从字符串C＃查找日期时间 [英] Finding datetime from a string C#

问题描述

说我有一个字符串，它看起来像这样D1011608201313

Say I got a string that looks like this D1011608201313

第一部分是随机字母和媒体的部分是格式化像DD / MM / YYYY和日期梯记录的ID。然而，第一部分可以非常随意

The first part is random letters and the medium part is a date formatted like dd/mm/yyyy and the ladder an id for a record. However the first part can be pretty much random

像[随机字符串] [日期时间] [ID]，我如何才能找到的日期时间的位置。 。随机字符串的长度，大约是4至8个字符

Like [Random String][DateTime][ID], how would I find the placement of the datetime. The length of the random string, is about 4 to 8 characters.

如果我能找到的日期时间，所以它应该是从那里直截了当：）

If I can find the datetime, it should be pretty straight forward from there :)

推荐答案

您可以使用这个表达式假设日期是在DDMMYYYY格式，日期是在今年一系列的1900年至2099年，但会有对于一些模糊的概率。我也更新这是基于关闭您的评论你的问题是，日期是从目前的月份。

You could use this RegEx supposing the date is in DDMMYYYY format, and the dates are in the year range of 1900-2099, but there will be some probability for ambiguity. I also updated this to be based off your comment in your question that the dates are from the current month.

public static void Main()
{ 
  // Leaves room for ambiguity if the random prefix or index suffix look 
  // like dates as well.
  var pattern = "((0[1-9]|[12][0-9]|3[01])(0[1-9]|1[012])((19|20)[0-9]{2}))";

  // Or, I see in your comment that the dates are from the current month. 
  // If so then this decreases the probability of a false match. You could
  // use the following pattern instead:
  var year =  DateTime.Today.Year;
  var month  = string.Format("{0:00}", DateTime.Today.Month);
  pattern = "((0[1-9]|[12][0-9]|3[01])(" + month + ")(" + year + "))";        

  var str = "D1011608201313";
  var matches = Regex.Matches(str, pattern);
  if (matches.Count == 0) return;

  var groups = matches[0].Groups;     
  int d, m, y;
  int.TryParse(groups[2].Value, out d);
  int.TryParse(groups[3].Value, out m);
  int.TryParse(groups[4].Value, out y);
  var date = new DateTime(y, m, d);
  Console.WriteLine(date);
}

的正则表达式（从使用RegexBuddy）的详细分解：

Detailed breakdown of the RegEx (from RegexBuddy):

((0[1-9]|[12][0-9]|3[01])(0[1-9]|1[012])((19|20)[0-9]{2}))

Match the regular expression below and capture its match into backreference number 1 «((0[1-9]|[12][0-9]|3[01])(0[1-9]|1[012])((19|20)[0-9]{2}))»
   Match the regular expression below and capture its match into backreference number 2 «(0[1-9]|[12][0-9]|3[01])»
      Match either the regular expression below (attempting the next alternative only if this one fails) «0[1-9]»
         Match the character "0" literally «0»
         Match a single character in the range between "1" and "9" «[1-9]»
      Or match regular expression number 2 below (attempting the next alternative only if this one fails) «[12][0-9]»
         Match a single character present in the list "12" «[12]»
         Match a single character in the range between "0" and "9" «[0-9]»
      Or match regular expression number 3 below (the entire group fails if this one fails to match) «3[01]»
         Match the character "3" literally «3»
         Match a single character present in the list "01" «[01]»
   Match the regular expression below and capture its match into backreference number 3 «(0[1-9]|1[012])»
      Match either the regular expression below (attempting the next alternative only if this one fails) «0[1-9]»
         Match the character "0" literally «0»
         Match a single character in the range between "1" and "9" «[1-9]»
      Or match regular expression number 2 below (the entire group fails if this one fails to match) «1[012]»
         Match the character "1" literally «1»
         Match a single character present in the list "012" «[012]»
   Match the regular expression below and capture its match into backreference number 4 «((19|20)[0-9]{2})»
      Match the regular expression below and capture its match into backreference number 5 «(19|20)»
         Match either the regular expression below (attempting the next alternative only if this one fails) «19»
            Match the characters "19" literally «19»
         Or match regular expression number 2 below (the entire group fails if this one fails to match) «20»
            Match the characters "20" literally «20»
      Match a single character in the range between "0" and "9" «[0-9]{2}»
         Exactly 2 times «{2}»

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