c# - Convert number in string to have certain number of digits

Question

I have a number in string format. This number will be between 1-6 digits and i need to convert it to be filled with zeroes on left side in order to always be 6 digit number. Is there any more efficient way than this?

Int32.Parse("5").ToString("D6")

Conversion to int just feels a bit unnecessary.

Answer 1

You could use String.PadLeft :

string result = number.PadLeft(6, '0');

If the number can be negative this doesn't work and you need your int.Parse approach.

Answer 2

这是不必要的

string result = "5".PadLeft(6,'0');

Answer 3

string someText = "test 5 rate";

someText = Regex.Replace(someText, @"\\d+", n => n.Value.PadLeft(5, '0'));