c# - How can i format a string in c#

Question

I have a very simple Question to ask.

I have a string like:

         string str="89";

I want to format my string as follow :

         str="000089";

How can i achieve this?

`str="000089";` seems to do what you want... in the real code, is the 89 actually coming from another variable? — Marc Gravell, Mar 02 '18 at 10:51
no at all,as the number incerase the zero's from left replaced by the numbers.. like "000130" and "001457" — Mubsher Mughal, Mar 02 '18 at 10:52
I think you have nice answers below, but your question sounds like a duplicate of : https://stackoverflow.com/questions/12570807/format-string-to-a-3-digit-number — Florian, Mar 02 '18 at 11:02
Uuuugh! So sick of seeing high rep users answering poor questions that will very obviously have a dupe target. — Equalsk, Mar 02 '18 at 11:06

score 9 · Accepted Answer · answered Mar 02 '18 at 10:51

Assuming the 89 is actually coming from another variable, then simply:

    int i = 89;
    var str = i.ToString("000000");

Here the 0 in the ToString() is a "zero placeholder" as a custom format specifier; see https://learn.microsoft.com/en-us/dotnet/standard/base-types/custom-numeric-format-strings

Dmitry Bychenko · Answer 2 · 2018-03-02T11:02:26.230

6

If you have a string (not int) as the initial value and thus you want to pad it up to length 6, try PadLeft:

   string str = "89";

   str = str.PadLeft(6, '0');

edited Mar 02 '18 at 11:02

answered Mar 02 '18 at 10:54

Dmitry Bychenko

score 2 · Answer 3 · answered Mar 02 '18 at 10:53

2

If you want the input to be a string you'll have to parse it before you output it

int.Parse(str).ToString("000000")

answered Mar 02 '18 at 10:53

2

In *that* scenario (where `str` has the value), I suspect `str = str.PadLeft(6, '0');` would be more efficient – Marc Gravell Mar 02 '18 at 10:54
@MarcGravell I think so too – Mar 02 '18 at 10:58

3 Answers3