Convert an int to a string with leading zeros in C#
This article illustrates the different techniques to convert an int to a string that is padded with leading zeros to a specified length.
1. Using String.PadLeft() method
The standard way to convert an int to a string with leading zeros in C# is using the String.PadLeft() method. It returns a new string of a specified length, with the string left padded with spaces or the specified character. Here’s the working example, which uses the PadLeft() method to create a new 8-digit string from the given number padded with all zeros.
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using System; public class Example { public static void Main() { int number = 1111; string s = number.ToString().PadLeft(8, '0'); Console.WriteLine(s); // 00001111 } } |
2. Using Int32.ToString() method
Alternatively, you can use the Int32.ToString() method to convert a numeric value to its equivalent string representation. It is overloaded to accept a standard or custom numeric format string. The following example formats an Int32 value using the “D” format specifier with a precision specifier of 8:
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using System; public class Example { public static void Main() { int number = 1111; string s = number.ToString("D8"); Console.WriteLine(s); // 00001111 } } |
The following solution uses the “0” custom format specifier as a zero-placeholder symbol.
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using System; public class Example { public static void Main() { int number = 1111; string s = number.ToString("00000000"); Console.WriteLine(s); // 00001111 } } |
3. Using String.Format() method
Another option is to use the String.Format() method to pad a string with leading or trailing characters to a specified length. The following example formats an Int32 value using the “D” format specifier with a precision specifier of 8:
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using System; public class Example { public static void Main() { int number = 1111; string s = String.Format("{0:D8}", number); Console.WriteLine(s); // 00001111 } } |
You can also use the “0” custom format specifier, as shown below:
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using System; public class Example { public static void Main() { int number = 1111; string s = String.Format("{0:00000000}", number); Console.WriteLine(s); // 00001111 } } |
4. Using String Interpolation
Starting with C# 6.0, you can format your string using the String Interpolation ‘$’. It provides a more concise syntax to format strings, which is easier to read than traditional string formatting methods. With String Interpolation, the above code can be shortened to:
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using System; public class Example { public static void Main() { int number = 1111; string s = $"{number:D8}"; Console.WriteLine(s); // 00001111 } } |
Or, use the “0” custom format specifier:
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using System; public class Example { public static void Main() { int number = 1111; string s = $"{number:00000000}"; Console.WriteLine(s); // 00001111 } } |
That’s all about converting an int to a string with leading zeros in C#.
Thanks for reading.
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