Remove 1 to the highest value of each pair of consecutive values while keeping the rest unaltered-CodePudding

I have this vector:

1 2 19 5 7 2 20 56 89 20 103 76 104

How can I remove 1 to the highest of each pair of consecutive values (in this case: 1-2, 19-20, 103-104), while maintaining the rest of the values unaltered?

1 1 19 5 7 1 19 56 89 19 103 76 103

Thanks!

CodePudding user response：

Sort the values, get the index for consecutive values, and remove 1:

x <- c(1, 2, 19, 5, 7, 2, 20, 56, 89, 20, 103, 76, 104)

sorted <- sort(x)
w <- sorted[which(diff(sorted) == 1)]   1
x[x %in% w] <- x[x %in% w] - 1
# [1]   1   1  19   5   7   1  19  56  89  19 103  76 103