Develop Reference

Getting the latest pair value with Kraken API

I am trying to get the latest value/rate for a given pair using the Kraken API, but I cannot really figure it out.
Is there anyone that knows how to do it?
I am using the C# code provided on Git (https://github.com/trenki2/KrakenApi) and thought using the following function was the way to go:
client.GetRecentTrades("XETHZEUR",ID)
I however don't want to use an ID, which seems to be optional according to Kraken Website.
I just want to know what is the current value, nothing more.
I have also used GetTicker to get the last trade, but this does not come with a Time stamp and will not give the actual currency pair value.
Cheers

Both GetTicker and GetRecentTrades will give you the value of the last trade. You can use either depending on what other data you need. I guess there could be some difference because most likely Kraken caches the results.
Of the two methods above only GetRecentTrades will provide a timestamp.
Alternatively instead of getting the last trade you can call GetOrderBook and calculate the average between the lowest Ask price and highest Bid price.

formatting dates incorrectly, trying to understand the reason

sorry if this question is a little ... strange, but I am a little lost to what is happening and how to control it. What I need to better understand is the following:
I have an ASP MVC application that works with Linq-To-SQL and an MSSQL server. The application is an inside (office only) website, and I am mentioning that so it wont sound that strange when I say that we wanted to ignore browser language, culture, date, whatever... settings and always display the date in the format "dd/MM/yyyy". Always.
So, now that I am testing a specific form in the website I encounter something very, very strange.
The first strange thing is that the date is not displayed on the screen correctly. Let me elaborate, I have a simple view that gets some data, read from the database, inside a model. So, as I fought for sometime with teaching the datetime object to display in a certain way on server level (meaning giving it an attribute like [Display(..)] or [DataType(...)] didn't force the date to look the way I want, so I simply wrote the following:
<input id="BirthDate" name="BirthDate" type="text" value="<%= Model.BirthDate.HasValue ? Model.BirthDate.Value.ToString("dd/MM/yyyy") : "" %>" class="text-box datepicker" />
However, even though I am specifically formatting the date to display "dd/MM/yyyy" in the input, it doesnt. When the browser settings are Dutch, the value inside this box is displayed with 'dd-MM-yyyy'.
I can somehow accept that, the browser is a smart guy(or gal) and identifies that the value in the box is a date and applies formatting according to the selected language settings. I don't know how to tell it not to screw with my dates, but I can get to believe that this is what happens. HOWEVER, what I am finding a lot difficult to accept is that THE Date formatting somehow goes back to the database. This sentance didnt really mean anything so I am explaining again. I have a table that has a few columns, one of them being a varchar(100). Super, and because of some very interesting designing, that field can contain text, dates and whatever.
So, because the field is a string, and later on I simply display it in a paragraph and dont need to do the whole dance of casting it to a DateTime object and then formatting it back when it gets in the view (which works so perfectly as I previously mentioned) I simply save it in the table in the correct format (dd/MM/yyyy).
Yea, but not really. My code would look like that:
var date = DateTime.Now;
db.EmployeeHistory log = new EmployeeHistory();
log.ActionType = 1;
log.EmployeeId = 1671;
log.At = date;
log.Context = "A TEST";
log.ObjectTitle = "Who cares";
log.EmployeeHistoryChangesSets.Add(new EmployeeHistoryChangesSet()
{ PropertyName = "TEST PROPERTY", NewValue = date.ToString("dd/MM/yyyy"), OldValue = date.ToString() });
dataContext.EmployeeHistories.InsertOnSubmit(log);
dataContext.SubmitChanges();
This is a of course a test, one that didnt make me happy at all. Because, if you are paying attention, there is a field in the database which is mapped to a string (varchar(...)) and then I am taking the Date, make it a string with the .ToString() method while formatting it into a "dd/MM/yyyy" format. So I am not using dates (well I am using a Date object to get the date, but I am converting it to a string) I am using only strings.
And somehow, for some reason that is truly escaping me, the string/date is saved in the database in the format: 'dd-MM-yyyy'. I really didnt expect it to behave in such a way. At first I was going to accept my fate, even though I was having a really hard time accepting that the database will take the liberty to format my input even though IT IS a string.
So, further testing showed me that the Date.ToString("dd/MM/yyyy") method actually returns the date in 'dd-MM-yyyy', depending on the browser language settings. Meaning that if I change my settings and it works correctly again ("dd/MM/yyyy").
So, my question is, what am I missing? Why is the .ToString() method not formatting the date correctly? Is my analisys correct or am I up and to the right on this one? If there is a good reason for that (even though I cant come up with one), should I just create my own extension method for DateTime class and implement the formatting mannualy or is there a better way?
I am really sorry for the long post (again). I would appreciate some clarity, as the whole project will behave this way. Thanks in advance

How can I create or set JodaTime DateTime objects with/to maximum value?

I am translating some C#-code to Java, and have chosen JodaTime's DateTime class, to replace C#'s System.DateTime.
In C# the DateTime class has a Field called MaxValue and one called MinValue, which returns the biggest and smallest possible value that the DateTime object can hold.
I am trying to achieve the same with the JodaTime api. I have read some suggestions on other posts
This one: Java equivalent of .NET DateTime.MinValue, DateTime.Today answers how to make today's date in JodaTime, but when answering the second half of the question, about Min Values, they turn to Calendar and Date
Likewise I have seen suggestions about passing a maximized long value as constructor parameter, but it was criticized for being dependant on classes that might be changed in the future, and therefor might not be compatible or accurat after API updates.
So, is there a single positively correct way to do this? If not, is there a good way to achieve this?

