Append characters to string to make it fixed length

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I want to append some characters in start of an integer string. for eg my string is "45"
I want to append fourteen 0 before it like 0000000000000045.
The problem is,my string's length may vary, it can be of 4 characters, sometimes 3 or more then 10 characters.
I just want to make it 16 characters string,by appending 0 before it.
how can I do this?

What I have tried:

I am doing this

(my_string).PadLeft(16 , '0');

but it will fail if length is more then 10

Posted 4-Jul-17 2:31am

Syed Salman Raza Zaidi

Updated 4-Jul-17 3:12am

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Richard Deeming 4-Jul-17 8:36am

PadLeft works fine for me. If the string length is less than 16, it prepends enough 0's to make it exactly 16 characters. If the string length is greater than or equal to 16, it returns the string unchanged.

NB: PadLeft returns the modified string. It does not modify the original string. If you're not storing or using the returned value anywhere, you won't see the result.

Syed Salman Raza Zaidi 5-Jul-17 0:37am

I am storing it in a new string

2 solutions

Solution 2

e.g. number is an int of 45
and you want to have a string which is 16 characters long.

var number = 45;
var text = number.ToString("D16");

Please have a look at this
Standard Numeric Format Strings | Microsoft Docs[^]

Posted 4-Jul-17 3:12am

TheRealSteveJudge

Updated 4-Jul-17 3:22am

v4

Comments

Richard Deeming 4-Jul-17 9:18am

16 characters, not 16 bytes! :)

TheRealSteveJudge 4-Jul-17 9:22am

You're right. Thank you.

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OriginalGriff · Accepted Answer · 2017-07-04T03:10:00

Solution 1

In addition to PadLeft, it's worth keeping it as an integer number, and using ToString to "pad" it to the "full length" only when you want to present it to the user:

C#

int i = 45;
string padded = i.ToString("D16");

Posted 4-Jul-17 3:10am

OriginalGriff