Thanks Rohit:
Figured it out on my own, but it wasn't obvious
In[216]:= numberOfButtons =
ToExpression@StringCases[ data[[ gln + 3]], DigitCharacter]
Out[216]= {2}
The following should have worked but didn't
In[217]:=
numberOfButtons[[1]] =
ToExpression@StringCases[ data[[ gln + 3]], DigitCharacter]
Out[217]= {2}
But this did
In[222]:= numberOfButtons[[1]]
Out[222]= 2
In[223]:= Head[numberOfButtons[[1]] ]
Out[223]= Integer
That seems pretty convoluted.
Once again, thanks for your help.