2006-02-22 14:52:51   14  52     51                 4
58 2006-02-22 14:52:52   14  52     52                 3
60 2006-02-22 14:54:42   14  54     42 useractivity_idle"

act_2 <- read.table(textConnection(Lines), header = TRUE, as.is = TRUE)

nr <- nrow(act_2)
Rep <- as.character(act_2$Rep)
ix <- Rep != c("", Rep[-nr])
act_2[ix]
On Thu, Mar 12, 2009 at 6:25 AM, Tammy Ma <metal_licaling at live.com> wrote:
Gabor Grothendieck
# 
Its not clear what "more flexible refers to".  The posted solution
already produces the sample output you showed.  What else
should it do?
On Thu, Mar 12, 2009 at 8:15 AM, Tammy Ma <metal_licaling at live.com> wrote: