HomeSYNOPSIS
result = string.val(s [, i [, j]])
DESCRIPTION
Returns the numerical value of the substring s[i],
s[i+1], ···, s[j].
The default value for i is 1;
the default value for j is the number of characters in s.
RETURN VALUE
On success, a numerical value. If the substring doesn't decode to a number, returns nil.
NOTES
Generic Lua already supports turning strings into numbers natively. The string.val() described here has two advantages over the built in type coercion:
- You can specify a substring easily without creating more garbage.
- The application will not terminate if the data cannot be converted to a number. You just get nil.
EXAMPLE
>
print(string.val("XX42YYYY", 3, 4)
42