Convert string to number?

[tin3tin]

I bet there is a trivial solution to this, but how do I convert a string to a number(int)?
I would have guessed that something along these lines would work:
colorbars()
Subtitle(sting(int("100")))
I'm trying to pass an imported text file and want to extract the numbers from the string, at a certain position, if those characters are numbers:
if ( LeftStr(LINE,3)==string(int(LeftStr(LINE,3))) ) { # A new clip is defined by a number first in the line ex. 001

[Guest]

Value("100")

[tin3tin]

Thank you. I could't see that function in the manual between the String functions or the Numeric functions, but now I see it among the Conversion functions... why I didn't look there... I do not know... Thank you again!