Stack on index digits

Hello

I have an index vector I need to process and I want to introduce another digit in front of the current index but without summing them.

As an example say I got

Idx=[1 2 3 1 2 3 1 2 3] the value I want to add to this index say is "2"

Is there a way to create the following

IdxNew= [21 22 23 21 22 23 21 22 23]

(the values are not summed - is just the digit 2 is introduced in front of every previous digit)

Is there an easy way to stuck digits like that ?

Thank you in advance

Answer 1

[Sean de Wolski]

idx2 = str2num(regexprep(num2str(Idx),'([0-9]+)','2$1'))

But why do you want to do this? This sounds like there might be a better way around it.

[Dimitris M]

Yes probably I was just wanted something compact and it occurred to me this as an idea !

Anyway thank you !