How to get the remaining letters of a variable

[Giang Dao]

I have some variables named "x2000" "yz2001"... I want to transform them to "2000x", "2001yz"...

I used function "substr" first to get the years. Then I want to put these years in front of the letters that remain in the name of variables ("x", "yz",...).

I do not know how to get this remaining part. I tried the code below but it did not work.

foreach v of varlist _all {
           local new = substr("`v'", -4, 4)
           local old = `v'-`new'
           rename `v' `new'`v'
           }

Many thanks for your help.

[Nick Cox]

2000x would be an illegal variable name. Variable names must start with a letter or an underscore. Your names are good; you probably need to reshape the data, however.

[Giang Dao]

Oh I see. I actually reshaped data before, to have the new variables with all years after them. What I want now is to have another "reshape" to have only the years in the first row of the table, and all the remain such as "x" or "yz" should become a column. It seemed to me that I am going to do "reshape long" with j as "x", "yz",... and 2000, 2001,... as new variables. Of course as you said they are numbers and can not be variables, so I guess I must do some other way...