QDateTime Conversion - qt

I need to convert the String variable to QDateTime format
my code looks
QString date ="Thu Jun 18 2015";
QDateTime tmp = QDateTime::fromString(date,"ddd MMM dd yyyy HH:mm:ss");
But the result is Thu Jan 1 00:00:00 1970.
Later I have to convert this date in to foramt yyyy-MM-dd HH:mm:ss, so as a first step I have convert the string in to QDateTime then I have to convert to the final format, is there anything mistake with the above code?
Any help will be appreciated.
Thanks
Haris

Your date string does not include a time, while you mentioned that you want one, this will fail at least in Qt 5.4 .
I don't know though why you get the epoche outputed, maybe that is dependant on your Qt version.
Your date format is also locale dependent.
See for example the doucmentation for "ddd" in QDateTime::fromString:
the abbreviated localized day name (e.g. 'Mon' to 'Sun'). Uses QDate::shortDayName().
Which unfortunately is not that clear, while it is more clear for QDateTime::toString:
the abbreviated localized day name (e.g. 'Mon' to 'Sun'). Uses the system locale to localize the name, i.e. QLocale::system().
For example, in my locale (German, Austria) "ddd" for Thursday results in "Do." which is different from "Thu" and makes it impossible to parse English abbrevations with that locale.
To ensure you are using the correct locale when reading or writing locale dependent output use QLocale.
In your case that would be QLocale::toDateTime:
QLocale locale(QLocale::English, QLocale::UnitedStates);
QDateTime dt = locale.toDateTime("Jun 18 2015", "MMM dd yyyy");
Then if you also want locale dependent output use QLocale::toString.

Related

How to convert string “M/dd/yyyy hh:mm:ss tt” to "hh:mm tt" DateTime format from English to Spanish in Xamarin forms? [duplicate]

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

Issue with luxon date time parsing when zone is present in string

I am seeing error the input "06/09/22 02:14 CDT" can't be parsed as format MM/dd/yy HH:mm ZZZZ` when trying to get luxon date time from string.
DateTime.fromFormat("06/09/22 02:14 CDT","MM/dd/yy HH:mm ZZZZ")
Not sure what is the valid format I need to use when there is time zone in date string.
Thanks.
Issue is that you input contains CDT that is not recognized by Luxon since ZZZZ is not a valid token as explained in the Parsing -> Limitations section of the docs:
Not every token supported by DateTime#toFormat is supported in the parser. For example, there's no ZZZZ or ZZZZZ tokens. This is for a few reasons:
Luxon relies on natively-available functionality that only provides the mapping in one direction. We can ask what the named offset is and get "Eastern Standard Time" but not ask what "Eastern Standard Time" is most likely to mean.
Some things are ambiguous. There are several Eastern Standard Times in different countries and Luxon has no way to know which one you mean without additional information (such as that the zone is America/New_York) that would make EST superfluous anyway. Similarly, the single-letter month and weekday formats (EEEEE) that are useful in displaying calendars graphically can't be parsed because of their ambiguity.
You can add fixed string 'CDT' in your format or remove it completely from your input. You can use zone option (America/New_York in the example above, or America/Chicago in your use case) of DateTime#toFormat to take into account timezone offset.
Example:
const DateTime = luxon.DateTime;
const dt1 = DateTime.fromFormat("06/09/22 02:14 CDT","MM/dd/yy HH:mm 'CDT'", {zone: 'America/Chicago'})
const dt2 = DateTime.fromFormat("06/09/22 02:14", "MM/dd/yy HH:mm", {zone: 'America/Chicago'})
console.log(dt1.toISO());
console.log(dt2.toISO());
<script src="https://cdn.jsdelivr.net/npm/luxon#2.4.0/build/global/luxon.min.js"></script>

How to format Date from QString in QML

I am using QML Calendar and would like to set property of maximumDate and minimumDate.
According to the documentation
By default, this property is set to the latest maximum date (25 October, 275759 AD)
so I made an API that returns me this date in string format "25 October, 2018 AD"
when i try set
maximumDate = "25 October, 2018 AD"
QML throws me an error that i cannot assign QString to QDateTime
My question is how do format this string to date inorder for maximumDate to accept it. I was hoping to do it only in QML
There is no implicit conversion between a string and QDate, there is however one that works bidirectionally for QDate and qml's Date.
However, it doesn't seem like dates work with the format you are trying to use. I think you are confusing the stated date value as a literal value, when in fact it is just a human readable date.
So instead, you should try this:
maximumDate = Date.fromLocaleString(Qt.locale(), "2018-10-25", "yyyy-mm-dd")

How to convert a String into an Ecto.DateTime in Elixir?

