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Editorial Team
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Asked: 2026-05-28T01:14:54+00:00

I have question about grouping data into specific categories. Generally, if I have a

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I have question about grouping data into specific categories.

Generally, if I have a factor variable, I would perform something like below to bucket/recode the data into a preferred pattern:

educ = NA
educ[educ2 %in% levels(educ2)[c(5,8)]] <- "HS or Some College"
educ[educ2 %in% levels(educ2)[2:3]] <- "College Degree"
educ[educ2 %in% levels(educ2)[c(4,6)]] <- "Advanced Degree" 
educ[educ2 %in% levels(educ2)[c(1,7,9)]] <- NA
educ = factor(educ)

However, I’m struggling with trying to regroup a factor variable, TIME, which has 10,000 + levels. The data is structured as follows:

> levels(wj$time)
    [1] "0:00:05"  "0:00:07"  "0:00:08"  "0:00:10"  "0:00:13"  "0:00:15"  "0:00:18"  "0:00:23"  "0:00:31"  "0:00:34"  "0:00:36" 
   [12] "0:00:39"  "0:00:41"  "0:00:47"  "0:00:48"  "0:00:54"  "0:00:55"  "0:00:56"  "0:00:59"  "0:01:01"  "0:01:02"  "0:01:03" 
   [23] "0:01:13"  "0:01:17"  "0:01:31"  "0:01:33"  "0:01:41"  "0:01:44"  "0:01:48"  "0:01:50"  "0:01:52"  "0:01:53"  "0:01:55" 
   [34] "0:02:08"  "0:02:12"  "0:02:13"  "0:02:21"  "0:02:26"  "0:02:27"  "0:02:30"  "0:02:32"  "0:02:33"  "0:02:36"  "0:02:37" 
   [45] "0:02:38"  "0:02:43"  "0:02:45"  "0:02:53"  "0:02:56"  "0:03:07"  "0:03:15"  "0:03:19"  "0:03:21"  "0:03:22"  "0:03:24" 
   [56] "0:03:30"  "0:03:36"  "0:03:39"  "0:03:41"  "0:03:49"  "0:03:56"  "0:03:59"  "0:04:02"  "0:04:04"  "0:04:07"  "0:04:10" 
   [67] "0:04:11"  "0:04:12"  "0:04:14"  "0:04:16"  "0:04:17"  "0:04:19"  "0:04:22"  "0:04:27"  "0:04:28"  "0:04:30"  "0:04:37" 
   [78] "0:04:39"  "0:04:41"  "0:04:49"  "0:04:51"  "0:04:52"  "0:04:53"  "0:04:54"  "0:05:05"  "0:05:06"  "0:05:20"  "0:05:22"

I’m just not sure how to quickly bucket the data into specific brackets when there are so many factor levels. I’d like to group them into perhaps 0:12:00 to 0:05:00 and 0:05:01 to 0:10:00 and so forth. With so many factor levels, I’m just a little lost on how to identify when to start and end bucketing. Can anyone provide any help? With 10,000 + buckets, this becomes an issue with how I would traditionally do things.

Thanks!

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1 Answer

  1. Editorial Team

    You can split the timestamp into its components: the buckets are then very easy to compute.

    # Sample data
n <- 10
d <- data.frame(
  time = paste( 
    sample(0:23, n, replace=TRUE), 
    sample(0:59, n, replace=TRUE), 
    sample(0:59, n, replace=TRUE), 
    sep=":" 
  ),
  value = rnorm(n)
)

# Split the "time" column into its components
d$time <- as.character( d$time )
times <- strsplit( d$time, ":" )
times <- lapply( times, as.numeric )
times <- do.call(rbind, times)
colnames(times) <- c("hour", "minute", "second")
d <- cbind(times, d)

# Build the buckets
d$bucket <- paste(
  sprintf( "%02d:%02d:00", d$hour, floor( d$minute / 5 ) * 5 ),
  sprintf( "%02d:%02d:59", d$hour, floor( d$minute / 5 ) * 5 + 4 ),
  sep=" to "
)
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