Question: This is the code (corona SDK btw), it is calling a physicsdata (unimportant). 

```
 r = math.random(1,5)
local scaleFactor = 1.0
local physicsData = (require "retro").physicsData(scaleFactor)
physics.addBody( enemy, physicsData:get(r) )

```

The r in 

```
 physicsData:get(r) )

```

has to be inside speech marks to work (I tested).

how can the r variable be string-ilised? ( :D )

Answer: 
If you need a string,

```
tostring(r)

```

For example, 

```
physics.addBody( enemy, physicsData:get(tostring(r)) )

```

If you really need quotes in the string (I doubt you do):

```
physics.addBody( enemy, physicsData:get('"' .. tostring(r) .. '"') )

```
What you want is to [concatenate](http://en.wikipedia.org/wiki/Concatenation) the strings. In Lua the concatenate operator is .. so you need to write something like:

```
"The value of the variable is "..var

```