UltiSnips snippet for automatic subscript

Question

I stole Gilles Castel's snippet for automatic subscript, and I tried to extend it to automatically subscript an i or j that follows any character. Here is my attempt

snippet '([A-Za-z])(?:\d|[ij])' "auto subscript" wrA
`!p snip.rv = match.group(1)`_`!p snip.rv = match.group(2)`
endsnippet

This throws

IndexError: no such group
Executed snippet code: 
  1 > snip.rv = match.group(2)
  2

I do not know any Python, but I am hoping that this isn't a very tricky issue to solve. Any help is appreciated. Thank you.

Answer 1

I believe the (?:...) makes the second sub-expression anonymous (you can't grab it with match.group).

I would try:

snippet '([A-Za-z])(\d|[ij])' "auto subscript" wrA
`!p snip.rv = match.group(1)`_`!p snip.rv = match.group(2)`
endsnippet