Parse Multiple Date Formats using RegEx in C#

c#, datetime, regex

Solution

You don't need Regex. You can use `DateTime.TryParseExact`

var dateValues = new[] { "04-2014", "April, 2014", "April,2014", "Invalid Date" };
var formats = new[] { "MM-yyyy","MMMM, yyyy","MMMM,yyyy" };

foreach (var s in dateValues)
{
    DateTime dt;
    if (DateTime.TryParseExact(s, formats, CultureInfo.InvariantCulture, DateTimeStyles.None, out dt) == false)
    {
        Console.WriteLine("Can not parse {0}", s);
    }
}

Problem

Using C# 4.5 I have a need to be able to accept dates in multiple string formats and need to be able to parse them them all into valid dates. Examples include: ``` 04-2014 April, 2014 April,2014 ``` I have come up with the following code that allows me to configure a dictionary with all the possible formats with their representative RegEx format and the .NET equivalent for `DateTime.ParseExact`. This solution works... however, there's a lot of `foreach` and `if` blocks and I just want to find out if there is a more elegant/clean/faster solution. ``` DateTime actualDate; var dateFormats = new Dictionary<string, string> { { @"\d{2}-\d{4}", "MM-yyyy" }, { @"(\w)+,\s\d{4}", "MMMM, yyyy" }, { @"(\w)+,\d{4}", "MMMM,yyyy" } }; var dateValues = new[] { "04-2014", "April, 2014", "April,2014", "Invalid Date" }; var successfulDateParse = false; foreach (var dateValue in dateValues) { foreach (var dateFormat in dateFormats) { var regex = new Regex(dateFormat.Key); var match = regex.Match(dateValue); if (match.Success) { actualDate = DateTime.ParseExact(match.Value, dateFormat.Value, CultureInfo.InvariantCulture); successfulDateParse = true; break; } } if (!successfulDateParse) { // Handle where the dateValue can't be parsed } // Do something with actualDate } ``` Any input is appreciated!

Original source