I am using an API that outputs dates in this format 20120314T130000 .
The date value is 13:00 14 March 2012. How can I parse a Date in this format to a .Net DateTime variable in C#?
Also what is this date format known as?
That's ISO 8601. The '-' separators are optional in this format.
You can't parse it with the normal DateTime.Parse method, but you can use ParseExact:
DateTime.ParseExact(date, "yyyyMMdd'T'HHmmss", CultureInfo.InvariantCulture)
If you have a mix of dates, some with separators and some without, you might need to use a regex to extract the relevant information and then construct the DateTime object.
Related
I have a program that do several things.
Two of them is read a date from a txt and rewrite a date in the same txt.
The read of the date is a regex expression like:
[0-9]{2}/[0-9]{2}/[0-9]{4} [0-9]{2}:[0-9]{2}:[0-5]{1}[0-9]{1})
The problem is that my regex expression only works in the format
"DD/MM/YYYY hh:mm:ss" and its impossible to make sure my regex expression can match all system datetime formats.
So, I need to make sure my program run's in every system, regardless the system datetime.now.
For that, i thought about format every system datetime.now, at start, to the format mentioned "DD/MM/YYYY hh:mm:ss".
At the moment i have the following code:
Datetime currentDate = DateTime.ParseExact(DateTime.Now.ToString(), "DD/MM/YYYY hh:mm:ss", CultureInfo.InvariantCulture);
However, when running some tests, using a system date in format "D/M/YYYY h:m:s" i get the error:
"String was not recognized as a valid DateTime."
The problem is that if my date, for example, is "9/27/2019 04:26:46"(M/D/YYYY h:m:s) it can't fit in the format i defined.
Any idea?
Thank you in advance!
You need to use the same format string and culture in every place where you convert the DateTime to string as well. In your sample code, you're doing
DateTime.Now.ToString()
This uses the default culture for the thread, and the default format. Unless assigned otherwise, the thread is probably using the local culture info. Instead, you would want to use the same format and the invariant culture:
DateTime.Now.ToString("dd/MM/yyyy HH:mm:ss", CultureInfo.InvariantCulture);
(note the lowercase "dd". "DD" is not a valid format specifier for date times; these things are case sensitive. Also note the "HH", which gives a 24-hour value, rather than 12-hour)
In practice, just using the invariant culture should be enough for persistence. Cultures already include default datetime formats, so unless you have a specific need to use a different format, why not use the default?
Also note that DateTime doesn't have a format. The format only comes into play when you convert from or to a string. That is the place where you need to ensure the same culture and format is used for both sides of the operation (and that's why for persistence, especially for data shared between different users or computers, you generally want to use the invariant culture).
If you need
to make sure my program run's in every system, regardless the system datetime.now
you can adapt international standard for this, say, ISO 8601.
In order to validate the DateTime, regular expressions like you have are not enough (just imagine leap years), but TryParse does it job:
string source = "2019-09-26T23:45:59";
// Either current culture date and time format or ISO
bool isValid = DateTime.TryParse(
source,
CultureInfo.InvariantCulture,
DateTimeStyles.AssumeLocal,
out var _date);
Or if you want to be more restrictive use TryParseExact:
// ISO only
bool isValid = DateTime.TryParseExact(
source,
"s",
CultureInfo.InvariantCulture,
DateTimeStyles.AssumeLocal,
out var _date);
If you want to represent DateTime.Now in ISO 8601, add "s" standard format string:
string dateAsString = DateTime.Now.ToString("s");
Alas, you can provide a bunch of formats which are able to cope with any date and time formats; a classical example of ambiguous date is
01/02/03 - 01 Feb 2003 (Russia)
01/02/03 - 02 Jan 2003 (USA)
01/02/03 - 03 Feb 2001 (China)
You can alleviate the problem, while providing several formats:
// Here we try to support 4 formats (note different delimeters)
string[] formats = new string[] {
"s", // try ISO first
"dd'.'MM'.'yyyy HH':'mm':'ss", // if failed try Russian
"MM'/'dd'/'yyyy HH':'mm':'ss", // on error have a look at USA
"yyyy'-'MM'-'dd HH':'mm':'ss", // the last hope is Chinese
};
bool isValid = DateTime.TryParse(
source,
formats,
CultureInfo.InvariantCulture,
DateTimeStyles.AssumeLocal,
out var date);
I have a windows service application in which I am getting the current date and time using DateTime.Now.ToString(), which returns '04-05-2018 05:50:12'.
