How to parse DateTime SubString out of variable String

Question

I have a String like this:

"WAIT_UNTIL;SYSTEM_TIME >= Di 15 Sep 2009    23:00:21 and IgnKeyPos ==3"

or something like this

"IF;Thermal >=20 and SYSTEM_TIME >= Tue 16 Sep 2009    23:00:21 "

I need to extract only the Time and Date part so I can use it later like this:

TimeThen = DateTime.Parse("Di 15 Sep 2009    23:00:21");

How should I start ?

Answer 1

This would match, although with more feedback on the expected format it could be enhanced. For now it accepts at least 1 space between the date/time parts.

string input = "IF;Thermal >=20 and SYSTEM_TIME >= Tue 15 Sep 2009    23:00:21 ";
string pattern = @"[A-Z]+\s+\d+\s+[A-Z]+\s+\d{4}\s+(?:\d+:){2}\d{2}";
Match match = Regex.Match(input, pattern, RegexOptions.IgnoreCase);

if (match.Success)
{
    string result = match.Value;
    DateTime parsedDateTime;
    if (DateTime.TryParse(result, out parsedDateTime))
    {
        // successful parse, date is now in parsedDateTime
        Console.WriteLine(parsedDateTime);
    }
    else
    {
        // parse failed, throw exception
    }
}
else
{
    // match not found, do something, throw exception
}

Answer 2

Consider using Regular Expressions

Here's some info on using them in C#:

• http://msdn.microsoft.com/en-us/library/ms228595(VS.80).aspx
• http://www.regular-expressions.info/dotnet.html

Here's a sample usage

Regex dateTimeRegex = new Regex("\w<=(?<ParsedDateTime>YOUR REGEX GOES HERE)");

if(match.Success && match.Groups["ParsedDateTime"].Success)
{
   string parsedDateTime = match.Groups["ParsedDateTime"].Value;

   // process your parsed value here
}

Answer 3

(?<trash>.*?)<?<arrow>\s\>\=\s)(?<dow>\w{2,3})\s*(?<day>\d{1,2})\s*(?<month>\w{3})\s*(?<time>\d{1,2}\:\d{1,2}\:\d{1,2}).*

像第一个这样的正则表达式？

Answer 4

private static DateTime ExtractDateTime(string format)
{
    int length = format.Length;
    for (int startIndex = 0; startIndex < length; startIndex++)
    {
        for(int subLength = length - startIndex; subLength > 0; subLength--)
        {
            string substring = format.Substring(startIndex, subLength);
            DateTime result;
            if (DateTime.TryParse(substring, out result))
            {
                return result;
            }
        }
    }
    return DateTime.MinValue;
}