Hello Zach,
Is there a pattern to where you want to place the character? In other words, is it always going after the second character (in the above example the 2 and the period are the first two characters), or is it always going to be after the decimal, etc?
There should be a way to split the string, concatenate it with the desired character, and then re-concatenate the string halves. It'll only work if there's a pattern though.
Thanks!
Rachel
Esri Support Services
Rachel Guttmacher
ArcGIS Online Technology Lead
Esri Support Services