Best implementation for an isNumber(string) method

Question

In my limited experience, I\'ve been on several projects that have had some sort of string utility class with methods to determine if a given string is a number. The idea h

Answer 1

If absolute performance is key, and if you are just checking for integers (not floating point numbers) I suspect that iterating over each character in the string, returning false if you encounter something not in the range 0-9, will be fastest.

RegEx is a more general-purpose solution so will probably not perform as fast for that special case. A solution that throws an exception will have some extra overhead in that case. TryParse will be slightly slower if you don't actually care about the value of the number, just whether or not it is a number, since the conversion to a number must also take place.

For anything but an inner loop that's called many times, the differences between all of these options should be insignificant.