How to form the title of a page using data from a data file

[ironfish1000]

If I have a data file eg data.json containing:
json
{
"population": 2731571
}

and have a file index.md in the same folder, I know I can get eg
Population: {{ population }}
in the contents of index.md

But if I use this in front matter, eg:

---
title: "This city has a population of {{ population }}"
--- 

Then 11ty throws an error.

Is there any way for me to get data into front matter?

Thanks ahead of time for any help.

[sentience]

I believe what you're looking for is eleventyComputed: https://www.11ty.dev/docs/data-computed/#using-a-template-string

---
eleventyComputed:
  title: "This city has a population of {{ population }}"
---

[ironfish1000]

@sentience Thanks very much for your quick and very helpful reply - that is exactly what I was looking for and works like a charm!