How to use myString.PadLeft?

Question

Why doesn't this work ?

string myString = "test";
int i = myString.Length; // i = 4
myString.PadLeft(5, '_'); // "myString" is should be equal to "_test", but it still "test"
i = myString.Length; // i = 4 (should be 5)

Answer 1

Most string methods don't change string itself, but return new string, so use it like this:

myString = myString.PadLeft(5, '_');

EDIT: Ahh yes, all methods. I thought about methods that don't return string and somehow ended with not entirely true sentence.