"variable that includes an integer"? A variable is either an integer or isn't. the
int(file.get_line()) method will return a type
int, which an
int variable can be set to.
Here's a sample to understand the different datatypes.
var line_text : String
var number : int
line_text = file.get_line() #gets the line as a string
number = int(line_text) #converts string into an int if the string only has characters 0-9