CODEWITHSUNDEEP
rvectorbooleancounter
enroute
enroute

Reputation: 183

counting number of true/talse periods in r

I have a boolean vector derived from a time series. It basically looks like this: c(true, false, true, true, false, false, false, true, true...).

I want to count the periods in which the vector is true. Example: for a vector like this: c(true, true, false, true) it would be 2 (1 long true period in the beginning, 1 short in the end).

the vector can contain NAs in the beginning.

I thought of something like:

aaa <- c(NA,F,T,T,T,F)    
for(j in 1:(length(aaa)-1)){  
  if(aaa[j]!=aaa[j+1]){  
    # add a counter that returns [1]  
  }  
}

=================================================

edit: This works fine for me:

data.frame("#"=unlist(rle(aaa)[1]),"length"=unlist(rle(aaa)[2]))

Upvotes: 0

Views: 126

Answers (1)

Miff
Miff

Reputation: 7941

How about this:

aaa[is.na(aaa)] <- FALSE
sum(rle(aaa)$values)

Convert NAs to FALSE, and the see how many TRUE values there are in the run length encoding (TRUE is stored as 1, FALSE as zero).

Upvotes: 1

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