How to parse custom string to DateTime C#? - c#

I need to parse to following Date Aug 20 11:38:43 2017 GMT
I'm trying to use DateTime.TryParseExact but can't find the correct format.
my latest format is MMM dd hh:mm:ss yyyy
my code :
string nextUpdate; //Next Update: Aug 20 11:38:43 2017 GMT
string dateTimeFormat = "MMM dd hh:mm:ss yyyy";
DateTime crldt;
DateTime.TryParseExact(nextUpdate.Split(':')[1].Trim(), dateTimeFormat, System.Globalization.CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None, out crldt);
when I run the code I get crldt ~ Date = {1/1/01 12:00:00 AM}
my question : what format should I use or what alternative way can I use to parse this string to DateTime
UPDATE
using suggestions from : #Sergey Berezovskiy
I've updated the code to :
string nextUpdate; // Next Update: Oct 7 06:16:18 2017 GMT
string dateTimeFormat = #"MMM dd HH:mm:ss yyyy \G\M\T";
Regex r =new Regex(".*Next Update:.*");
nextUpdate = r.Match(Crltext).Value;
DateTime crldt;
DateTime.TryParseExact(nextUpdate.Substring(nextUpdate.IndexOf(':')+1).Trim(),
dateTimeFormat, System.Globalization.CultureInfo.InvariantCulture,
System.Globalization.DateTimeStyles.AssumeUniversal, out crldt);
int intDTComp = DateTime.Compare(crldt, DT_now);
I've found a date that doesn't fit this format : Next Update: Oct 7 06:16:18 2017 GMT
what is the issue now ?
UPDATE 2
I've found the issue , but can't find a clean solution.
The issue is that the problematic date is Oct 7 ... ,
while the format is MMM dd ...
my workaround is adding another format MMM d hh:mm:ss yyyy and using it if date = {1/1/01 12:00:00 AM}
what other solution may I use in this scenario


First of all, don't forget that your string contains "GMT". You should either remove it from the string, or add to format pattern:
string nextUpdate = "Next Update: Aug 20 11:38:43 2017 GMT";
string format = #"MMM dd hh:mm:ss yyyy \G\M\T";
Next - don't split input string by : because there is another : symbols in the string. And you will get array with parts ["Next Update", " Aug 20 11", "38", "43 2017 GMT"]. Taking the second item from array gives you " Aug 20 11". Instead, you should just take substring after first : occurance:
string s = nextUpdate.Substring(nextUpdate.IndexOf(':') + 1).Trim();
And finally parse that string using your format:
IFormatProvider provider = CultureInfo.InvariantCulture;
DateTime date = DateTime.ParseExact(s, format, provider, DateTimeStyles.AssumeUniversal);
Output will depend on your time zone. E.g. for my time zone GMT+3 it will be:
8/20/2017 14:38:43


If this is your string:
"Next Update: Aug 20 11:38:43 2017 GMT"
Then when you do this:
nextUpdate.Split(':')[1].Trim()
You get this:
"Aug 20 11"
Which doesn't match your date format. I suspect you don't just want the second split value, but also all remaining split values. You can re-join them. Something like this:
string.Join(":", nextUpdate.Split(':').Skip(1)).Trim()
This would split them by the ":" character, skip the first one but keep all remaining ones, and re-join the remaining ones into another string with the ":" character again.
Note: You may also need to account for that time zone value. There are some helpful ideas on this question for how to do that.


If that's the input, I propose that you take the format exactly as the input
string nextUpdate = "Next Update: Aug 20 11:38:43 2017 GMT";
string dateTimeFormat = #"\N\e\x\t\ \U\p\d\a\t\e\:\ MMM dd hh:mm:ss yyyy\ \G\M\T";
DateTime crldt;
crldt = DateTime.ParseExact(nextUpdate, dateTimeFormat , System.Globalization.CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None);
This way, when reading the code it's very clear what the expected format is, and you don't have code with Split() or other items that need explanation.
Also note that if you leave the colons (:) like that, they may be replaced by .NET to match the hour separator. Use \: if you always require a literal colon.
As I wrote in the comments before, note that you're ignoring the time zone.


Use following code
CultureInfo provider = CultureInfo.InvariantCulture;
DateTime givenDate = DateTime.ParseExact("Aug 20 14:38:43 2017 GMT", "MMM dd HH:mm:ss yyyy GMT", provider); // here HH is for 24 hour format . use hh for 12 hour format
string expectedDate = givenDate.ToString("dd/MM/yy hh:mm:ss tt"); // tt is for AM or PM (no need to use tt if you use hour as HH I mean 24 hour format)
Your Output will be 20/08/17 11:38:43 AM

Related

How to convert datetime format in c#?

