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Parsing a Date Like "Wednesday 13th January 2010" with .NET

开发者 https://www.devze.com 2022-12-16 12:11 出处:网络
How can I convert the following strings to a System.DateTime object? Wednesday 13th January 2010 Thursday 21st January 2010

How can I convert the following strings to a System.DateTime object?

Wednesday 13th January 2010

Thursday 21st January 2010

Wednesday 3rd February 2010

Normally something like the following would do it

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DateTime dt;
DateTime.TryParseExact(value, "dddd d MMMM yyyy", DateTimeFormatInfo.InvariantInfo, DateTimeStyles.None, out dt);

but this doesn't work because of the 'th', 'st' or 'rd' in the string

Update

It appears that DateTime doesn't support formatting the 'th', 'st', 'rd' etc so they need to be stripped before parsing. Rubens Farias provides a nice regular expression below.


What about strip them?

string value = "Wednesday 13th January 2010";
DateTime dt;
DateTime.TryParseExact(
    Regex.Replace(value, @"(\w+ \d+)\w+ (\w+ \d+)", "$1 $2"),
    "dddd d MMMM yyyy", 
    DateTimeFormatInfo.InvariantInfo, 
    DateTimeStyles.None, out dt);


Another approach.

string sDate = "Wednesday 13th January 2010";
string[] sFields = sDate.Split (' ');
string day = sFields[1].Substring (0, (sFields[1].Length - 2));
DateTime date = new DateTime (sFields[3], sFields[2], day);


Another alternative using escape characters for handling (st, nd, rd, and th) without stripping them before the call of DateTime.TryParseExact

string dtstr = "Saturday 23rd January 2016";
DateTime dt;
string[] formats = new string[] { 
    "dddd d\\s\\t MMMM yyyy", "dddd d\\n\\d MMMM yyyy",
    "dddd d\\r\\d MMMM yyyy", "dddd d\\t\\h MMMM yyyy" };
bool result = DateTime.TryParseExact(dtstr, formats, CultureInfo.InvariantCulture, DateTimeStyles.None, out dt);


Where does "th", "st","nd" or "rd" appear below?

  • monday
  • tuesday
  • wednesday
  • thursday
  • friday
  • saturday
  • sunday

  • january

  • february
  • march
  • april
  • may
  • june
  • july
  • august
  • september
  • october
  • november
  • december

However you know those 4 will always be followed by a space. So unless I've missed something, a simple

value = value.Replace("August","Augus").Replace("nd ","").Replace("st ","").Replace("nd ","").Replace("rd ","").Replace("Augus","August");
DateTime dt;
DateTime.TryParseExact(value,"DDDD dd MMMM yyyy", DateTimeFormatInfo.InvariantInfo, DateTimeStyles.None, out dt);


No credit to me but this looks interesting for general DataTime parsing: http://www.codeproject.com/KB/datetime/date_time_parser_cs.aspx?msg=3299749


I remembered this post on using MGrammar to parse a lot of different ways to express dates and times. It doesn't exactly answer your question, but it might serve as a useful base depending on what your ultimate goal is.


Expanding on Kenny's approach, I added some code to pass integers to the DateTime variable...

string sDate = "Wednesday 13th January 2010";
string[] dateSplit = sDate.Split (' ');
string day = dateSplit[1].Substring(0, dateSplit[1].Length - 2);
int monthInDigit = DateTime.ParseExact(dateSplit[3], "MMMM", CultureInfo.InvariantCulture).Month;
DateTime date = new DateTime(Convert.ToInt16(year), monthInDigit, day);
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