\def\licann#1{% #1 - lesson number with strings
\ctxlua{parsedate=thirddata.scancsv.ParseCSVLine('#1','n.º');%
local Nlic=(parsedate[2]);%
Nlic=tonumber(string.match(Nlic, '%d+'));%
context(Nlic ~=0 and 1 or 0)}}
\starttext
\licann{"lesson nº456Alterada"}
\stoptext
thanks in advance
Have a nice day
jorge