I want to convert the DateTime format using c#. This is my code
string date = "Thu May 20 2021 00:00:00 GMT-0700 (Pacific Daylight Time)";
var s = DateTime.ParseExact(date, "dd-MM-yyyy HH:mm:ss", null);
But this code not working the exception is 'System.FormatException: 'String was not recognized as a valid DateTime.'

The format you provide must match with the format used in the string. Hence the name ParseExact. After playing around a bit I was able to match these:
string date = "Thu May 20 2021 00:00:00 GMT-0700"
var s = DateTime.ParseExact(date, "ddd MMM dd yyyy HH:mm:ss \"GMT\"zzz", null);
You may need to manually truncate the (Pacific Daylight Time) or include it in the format as a literal (like I did with GMT here).
For more information you can work with DateTime format specifiers

Your format string means that the date value must be something like that:
string date = "20-05-2021 12:00:00";
var s = DateTime.ParseExact(date, "dd-MM-yyyy HH:mm:ss", null);
Try to use an other date value or change the date format string.
You can find a lot of good examples here:
https://learn.microsoft.com/en-us/dotnet/api/system.datetime.parseexact?view=net-5.0#System_DateTime_ParseExact_System_String_System_String_System_IFormatProvider_

What's the format date Node js (new date()) on C# [duplicate]

I have date object in JavaScript which give me: "Wed Oct 01 2014 00:00:00 GMT+0200";
I try to parse it but I get an exception:
string Date = "Wed Oct 01 2014 00:00:00 GMT+0200";
DateTiem d = DateTime.ParseExact(Date,
"ddd MM dd yyyy HH:mm:ss GMTzzzzz",
CultureInfo.InvariantCulture);

MM format specifier is 2 digit month number from 01 to 12.
You need to use MMM format specifier instead for abbreviated name of month.
And for your +0200 part, you need to use K format specifier which has time zone information instead of zzzzz.
And you need to use single quotes for your GMT part as 'GMT' to specify it as literal string delimiter.
string s = "Wed Oct 01 2014 00:00:00 GMT+0200";
DateTime dt;
if(DateTime.TryParseExact(s, "ddd MMM dd yyyy HH:mm:ss 'GMT'K",
CultureInfo.InvariantCulture,
DateTimeStyles.None, out dt))
{
Console.WriteLine(dt);
}
Any z format specifier is not recommended with DateTime parsing. Because they represents signed offset of local time zone UTC value and this specifier doesn't effect DateTime.Kind property. And DateTime doesn't keep any offset value.
That's why this specifier fits with DateTimeOffset parsing instead.

Date Formatting C#

I am having an issue converting this date format into another format. I was hoping that somebody on here would be able to help me out.
Here is my code:
string fromFormat = "ddd, dd MM yyyy HH:mm:ss zzz";
string toFormat = "yyyy-MM-dd";
DateTime newDate = DateTime.ParseExact("Mon, 25 03 2013 00:00:00 GMT", fromFormat, null);
Console.WriteLine(newDate.ToString(toFormat));
-------EDIT--------
I was able to get rid of my errors by changing the day from 22 to 25. My new issue is trying to get the timezone to convert from GMT to EST. Would anyone have any ideas?
-------EDIT #2-------
Here is my current code as it stands. I am still having issues with a timezone conversion.
var date = "Mon, 25 03 2013 00:00:00 GMT";
// Cuts off "GMT" portion of string
string newdate = date.Substring(0, 24);
// Switches the output of date
string fromFormat = "ddd, dd MM yyyy HH:mm:ss";
string toFormat = "yyyy-MM-dd";
DateTime newDate = DateTime.ParseExact(newdate, fromFormat, null);
string finaldate = newDate.ToString(toFormat);
// Output final date
Console.WriteLine(finaldate);
-------EDIT #3-------
The code:
var input = "Mon, 25 03 2013 00:00:00 GMT";
var inner = input.Substring(0, 24);
var format = "ddd, dd MM yyyy HH:mm:ss";
var zoneId = "Eastern Standard Time";
var parsed = DateTime.ParseExact(inner, format, CultureInfo.InvariantCulture);
var utcDateTime = DateTime.SpecifyKind(parsed, DateTimeKind.Utc);
var eastern = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(utcDateTime, zoneId);
Console.WriteLine(eastern);
The error:
Unhandled Exception: System.TimeZoneNotFoundException: Exception of type
'System.TimeZoneNotFoundException' was thrown.
at System.TimeZoneInfo.FindSystemTimeZoneByFileName (System.String id, System.String
filepath) [0x00000] in :0
at System.TimeZoneInfo.FindSystemTimeZoneById (System.String id) [0x00000] in :0
at System.TimeZoneInfo.ConvertTimeBySystemTimeZoneId (DateTime dateTime, System.String
destinationTimeZoneId) [0x00000] in :0
at Program.Main () [0x00000] in :0
Any help would be much appreciated! Thanks!
-------FINAL EDIT-------
This is what ended up changing the timezone and converting to the format that I needed. Special thanks to #MattJohnson for all of his help!
// Cuts off 'GMT' portion of string
var newdate = date.Substring(0, 24);
var fromFormat = "ddd, dd MM yyyy HH:mm:ss";
var toFormat = "yyyy-MM-dd";
var zoneId = "Eastern Standard Time";
var parsed = DateTime.ParseExact(newdate, fromFormat, CultureInfo.InvariantCulture);
// Specifies UTC time and converts it to EST timezone
var utcDateTime = DateTime.SpecifyKind(parsed, DateTimeKind.Utc);
var eastern = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(utcDateTime, zoneId);
// Converts date to final format needed
var finaldate = eastern.ToString(toFormat);

