I'll join the fun with:
['12','34','35','231'].join(', ')
EDIT:
"'#{['12','34','35','231'].join("', '")}'"
Some string interpolation to add the first and last single quote :P
> a = ['12','34','35','231']> a.map { |i| "'" + i.to_s + "'" }.join(",")=> "'12','34','35','231'"
try this code ['12','34','35','231']*","
['12','34','35','231']*","
will give you result "12,34,35,231"
I hope this is the result you, let me know