I need to convert a string containing a valid UTC time to an Ecto.DateTime one, which I will insert it into my database with the correct format later. I have tried using the Ecto.DateTime.cast(date) method but it doesn't seem to work. The string is Sat Aug 04 11:48:27 +0000 2012 and comes from the Twitter API.
I know there are libraries such as Timex which I didn't inspect yet. Is there any easy working solution already built in Elixir?
There's no built-in solution in Elixir or Erlang for parsing DateTime values of this format:
Sat Aug 04 11:48:27 +0000 2012
You can certainly write a parser yourself, but it's neither going to be short or simple. You'll have to split the string, get the values of both date and time parameters, convert month strings to month integers, parse the timezone, represent the complete value in Elixir/Erlang DateTime formats and then finally cast it to Ecto.DateTime. See the following links:
Elixir Tips - Date Parsing
Erlang - How Can I Parse RFC1123 Dates Into An Erlang Term?
Convert timestamp to datetime in erlang
Using Timex is the best option here.
It's a well written library that allows you to stay away from the chaos of inner workings of Date/Time. With Timex, you can parse your string like this:
"Sat Aug 04 11:48:27 +0000 2012"
|> Timex.parse!("%a %b %d %T %z %Y", :strftime)
|> Ecto.DateTime.cast!
# => #Ecto.DateTime<2012-08-04 11:48:27>
Note: Timex has built-in support for a lot of the common DateTime formats, and I found it weird that a DateTime format being sent by Twitter wasn't supported - so I wrote one for you. Maybe double check to see if your string is correct? Also take a look at Timex Parsing and Formatting documentation.

Javascript ASP.net date format without timezone info - timezone offsets

I have a client side JavaScript that generates a date in JavaScript( new Date(2007,5,1)).
I need this date passed through to a hidden field that the code behind can access.
My issue is that when the hidden field is converted into a DotNet datetime, the time is incorrect. This is because the JavaScript is including timezone info from the client browser.
DotNet is then using this info to recalculate the time based on the difference between the server time and the client time.
What i need from the JavaScript is just the year, month and day.
I don't want to pass through 3 int values to my code behind as this will be a major change to the whole app.
What is the best way for me to accomplish this?
If i can set a UTC time with no timezone info I think that might work.
Any help is appreciated.
demo
If I understood it correctly,
you need .toDateString()
var date = new Date(2007,5,1);
document.write(date);
document.write("<br><br>versus<br><br>");
document.write(date.toDateString());
prints
Fri Jun 01 2007 00:00:00 GMT+0800 (Taipei Standard Time)
versus
Fri Jun 01 2007
You can use DateTimeOffset.ParseExact to parse a string to a DateTimeOffset value using the format you specify:
string dateString = "Fri Jun 01 2007 00:00:00 GMT+08:00";
DateTimeOffset date = DateTimeOffset.ParseExact(dateString, "ddd MMM dd yyyy hh:mm:ss 'GMT'zzz", CultureInfo.InvariantCulture);
You have to put GMT in quotes otherwise M will be interpreted as a format character.
Unfortunatelly, it is not possible to ignore part of the string value. If your string includes the name of the timezone you have to split it first and get the part without the description
string dateString = "Fri Jun 01 2007 00:00:00 GMT+08:00 (Taipei Standard Time)";
var parts=dateString.Split('(');
string datePart = parts[0].TrimEnd();
var date=DateTimeOffset.ParseExact(datePart,"ddd MMM dd yyyy hh:mm:ss 'GMT'zzz",CultureInfo.InvariantCulture);
You can build up a string from the javascript Date object you have created - it has getDate(), getMonth() and getFullYear() methods that you can use to build up the exact string you want in the hidden field.
I would recommend to use a format specification in C# when you get the values in the code behind file. Let me explain what I mean -
The date time format for the Date(...) in JavaScript is as follows
"Tue Jun 1 11:12:15 UTC+0530 2010"
which in C# would translate to the following format string -
"ddd MMM d hh:mm:ss UTCzzz yyyy"
with this format string use the DateTime.ParseExact(string <Hidden Field Value>, format, provider) to get the correct value for the datetime in C#.
Use provider as System.Globalization.CultureInfo.InvariantCulture.

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