Get DateTime from a string

Question

I have some strings with DateTime and some without. I have to find out if each of strings contains DateTime.

Please help me with it.

String examples (in Russian):

13 сентября 2013 г., 11:27 пользователь  <support@example.com> написал:

13 сентября 2013 г., 11:29 пользователь Вячеслав Равдин <someone@example.com> написал:

13.09.2013, в 11:27, support@example.com написал(а):

What did you try? Can you show the code? What didn't work? Any errors? Exceptions? — Oded, Sep 13 '13 at 09:06
Possible help here : http://stackoverflow.com/questions/7854529/unable-to-parse-datetime-from-a-string — Atlasmaybe, Sep 13 '13 at 09:10

Roy Dictus · Answer 1 · 2013-09-13T09:16:38.557

1

You need to create a Regex for each of the patterns you want to recognize, then match the strings with each Regex until you have a match or until you have tried all Regexes.

public bool TryParseDate(string input, out DateTime result)
{
    if (MatchPattern1(input, result))
    {
       return true;
    }
    if (MatchPattern2(input, result)) 
    {
       return true;
    }
    ...
    return false;
}

where the MatchPattern methods each look for a particular Regex:

private bool MatchPattern1(string input, out DateTime result)
{
    Match match = Regex.Match(input, @"*pattern here*");
    if (match.Success)
    {
        result = *build date based on matches*;
        return true;
    }
    return false;
}

This way, you can do your matching however you want (with or without regular expressions) and make them as complicated as you want.

edited Sep 13 '13 at 09:16

answered Sep 13 '13 at 09:08

Roy Dictus

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2

Which will get the date portion of the string, but not parse it to a `DateTime` – Oded Sep 13 '13 at 09:09
@Oded, that's what the generic line `result = *build date based on matches*;` is for. – Roy Dictus Sep 13 '13 at 09:50
It is still overly generic IMHO ;) - it is akin to `result = *some magic happens here*` – Oded Sep 13 '13 at 09:51

Tim Schmelter · Answer 2 · 2013-09-13T09:47:54.833

You can use DateTime.TryParseExact with the russian culture and the proper format strings.

string russianLines = @"
13 сентября 2013 г., 11:27 пользователь написал:
13 сентября 2013 г., 11:29 пользователь Вячеслав Равдин написал:
13.09.2013, в 11:27, blablahblah...";

CultureInfo ruCult = CultureInfo.CreateSpecificCulture("ru-RU");
string[] formats = new[]{"dd MMMM yyyy", "dd.MM.yyyy"};
string[] lines = russianLines.Split(new[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
var lineDates = new List<DateTime?>();
foreach (string line in lines)
{
    string strDate = null;
    string[] tokens = line.Split(',');
    string[] parts = tokens.First().Split();
    if (parts.Length == 1)
        strDate = parts.First();
    else
        strDate = string.Join(" ", parts.Take(3));
    DateTime dt;
    if(DateTime.TryParseExact(strDate, formats, ruCult, DateTimeStyles.None, out dt))
        lineDates.Add(dt);
    else
        lineDates.Add(null);
}

Result in debugger:

[0] {13.09.2013 00:00:00}   System.DateTime?
[1] {13.09.2013 00:00:00}   System.DateTime?
[2] {13.09.2013 00:00:00}   System.DateTime?

Alyafey · Answer 3 · 2013-09-13T09:50:35.470

You can tray something like this

First

Change the Culture

 Thread.CurrentThread.CurrentUICulture = CultureInfo.GetCultureInfo("ru");
 Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture("ru");

Second

try Parsing your string

 private static DateTime ExtractDateTime(string str)
    {
        Thread.CurrentThread.CurrentUICulture = CultureInfo.GetCultureInfo("ru");
        Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture("ru");
        string[] date = str.Split(',');

        string[] needeedate = {""};

        needeedate[0] = date[0];
        for (var i = 1; i < date.Length; i++)
        {
            string[] temp1 = date[i].Split(' ');

            foreach (var temp in from s in temp1 where !String.IsNullOrEmpty(s) select needeedate[0] + " , " + s)
            {
                try
                {
                    var res = DateTime.Parse(temp);
                    needeedate[0] = temp;
                }
                catch (Exception)
                {
                    return DateTime.Parse(needeedate[0]);
                }
            }
        }

        return new DateTime();
    }

Example

string d = "13 сентября 2013 г., 11:27 пользователь  <support@example.com> написал:";

var ext = ExtractDateTime(d);

Get DateTime from a string

3 Answers3