Regular expression to validate version numbers

Question

I need a regular expression to validate version numbers.

I have 4 types of version number:

• 2015.1
• 2015.1.01
• 2015.1.01.1

• 2015.1.01.1.RE

• Group 1#: I need exactly 4 numbers

• Group 2#: exactly 1 number
• Group 3#: (1-2) numbers
• Group 4#: (1-4) numbers
• Group 5#: just RE

I already tried ^(\d+\.)?(\d+\.)?(\d+\.)?(\d+\.)?(\w+)$ but doesn't work.

string Expressao = @"^(\d+\.)?(\d+\.)?(\d+\.)?(\d+\.)?(\w+)$";
Regex Reg = new Regex(Expressao);
foreach(string rotulo in rotulos)
{
    Match result = Reg.Match(rotulo);
    if (result.Success)
    {
        Console.ForegroundColor = ConsoleColor.Green;
        Console.WriteLine(string.Format("Sucesso! {0}", rotulo), ConsoleColor.Green);
    }
    else
    {
        Console.ForegroundColor = ConsoleColor.Red;
        Console.WriteLine(string.Format("Falha! {0}", rotulo), ConsoleColor.Green);
    }
}
Console.ReadKey();

How can I do this?

Answer 1

Your regex must be,

string Expressao = @"^\d{4}\.\d(?:\.\d{1,2}(?:\.\d{1,4}(?:\.RE)?)?)?$";

DEMO

Answer 2

Let's start out with the basics.

First, list the five groups

1. [0-9]{4}
2. [0-9]
3. [0-9]{1,2}
4. [0-9]{1,4}
5. RE

Next, list the four variations

1. [0-9]{4}\\.[0-9]
2. [0-9]{4}\\.[0-9]\\.[0-9]{1,2}
3. [0-9]{4}\\.[0-9]\\.[0-9]{1,2}\\.[0-9]{1,4}
4. [0-9]{4}\\.[0-9]\\.[0-9]{1,2}\\.[0-9]{1,4}\\.RE

Finally, put them all together.

^([0-9]{4}\\.[0-9]|[0-9]{4}\\.[0-9]\\.[0-9]{1,2}|[0-9]{4}\\.[0-9]\\.[0-9]{1,2}\\.[0-9]{1,4}|[0-9]{4}\\.[0-9]\\.[0-9]{1,2}\\.[0-9]{1,4}\\.RE)$

This gives an working answer, but not a very nice one.

But knowing a little RE magic, you can create a nicer version. Here I linked optionals to chain together the full version.

^[0-9]{4}\\.[0-9](\\.[0-9]{1,2}(\\.[0-9]{1,4}(\\.RE)?)?)?$

Answer 3

If you are using c# then you can use Version.TryParse .

Sample:

string strVersion = "23.1.0";
if(Version.TryParse(strVersion, out Version version)
{
     // valid parsed.
}
else
{
    // invalid version.
}