I have the following sample
id <- c("a","b","a","b","a","a","a","a","b","b","c")
SOG <- c(4,4,0,0,0,0,0,0,0,0,9)
data <- data.frame(id,SOG)
I would like in a new column the cumulative value when SOG == 0. with the following code
tmp <- rle(SOG) #run length encoding:
tmp$values <- tmp$values == 0 #turn values into logicals
tmp$values[tmp$values] <- cumsum(tmp$values[tmp$values]) #cumulative sum of TRUE values
inverse.rle(tmp) #inverse the run length encoding
I create the column "stop":
data$Stops <- inverse.rle(tmp)
and I can get in it:
[1] 0 0 1 1 1 1 1 1 1 1 0
But I would like to have instead
[1] 0 0 1 2 3 3 3 3 4 4 0
I mean that when the level of the factor "id" is different from the previous row, I want to jump to the next "stop" (i+1).
have a look a the dplyr
package
library(dplyr)
data %>%
mutate(
Stops = ifelse(
SOG > 0,
0,
cumsum(SOG == 0 & lag(id) != id)
)
)
We can try
library(data.table)
setDT(data1)[, v1 := if(all(!SOG)) c(TRUE, id[-1]!= id[-.N]) else
rep(FALSE, .N), .(grp = rleid(SOG))][,cumsum(v1)*(!SOG)]
#[1] 0 0 1 2 3 3 3 3 4 4 0 0 0 0 5 5 0 6 6 0
Using the old data
setDT(data)[, v1 := if(all(!SOG)) c(TRUE, id[-1]!= id[-.N])
else rep(FALSE, .N), .(grp = rleid(SOG))][,cumsum(v1)*(!SOG)]
#[1] 0 0 1 2 3 3 3 3 4 4 0
id <- c("a","b","a","b","a","a","a","a","b","b","c","a","a","a","a","a","a","a","a", "a")
SOG <- c(4,4,0,0,0,0,0,0,0,0,9,1,5,3,0,0,4,0,0,1)
data1 <- data.frame(id, SOG, stringsAsFactors=FALSE)
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