string fromFormat = "ddd, dd MM yyyy HH:mm:ss zzz";
The error is your zzz, it is expecting the numerical representation of the timezone, not the abbreviation of the timezone.
So a acceptable version would be
DateTime newDate = DateTime.ParseExact("Mon, 22 03 2013 00:00:00 +0:00", fromFormat, null);
but that would throw a different FormatExecption with the message "String was not recognized as a valid DateTime because the day of week was incorrect." If you make the Monday to Friday correction the parse works
DateTime newDate = DateTime.ParseExact("Fri, 22 03 2013 00:00:00 +0:00", fromFormat, null);
I don't think there is a format specifier that can take in the textual abbreviation version of the timezone.

As others pointed out, the input value you have is self-inconsistent. It refers to a March 22 2013 as a Monday when it is actually a Friday. So you should go back to your source data and figure out why that happens. I'm sure you have heard the saying, "Garbage In, Garbage Out".
If you are sure you want to ignore the day of week, and you are certain that the time zone will always be GMT, then you can do this:
var input = "Mon, 22 03 2013 00:00:00 GMT";
var inner = input.Substring(5, 19);
var format = "dd MM yyyy HH:mm:ss";
var parsed = DateTime.ParseExact(inner, format, CultureInfo.InvariantCulture);
var utcDateTime = DateTime.SpecifyKind(parsed, DateTimeKind.Utc);
Note that I explicitly set the kind to UTC, because you are bringing in GMT values. GMT and UTC are identical for all practical purposes.
If it's possible that other time zone values will be passed, then please provide a sampling of different possible inputs and perhaps we can find a way to accommodate that.
As an aside - this string looks very similar to RFC822/RFC1123 formatted dates, except you are passing the month as a number instead of one of the three-letter abbreviations. Did you do this intentionally? If so, you have broken the spec for this format. If your intention was to remove potentially localizable strings from the data, then please use a format that is already designed for that, such as ISO8601/RFC3339.
On Time Zones
You said you want to convert to EST, You probably mean "US Eastern Time", which alternates between EST and EDT for daylight saving time. Despite this, the Windows Time Zone database uses the id of "Eastern Standard Time" to refer to both values - so try not to get confused on that point.
Once you have the date as a DateTime of Utc kind, as I showed above, you can convert that to Eastern Time with the following:
var zoneId = "Eastern Standard Time"; // don't get confused here! :)
var eastern = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(utcDateTime, zoneId);
Just be careful what you do with this value. If you are displaying it to an user, then you are ok. Just do this:
var s = eastern.ToString("g"); // or whatever format you want.
But if you do math with this, or store it as an recorded event time, you are potentially introducing errors into your results. This is due to daylight saving time transitions. One way to avoid this is to use a DateTimeOffset type instead:
var utcDateTimeOffset = new DateTimeOffset(utcDateTime, TimeSpan.Zero);
var eastern = TimeZoneInfo.ConvertTimeBySystemTimeZoneId(utcDateTimeOffset, zoneId);
Now when you work with these values, any ambiguities are captured by the offset.
If this seems very confusing to you, don't worry - you're not alone. You might want to try using Noda Time instead. It will prevent you from shooting yourself in the foot.

