C# equivalent of Substring & Patindex of Sql server

Question

I have the following SQL Server code which I would like to do in C# code. The logic is - to remove leading zeros please help me to translate the code into C#.

DECLARE @TESTVariable as varchar(500)
Set @TESTVariable = '00013025990'

SELECT Substring(@TESTVariable, Patindex('%[^0 ]%', @TESTVariable + ' '), Len(@TESTVariable))

output expected

input	output
'001'	'1'
'00'	'0'
'00013025990'	'13025990'

Answer 1

Rather than convert the T-SQL code directly to roughly .NET equivalents, consider using the String.TrimStart method for this task.

var TESTVariable = "00013025990";
Console.WriteLine(TESTVariable.TrimStart('0'));

I see from your edit you may have a zero value you want to preserve. If the string values are integers, you can use Parse and ToString to remove leading zeros except for the last:

Console.WriteLine(Int64.Parse("001").ToString("0"));
Console.WriteLine(Int64.Parse("00").ToString("0"));
Console.WriteLine(Int64.Parse("00013025990").ToString("0"));

Answer 2

1. String.TrimStart(Char) method is used to remove specified character from leading edge of the current string.

    string s= "00013025990"; var result = s.TrimStart('0');

2. or convert the string to a number so that the zeros are removed from the beginning (this method is correct for the zero character only)

    var result=int.Parse(s);

If you want to get '0' from '00' , the TrimStart is not correct and you have to use the second way.