But I tried the same in a sample console application, but it returns the date in a different format as '5/4/2018 5:51:32 AM'
Both these machines are being executed in the same machine. Can some one let me know why is there a date format difference in these applications?
The DateTime.ToString() formats the DateTime according to current culture. As Written in the Documentation
Converts the value of the current DateTime object to its equivalent
string representation using the formatting conventions of the current
culture.(Overrides ValueType.ToString().)
If you want the same string you should instead use the DateTime.ToString(string) overload and provide the exact format which you want.
The ToString(String) method returns the string representation of a
date and time value in a specific format that uses the formatting
conventions of the current culture; for more information, see
CultureInfo.CurrentCulture.
The format parameter should contain either a single format specifier
character (see Standard Date and Time Format Strings) or a custom
format pattern (see Custom Date and Time Format Strings) that defines
the format of the returned string. If format is null or an empty
string, the general format specifier, 'G', is used.
Some uses of this method include:
Getting a string that displays the date and time in the current
culture’s short date and time format. To do this, you use the “G”
format specifier.
Getting a string that contains only the month and year. To do this,
you use the “MM/yyyy” format string. The format string uses the
current culture’s date separator.
Getting a string that contains the date and time in a specific format.
For example, the “MM/dd/yyyyHH:mm” format string displays the date and
time string in a fixed format such as “19//03//2013 18:06". The format
string uses “/” as a fixed date separator regardless of
culture-specific settings.
Getting a date in a condensed format that could be used for
serializing a date string. For example, the "yyyyMMdd" format string
displays a four-digit year followed by a two-digit month and a
two-digit day with no date separator.
the string is 20131024174621 which is year =2013, month=10, date=24, hours=17, minutes=46, seconds=21
What I am trying to do is to convert and format it into 2013-10-24 17:46:21.
I have tried my luck as the code below however it return such error :
String was not recognized as a valid DateTime.
String timestamp = "20131024174621";
String converted = DateTime.Parse(timestamp).ToString("yyyy-MM-dd HH:mm:ss");
What should be the way of doing it right?
You have to use ParseExact.
void Main()
{
String timestamp = "20131024174621";
var date = DateTime.ParseExact(timestamp, "yyyyMMddHHmmss", CultureInfo.InvariantCulture);
Console.WriteLine (date.ToString("yyyy-MM-dd HH:mm:ss"));
}
Output:
2013-10-24 17:46:21
DateTime.ParseExact( timestamp, "yyyyMMddHHmmss", CultureInfo.InvariantCulture ).ToString( "yyyy-MM-dd HH:mm:ss" );
Since other two answer is correct, I want to point the root of your problem.
DateTime.Parse method uses Standard Date and Time Format Strings. From How Standard Format Strings Work
In a formatting operation, a standard format string is simply an alias
for a custom format string. The advantage of using an alias to refer
to a custom format string is that, although the alias remains
invariant, the custom format string itself can vary. This is important
because the string representations of date and time values typically
vary by culture. For example, the "d" standard format string indicates
that a date and time value is to be displayed using a short date
pattern. For the invariant culture, this pattern is "MM/dd/yyyy". For
the fr-FR culture, it is "dd/MM/yyyy". For the ja-JP culture, it is
"yyyy/MM/dd"
In 20131024174621 string, you need yyyyMMddHHmmss format for your current culture. Looks like your culture doesn't have this format and that's why you get this error.
For this kind of non-standart format string, you can use custom date format.
Any string that is not a standard date and time format string is
interpreted as a custom date and time format string.
As I wrote in third paragraph, this kind of date formats is based on culture. When you have this kind of custom date strings, in most case using DateTime.ParseExact Method (String, String, IFormatProvider) with specific culture is the best choice.
I tried converting 9/29/2013 2:44:28 PM (mm/dd/yyyy) to dd/mm/yyyy format.
I got a strange Date after Converting.
I tried
dateTimeVar.ToString("dd/mm/yyyy");
29/44/2013
The Date was a type of DateTime itself.
