Need script to change index page numbers

> in case when there are some numbers in the text as well? 

That's true. But it's always a problem to figure out what the topic separator is. Could be an en-space, two spaces -- which are easy to find. Could also be a comma and a space, which is a problem because that's also the page-number separator. If you know the topic separator there's no need to split the index into two columns, you just take each paragraph from the separator to the end.

This particular script doesn't handle abbreviated page ranges very well. For instance, 28-9 incremented by 2 should be 30-31, but comes out as 30-11. So you'd have to unrange ranges, then do the adjustments, and re-range. But that, too, is a problem. For instance, 34-36, 37 -- it's simple enough to unrange this to 34, 35, 36, 37, then increment by 2 to 36, 37, 38, 39, but then when you're re-ranging you get 36-39. You don't know that 39 is out of the range.

So because there are that many problems with page numbers apart from deciding where they start, and because updating index numbers after the index was produced is an act of desperation, you just hope for the best and keep your fingers crossed. And checking manually later whether there are any numbers in the topic names, by the way, isn't a big deal.

What should be added to the script is also a maximum: now it has only one mode: greater than a number. It should also handle greater or smaller than a number.

Here a script to adjust numbers. You need to set the breakOff (the number from which to renumber) and by how much the numbers should be incremented (the value at diff). You can use a negative number to decrement page numbers. To do all numbers, use a break-off of 1.

Select a text frame or an insertion point to target a story.

(function () {
  var breakOff = 100;
  var diff = 2;
  var num;

  try {
    var story = app.selection[0].parentStory;
  } catch (_) {
    alert ('Select a text frame or a text object');
    exit();
  }

  app.findGrepPreferences = null;
  app.findGrepPreferences.findWhat = '\\d+';
  var pNums = story.findGrep();
  for (var i = pNums.length-1; i >= 0; i--) {
    num = Number (pNums[i].contents);
    if (num >= breakOff) {
      pNums[i].contents = String (num + diff);
    }
  }
}());

All page numbers or only those greater than a certain value?

Hi Tom:

For next book, it may be worth noting that InDesign can create an index for you. After you add the index markers, you can update it after edits and all the page numbers will update. https://helpx.adobe.com/indesign/using/creating-index.html

~Barb

You can do it in Excel or similar.