How to create C# correct string filter by regexp

Question

Have the problem with regexp on C#. I get the list of strings (names of directory) by Directory.GetDirectories. For example:

E:\DevArea\SandBox\1122334455
E:\DevArea\SandBox\1231231231
E:\DevArea\SandBox\1231231232
E:\DevArea\SandBox\1231231233
E:\DevArea\SandBox\1231231234
E:\DevArea\SandBox\123123123123
E:\DevArea\SandBox\1231231231ddd

I need to find directories names witch consists of only 10 digits (only 10). I tried to use next:

public List<string> GetDirectoryList()
{
    var directoryList = new List<string>();
    var list = Directory.GetDirectories(sourcePath);
    foreach (var field in list)
    {
        if (checker.CheckInfo(field.Substring(field.LastIndexOf('\\') + 1)))
        {
            directoryList.Add(field);
        }
    }
    return directoryList;
}

public bool CheckInfo(string checkingInfo)
{
    string stringPattern = "[0-9]{10}";

    if (!Regex.IsMatch(checkingInfo, stringPattern))
    {
        return false;
    }

    return true;
}

As result i had list of directories names witch consist of digits, but there were the next one:

E:\DevArea\SandBox\123123123123

How can i ignore names with more than 10 digit?

Since you strip off the parent directories you can just add anchors to the regex ^\d{10}$ — juharr
– juharr, Commented Dec 3, 2019 at 21:18
Thanks a lot! (?<!\d)[0-9]{10}(?!\d) - is the best for my case! — Alex P.
– Alex P., Commented Dec 3, 2019 at 21:47

Alex P. · Accepted Answer · 2019-12-04 08:15:03Z

1

It is better to do this in my case, i think:

public List<string> GetDirectoryList()
{
var directoryList = new List<string>();
var list = Directory.GetDirectories(sourcePath);
string stringPattern = "(?<!\d)[0-9]{10}(?!\d)";

foreach (var field in list)
{
    if (Regex.IsMatch(checkingInfo, stringPattern))
    {
        directoryList.Add(field);
    }
}
return directoryList;
}

Thanks for ctwheels!

edited Dec 4, 2019 at 8:15

answered Dec 4, 2019 at 6:49

Alex P.

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Comments

Olivier Martial Soro · Accepted Answer · 2019-12-04 21:04:37Z

0

Just do it:

    public bool CheckInfo(string checkingInfo)
    {
        return Regex.IsMatch(checkingInfo, "^[0-9]{10}$");
    }

edited Dec 4, 2019 at 21:04

answered Dec 3, 2019 at 21:54

Olivier Martial Soro

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