Replacing changing pattern in a string with a new pattern

[icydash]

Hey guys.  So I'm trying to write a script that replaces footnote citations in one format with footnote citations in another format.

 

For example, the text will read:  "Then he went down the street.[1] That is where the police found him [2].  They immediately arrested him at the house. [3]"

 

And I would like the script to find the [ #] strings and replace them with {#} ... so that the string reads:

"Then he went down the street.{1} That is where the police found him {2}.  They immediately arrested him at the house. {3}"

 

Note that there will be double, and even tripple, digit footnotes, so the script has to be able to recognize [##] or [###] and replace the brackets with {} accordingly.

 

I'm not really sure how to do this, since the "pattern" is constantly changing depending on the number between the brackets.  Ideas?

 

Thanks!