Selecting specific elements of a string

I'm working on a program that requires a certain sequence of outputting from a string. In python, I am able to use this line to select the last 2 elements of the string to be added to the first 2 elements of the string to form the output

sl=str(z1)

sll=sl[-2:]+sl[:2]

Any idea how to replicate this in teststand. 

Locals.hextstr=Str(Locals.y1,"%x"), Locals.hextstr2=Str(Locals.y2,"%x"),Locals.s=Locals.hextstr+Locals.hextstr2

I need to get the last 2 elements from hexstr and then to be followed by the first 2 elements of hexstr and repeat this for hexstr2 also