To wrtie an array

Dear Sir/Madam

I am manipulating a received code in IDL.
in a line of it, this has written:

D_=[‘1’, ‘2’, ‘3’];
But when I run this line I encounter with this error: “syntax error”
I want to know what is the problem with that and how I could correct it. I know it should be a very simple error because I am a beginner but I think that I need your help.

It maybe be you are using the wrong quotes, so you are writing D_=[‘1’, ‘2’, ‘3’]; instead of the correct way without bended quotes: D_=['1', '2', '3'];

Thanks for your reply.
Maybe you are right. I will try it.