To see what's wrong, print a DateTime using your fromString:
DateTime dt = new DateTime(2013, 3, 22);
string s = dt.ToString(fromFormat);
you'll see that the output is:
Fri, 22 03 2013 00:00:00 -04:00
so that is the format it would be expecting.
You might be able to get some help on the abbreviations from this article.

There are two issues:
1) The day selected was a Friday not a Monday
2) The 'zzz' wants a plus or minus 0:00
So, to get it to work would be:
string fromFormat = "ddd, dd MM yyyy HH:mm:ss zzz";
string toFormat = "yyyy-MM-dd";
DateTime newDate = DateTime.ParseExact("Fri, 22 03 2013 00:00:00 +0:00", fromFormat, null);
Console.WriteLine(newDate.ToString(toFormat));

There's no simple, built-in way to convert from a Time Zone abbreviation to an offset or proper name. This is discussed in this topic here:
Timezone Abbreviations
You'll either need to create a table of the abbreviations you want to use, mapped to an offset or proper name, or you'll need to change the format of your incoming date/time string to use offsets.

string fromFormat = "ddd, dd MM yyyy HH:mm:ss zzz";
string toFormat = "yyyy-MM-dd";
DateTime newDate = DateTime.ParseExact("Mon, 22 03 2013 00:00:00 +00:00", fromFormat, null);
Console.WriteLine(newDate.ToString(toFormat));

22 03 2013 00:00:00 GMT is not Monday it's Friday
try
string fromFormat = "ddd, dd MM yyyy HH:mm:ss zzz";
string toFormat = "yyyy-MM-dd";
Console.WriteLine(DateTime.ParseExact("Fri, 22 03 2013 00:00:00 +00:00", fromFormat,
CultureInfo.InvariantCulture).ToString(toFormat));

C# DateTime ParseExact exception

I'm having problems with DateTime.ParseExact method which is throwing exceptions that my input string is not in correct format.
Code follows :
class Program
{
static void Main(string[] args)
{
var rawDate = "Thu, 08 nov 2012 15:19:18 0";
var _format = "ddd, dd MMM yyyy HH:mm:ss K";
var date = DateTime.ParseExact(rawDate, _format, CultureInfo.InvariantCulture);
}
}
I found a few similar threads here on SO with exact date format and nobody reports any problem there.
I followed this as my guide :
ddd = Three letter Day of week
MMM = Three letter month
dd = Two digit day of month 01-31 (use "d" for 1-31)
HH = Hours using 24-hour clock. 00-24 (use "H" for 0-24)
mm = Minutes. 00-59
ss = Seconds. 00-59
K = Time zone information
yyyy = 4-digit year
What can be cause of exceptions?
Thank you in advance!

I think your 'K' might be a bit off.
The link here might give an explanation: http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx#KSpecifier
You can leave this blank and drop the 0 - K

You timezone is wrong in your input string - it needs to be in the format +00:00.
To test your datetime format strings, run them in reverse:
Console.WriteLine(DateTime.Now.ToString(_format));
which gives
Thu, 08 Nov 2012 15:50:58 +00:00

Time zone information looks like the most likely suspect to me.

Try this:
var _format = "ddd, dd MMM yyyy HH:mm:ss 0";
You will lose the timezone information, though.

Can this date be converted automatically?

I know that C# has some great date conversion tools. What I'm I'm wondering is if I can automatically convert this string to a date object:
"Fri May 11 00:00:00 EDT 2012"
I'm thinking I'll have to manually parse the month, day, and year but I'm hoping there is an easier way built-in. Any help would be appreciated.
Thanks!

You can use DateTime.ParseExact or DateTime.TryPraseExact to provide a custom format:
DateTime result;
if (!DateTime.TryParseExact(
"Fri May 11 00:00:00 EDT 2012",
"ddd MMM dd HH:mm:ss EDT yyyy",
CultureInfo.InvariantCulture,
DateTimeStyles.None,
out result)) {
// handle invalid date
}
All of the format options are listed on the Custom Date and Time Format Strings page on MSDN.

Convert.ToDateTime("Fri May 11 00:00:00 EDT 2012") should work just fine.

http://msdn.microsoft.com/en-us/library/xhz1w05e.aspx
Take a look at that. Should help you out.
Example:
// Convert a string returned by DateTime.ToString("R").
String dateString = "Sat, 10 May 2008 14:32:17 GMT";
ConvertToDateTime(dateString);

Yes, you can parse the string into a DateTime object :
String format = "ddd MMM dd hh:mm:ss EDT yyyy";
String dateString = "Fri May 11 00:00:00 EDT 2012";
DateTime result = DateTime.ParseExact(dateString, format, CultureInfo.InvariantCulture);

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