There are some answers from 2016 here:
https://stackoverflow.com/questions/34636461/collapse-consecutive-runs-of-numbers-to-a-string-of-ranges
On 2025-02-21 7:59 p.m., Steven Ellis wrote:
Hi Dennis,
A quick Claude request:
"using r I have a sequence like: 1, 3, 4, 5, 7, 8, 12, 13, 14, 15,
20I would like to display it as: 1, 3-5, 7-8, 12-15, 20"
yielded:
condense_sequence <- function(nums) {
if (length(nums) == 0) return("")
if (length(nums) == 1) return(as.character(nums))
# Sort the numbers just in case they're not in order
nums <- sort(unique(nums))
# Initialize variables
ranges <- vector("character")
start <- nums[1]
prev <- nums[1]
for (i in 2:length(nums)) {
if (nums[i] != prev + 1) {
# End of a sequence
if (start == prev) {
ranges <- c(ranges, as.character(start))
} else {
ranges <- c(ranges, paste(start, prev, sep="-"))
}
start <- nums[i]
}
prev <- nums[i]
}
# Handle the last number or range
if (start == prev) {
ranges <- c(ranges, as.character(start))
} else {
ranges <- c(ranges, paste(start, prev, sep="-"))
}
# Join all ranges with commas
paste(ranges, collapse=", ")
}
# Your sequence
nums <- c(1, 3, 4, 5, 7, 8, 12, 13, 14, 15, 20)
# Apply the function
result <- condense_sequence(nums)
print(result)
# Output: "1, 3-5, 7-8, 12-15, 20"
Which appears to work well, though you may have other thoughts in mind /
edge cases this code does not cover.
Best,
Steven
On Fri, Feb 21, 2025 at 7:47 PM Dennis Fisher <fis...@plessthan.com> wrote:
R 4.4.0
OS X
Colleagues
I have a sequence like:
1, 3, 4, 5, 7, 8, 12, 13, 14, 15, 20
I would like to display it as:
1, 3-5, 7-8, 12-15, 20
Any simple ways to accomplish this?
Dennis
Dennis Fisher MD
P < (The "P Less Than" Company)
Phone / Fax: 1-866-PLessThan (1-866-753-7784)
www.PLessThan.com
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--
Dr. Benjamin Bolker
Professor, Mathematics & Statistics and Biology, McMaster University
Director, School of Computational Science and Engineering
> E-mail is sent at my convenience; I don't expect replies outside of
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______________________________________________
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