Lowercase mm means minutes, try this instead:
dateTimeVar.ToString("dd/MM/yyyy");
However, if this works depends on your local culture. If your current culture's date separator is different, / will be replaced with that. So if you want to enforce it use CultureInfo.InvariantCulture:
dateTimeVar.ToString("dd/MM/yyyy", CultureInfo.InvariantCulture);
MM is for months, mm is for minutes. That's why it gets your minutes (which is 44) instead of your month value.
Use it like;
dateTimeVar.ToString("dd/MM/yyyy");
Check out;
The "MM" Custom Format Specifier
The "mm" Custom Format Specifier
And remember, / has special meaning when you use it as a date separator. It replace itself with your current culture date separator. Forcing to use with InvariantCulture would be better.
dateTimeVar.ToString("dd/MM/yyyy", CultureInfo.InvariantCulture);
Take a look at;
The "/" Custom Format Specifier
What if I want to convert a string in dd/MM/yyyy to DateTime?
Then you can use DateTime.ParseExact method.
Converts the specified string representation of a date and time to its
DateTime equivalent using the specified format and culture-specific
format information. The format of the string representation must match
the specified format exactly.
As an example;
string s = "01/01/2013";
DateTime dt = DateTime.ParseExact(s, "dd/MM/yyyy", CultureInfo.InvariantCulture);
Console.WriteLine(dt);
Output will be;
1/1/2013 12:00:00 AM
Here a DEMO.
dateTimeVar.ToString("dd/mm/yyyy"); // Change to dd/MM/yyyy
The problem is mm stands for minute and you need MM which would be months
Tim's answer is correct, but to remove the format string altogether you can use. 'ToShortDateString'
DateTime date = DateTime.Today;
var stringDate = date.ToShortDateString();
var stringDate2 = date.ToString("dd/MM/yyyy");
Probably a simple question -
I'm reading in data from a number of files.
My problem is, that when I'm reading in the date from an american file, I parse it like so:
DateSold = DateTime.Parse(t.Date)
This parses the string t.Date into a date format, however it formats the american date to a european date, e.g.
If the date is in the file as 03/01/2011, it is read as the 3rd of January, 2011, when it should be the 1st of March 2011.
Is there a way of doing this so that it formats to the european date?
var dt = DateTime.ParseExact(t.Date, "MM/dd/yyyy", CultureInfo.InvariantCulture);
The DateTime itself has no formatting, it is only when you convert it to or from a string that the format is relevant.
To view your date with American format, you pass the format to the ToString method
string americanFormat = dt.ToString("MM/dd/yyyy");
If you are parsing the date from a file which is specifically a US formatted file then simply pass the US culture information into the parse function as follows;
var usCulture = "en-US";
var dateValue = DateTime.Parse(dateString, new CultureInfo(usCulture, false));
This way you can simply swap out the culture string per different region required for parsing. Also, you no longer have to research the specific datetime format nuances for each culture as .Net will take care of this for you as designed.
Use DateTime.ParseExact or DateTime.TryParseExact when parsing, and specify a format string when you format with ToString too.
Note that there's no such thing as "an American date" after it's been parsed. The DateTime value has no concept of formatting.
It sounds like you're not actually interested in the Parse part so much as the formatting part, e.g.
string formatted = dt.ToString("dd/MM/yyyy", CultureInfo.InvariantCulture);
... but I would recommend that you control both the parsing and formatting explicitly.
If you have different file formats, you'll need to give different format strings when you read each file. How you then format the data is a separate decision.
If you know the format ahead of time, you can use DateTime.ParseExact, using the American format as your format string.
string formatteddate=DateTime.Now.ToString("d") // output: 11/8/2012
string formatteddate=DateTime.Now.ToString("D") // output: Monday, November 08, 2012
string formatteddate=DateTime.Now.ToString("f") // output: Monday, November 08, 2012 3:39 PM
string formatteddate=DateTime.Now.ToString("g") // output: Monday, November 08, 2012 3:39:46 PM
string formatteddate=DateTime.Now.ToString("d") // output: 11/8/2012 3:39 PM
More date-time format in asp.net is given here.
http://dateformat.blogspot.in/2012/09/date-time-format-in-c-aspnet.html