Using this dataset: dat <- read.table(textConnection("day noRes.Q wRes.Q 1 237074.41 215409.41 2 2336240.20 164835.16 3 84855.42 357062.72 4 76993.48 386326.78 5 73489.47 307144.09 6 70246.96 75885.75 7 69630.09 74054.33 8 66714.78 70071.80 9 122296.90 66579.08 10 63502.71 65811.37 11 63401.84 64795.12 12 63387.84 64401.14 13 63186.10 64163.95 14 63160.74 63468.25 15 60471.15 60719.15 16 58235.63 57655.14 17 58089.73 58061.34 18 57846.39 57357.89 19 57839.42 56495.69 20 57740.06 56219.97 21 58068.57 55810.91 22 58358.34 56437.81 23 76284.90 73722.92 24 105138.31 100729.00 25 147203.03 178079.38 26 109996.02 111113.95 27 91424.20 87391.56 28 89065.91 87196.69 29 86628.74 84809.07 30 79357.60 77555.62"),header=T)
I'm attempting to generate a column that continuously numbers consecutive rows where wRes.Q is greater than noRes.Q. To that end, I've come up with the following: dat$flg <- dat$wRes.Q>dat$noRes.Q dat$cnt <- with(dat, ave(integer(length(flg)), flg, FUN=seq_along)) The problem with dat$cnt is that it doesn't start over with 1 when a 'new' group of either true or false is encountered. Thus, row 9's cnt value should start over at 1, as should dat$cnt[10], and dat$cnt[11]==2, etc. (the desired result is shown below) In the larger dataset I'm working with (>6,000 rows), there are blocks of rows where the number of consecutive rows with dat$cnt==TRUE exceeds 100. My goal is to plot these blocks of rows as polygons in a time series plot. If, for the small example provided, the number of consecutive rows with dat$cnt==TRUE is greater than or equal to 5 (the 2 blocks of rows satisfying this criteria in this small example are rows 3-8 and 10-15), is there a way to add a column that uniquely numbers these blocks of rows? I'd like to end up with the following, which shows the correct "cnt" column and a column called "plygn" that is my ultimate goal: dat # day noRes.Q wRes.Q flg cnt plygn # 1 237074.41 215409.41 FALSE 1 NA # 2 2336240.20 164835.16 FALSE 2 NA # 3 84855.42 357062.72 TRUE 1 1 # 4 76993.48 386326.78 TRUE 2 1 # 5 73489.47 307144.09 TRUE 3 1 # 6 70246.96 75885.75 TRUE 4 1 # 7 69630.09 74054.33 TRUE 5 1 # 8 66714.78 70071.80 TRUE 6 1 # 9 122296.90 66579.08 FALSE 1 NA # 10 63502.71 65811.37 TRUE 1 2 # 11 63401.84 64795.12 TRUE 2 2 # 12 63387.84 64401.14 TRUE 3 2 # 13 63186.10 64163.95 TRUE 4 2 # 14 63160.74 63468.25 TRUE 5 2 # 15 60471.15 60719.15 TRUE 6 2 # 16 58235.63 57655.14 FALSE 1 NA # 17 58089.73 58061.34 FALSE 2 NA # 18 57846.39 57357.89 FALSE 3 NA # 19 57839.42 56495.69 FALSE 4 NA # 20 57740.06 56219.97 FALSE 5 NA # 21 58068.57 55810.91 FALSE 6 NA # 22 58358.34 56437.81 FALSE 7 NA # 23 76284.90 73722.92 FALSE 8 NA # 24 105138.31 100729.00 FALSE 9 NA # 25 147203.03 178079.38 TRUE 1 NA # 26 109996.02 111113.95 TRUE 2 NA # 27 91424.20 87391.56 FALSE 1 NA # 28 89065.91 87196.69 FALSE 2 NA # 29 86628.74 84809.07 FALSE 3 NA # 30 79357.60 77555.62 FALSE 4 NA Thanks, Eric [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.