How can a variable display the first character that's on the page?

Question

I'm creating a telephone directory and want each page to display the alphabet of the first listing on the page on the top - only one character.
Can you tell me how to do this?

Answer 1

Hmmmmm, seems I was wrong about the GREP styles. I just tried it and they don't get picked up. I consider that a bug, but it's probably "as designed."
That leaves you having to work with nested styles only, or Find/Change. I think what you'll need to do is redefine the Paragraph style so it has two nested styles that apply the correct style to whatever needs to be styled at the start of the paragraph, one for the first character and the second for the rest of the word(s) if you can figure out a trigger (can InData add an end nested style character or is thew some punctuation you can use?), then find/change to remove the applied character style. For that I'd serach for ^.+ with the find format set to the character style that InData applied and the chane format set to [None], which will only remove it from the beginning of your paragraphs. If this is done correctly there will be no change in appearance since the redefined paragraph style will do the formatting.
If that won't work, you can use find/change to apply a new style to the first characters. Search for ^. and set the change format to the new character style that you'll use in the variable. It needs to have the same attributes as the style applied by InData or the appearance will change.
The second method is probably easier since you don't need to redfine the paragraph style, but both methods require you to use find/change to alter the text, which means if more text is added you'll need to re-do the find/change. Not a big deal, but don't forget. I'd be tempted to wait until the last minute and just ignore the headers for the moment, if editing is ongoing. I'd also test this on a copy of the file for safety.