ZIP code regex
ZIP code (US postal code) regular expression can be used to verify if a given string contains a valid ZIP code or extract ZIP code from a string. Supports both 5-digit and 9-digit (ZIP+4) formats.
ZIP code regex
A regular expression to test a string against ZIP code format:
new Regex("^[0-9]{5}(?:-[0-9]{4})?$")
Enter a text in the input above to see the result
Example code in C#:
using System.Text.RegularExpressions;
using System.Linq;
using System;
public class Program
{
public static void Main()
{
// Validate ZIP code
Regex validateZipRegex = new Regex("^[0-9]{5}(?:-[0-9]{4})?$");
Console.WriteLine(validateZipRegex.IsMatch("word")); // prints True
// Extract ZIP code from a string
Regex extractZipRegex = new Regex("[0-9]{5}(?:-[0-9]{4})?");
string [] extracted = extractZipRegex.Matches("My zip code is 80001")
.Cast()
.Select(m => m.Value)
.ToArray();
Console.WriteLine(String.Join(",", extracted)); // prints 80001
}
}
Notes on ZIP code validation and extraction
This ZIP code regex has several limitations:
- It only works for US ZIP codes. If you need to support other countries, you might need to have a separate regular expression for each one of them and execute it based on the country provided.
- It can not guarantee that ZIP code actually exists. For instance, 99999 is a correct format, but this ZIP code does not exist.
- The extraction method can generate false-positive extraction if a string contains multiple numbers.
