Check for and combine overlapping ranges

Question

How can I check if ranges overlap other ranges and combine the ones that do?

Example:

10-1000,15-350,50-1500,2100,1700-1800,45,40,145,2-1300

The result I want is:

2-1500,1700-1800,2100

I tried to make a plan on how to code it but it's getting me nowhere. Is there a useful package that I can use? Or if not what should my approach be?

Answer 1

Using sort and awk:

tr , '\n' | sort -n | awk '
BEGIN {
  FS = OFS = "-"
}
NF == 1 {
  $2 = $1
}
$2 <= end {
  next
}
$1 <= end {
  end = $2
  next
}
{
  emit()
  start = $1
  end = $2
}
END {
  emit()
}
function emit() {
  if (NR != 1) {
    if (start == end)
      print start
    else
      print start, end
  }
}' | paste -sd,

$ sh ./merge.sh <<<10-1000,15-350,50-1500,2100,1700-1800,45,40,145,2-1300
2-1500,1700-1800,2100