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identify data points by certain criteria

4 messages · David Winsemius, arun, Ye Lin

David Winsemius
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On Jun 12, 2013, at 5:55 PM, Ye Lin wrote:

            

      
      
      
    

        
While you are waiting for an answer you might want to read the Posting Guide:

http://www.R-project.org/posting-guide.html

Points to pay special attention to: Plain-text. Posting code. Posting examples in form that can be pasted into console session (dump or dput functions). Providing context for problem (such as describing the conventions for your time-scale)  and your background (since this looks like a homework exercise.)

            

      
      
      
    

        

      
      
    

        
David Winsemius
Alameda, CA, USA

  
  


  


      

    

    

      
      

        


  

        

      arun
    

    

      
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Hi,
Not clear about the 'Time' column.
dat1<- read.table(text="
Time??? Var1????? Var2
00:00??? 1????????????? 0
00:01??? 0????????????? 0
00:02??? 1????????????? 0
00:03??? 1????????????? 0
00:04??? 0????????????? 0
00:05??? 1????????????? 0
00:06??? 1????????????? 0
00:07??? 1????????????? 0
00:08??? 1????????????? 0
00:09??? 0????????????? 0
00:10??? 1????????????? 0
00:11??? 1????????????? 0
00:12??? 1????????????? 0
00:13??? 0????????????? 0
",sep="",header=TRUE,stringsAsFactors=FALSE)


indx<-which(rowSums(dat1[,-1])==0)
dat1[indx[which.max(c(1,diff(as.numeric(gsub(".*:","",dat1[,1][indx])))))],]
#??? Time Var1 Var2
#10 00:09??? 0??? 0
dat1[indx[which.max(c(1,diff(as.numeric(gsub(".*:","",dat1[,1][indx])))))],"Time"]
#[1] "00:09"


A.K.



----- Original Message -----
From: Ye Lin <yelin at lbl.gov>
To: R help <r-help at r-project.org>
Cc: 
Sent: Wednesday, June 12, 2013 8:55 PM
Subject: [R] identify data points by certain criteria

Hey I want to identify data points by criteria, here is an example of my
1min data

Time? ?  Var1? ? ? Var2
00:00? ? 1? ? ? ? ? ? ? 0
00:01? ? 0? ? ? ? ? ? ? 0
00:02? ? 1? ? ? ? ? ? ? 0
00:03? ? 1? ? ? ? ? ? ? 0
00:04? ? 0? ? ? ? ? ? ? 0
00:05? ? 1? ? ? ? ? ? ? 0
00:06? ? 1? ? ? ? ? ? ? 0
00:07? ? 1? ? ? ? ? ? ? 0
00:08? ? 1? ? ? ? ? ? ? 0
00:09? ? 0? ? ? ? ? ? ? 0
00:10? ? 1? ? ? ? ? ? ? 0
00:11? ? 1? ? ? ? ? ? ? 0
00:12? ? 1? ? ? ? ? ? ? 0
00:13? ? 0? ? ? ? ? ? ? 0

I want to identify the data points where Var1=0 and Var2=0, ( in this
example shud be the points highlighted above), then calculate the time
duration between these data points, (in this example, shud be 3min, 5 min
and 4min), then identify the starting point of the max time duration ( in
this example shud be the starting point of 5-min-duration, return the data
points at 00:09), finally return the value in "Time" column ( in this
example shud be "00:09")

Thanks for your help!

??? [[alternative HTML version deleted]]

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