Java 8 LocalDate has two values. LocalDate.MAX and LocalDate.MIN
LocalDate.MAX - The maximum supported LocalDate, '+999999999-12-31'. This could be used by an application as a "far future" date.
LocalDate.MIN - The minimum supported LocalDate, '-999999999-01-01'. This could be used by an application as a "far past" date.
Note: these do not translate to Long.MIN_VALUE or Long.MAX_VALUE.
I suggest using Java 8 if migrating from C# and how date/time works is important to you, as it has closures AND a new DateTime API based on JodaTime. This new DateTime API is the one you should be using if you are worried about the future of an API.
I think you can assume that Long.MIN_VALUE and Long.MAX_VALUE will never change as they are based on the definition of how a signed 64-bit values work. (How 64-bit values work was standardised before you were born, most likely) You can also assume that Date will not change as it hasn't change much since it was released and since it has been replaced there is even less reason to change it. In theory it might be deprecated, but in reality there is still too much code which uses it.
IMHO, I use long to represent a time in milli-seconds ala System.currentTimeMillis() and I use Long.MIN_VALUE and Long.MAX_VALUE.
If you are concerned about using good API and future proofing your code, I suggest you avoid using Calendar. Not that it is all bad, but there are good reasons to want to replace it.

Methodologies or algorithms for filling in missing data

I am dealing with datasets with missing data and need to be able to fill forward, backward, and gaps. So, for example, if I have data from Jan 1, 2000 to Dec 31, 2010, and some days are missing, when a user requests a timespan that begins before, ends after, or encompasses the missing data points, I need to "fill in" these missing values.
Is there a proper term to refer to this concept of filling in data? Imputation is one term, don't know if it is "the" term for it though.
I presume there are multiple algorithms & methodologies for filling in missing data (use last measured, using median/average/moving average, etc between 2 known numbers, etc.
Anyone know the proper term for this problem, any online resources on this topic, or ideally links to open source implementations of some algorithms (C# preferably, but any language would be useful)

The term you're looking for is interpolation. (obligatory wiki link)
You're asking for a C# solution with datasets but you should also consider doing this at the database level like this.
An simple, brute-force approach in C# could be to build an array of consecutive dates with your beginning and ending values as the min/max values. Then use that array to merge "interpolated" date values into your data set by inserting rows where there is no matching date for your date array in the dataset.
Here is an SO post that gets close to what you need: interpolating missing dates with C#. There is no accepted solution but reading the question and attempts at answers may give you an idea of what you need to do next. E.g. Use the DateTime data in terms of Ticks (long value type) and then use an interpolation scheme on that data. The convert the interpolated long values to DateTime values.

The algorithm you use will depend a lot on the data itself, the size of the gaps compared to the available data, and its predictability based on existing data. It could also incorporate other information you might know about what's missing, as is common in statistics, when your actual data may not reflect the same distribution as the universe across certain categories.
Linear and cubic interpolation are typical algortihms that are not difficult to implement, try googling those.
Here's a good primer with some code:
http://paulbourke.net/miscellaneous/interpolation/
The context of the discussion in that link is graphics but the concepts are universally applicable.

For the purpose of feeding statistical tests, a good search term is imputation - e.g. http://en.wikipedia.org/wiki/Imputation_%28statistics%29

c#: tryparse vs convert

Today I read an article where it's written that we should always use TryParse(string, out MMM) for conversion rather than Convert.ToMMM().
I agree with article but after that I got stuck in one scenario.
When there will always be some valid value for the string and hence we can also use Convert.ToMMM() because we don't get any exception from Convert.ToMMM().
What I would like to know here is: Is there any performance impact when we use TryParse because when I know that the out parameter is always going to be valid then we can use Convert.ToMMM() rather TryParse(string, out MMM).
What do you think?

If you know the value can be converted, just use Parse(). If you 'know' that it can be converted, and it can't, then an exception being thrown is a good thing.
EDIT: Note, this is in comparison to using TryParse or Convert without error checking. If you use either of the other methods with proper error checking then the point is moot. I'm just worried about your assumption that you know the value can be converted. If you want to skip the error checking, use Parse and die immediately on failure rather than possibly continuing and corrupting data.

When the input to TryParse/Convert.ToXXX comes from user input, I'd always use TryParse. In case of database values, I'd check why you get strings from the database (maybe bad design?). If string values can be entered in the database columns, I'd also use TryParse as you can never be sure that nobody modifies data manually.
EDIT
Reading Matthew's reply: If you are unsure and would wrap the conversion in a try-catch-block anyway, you might consider using TryParse as it is said to be way faster than doing a try-catch in that case.

There is significant difference regarding the developing approach you use.
Convert: Converting one "primitive" data in to another type and corresponding format using multiple options
Case and point - converting an integer number in to its bit by bit representation. Or hexadecimal number (as string) in to integer, etc...
Error Messages : Conversion Specific Error Message - for problems in multiple cases and at multiple stages of the conversion process.
TryParse: Error-less transfer from one data format to another. Enabling T/F control of possible or not.
Error Messages: NONE
NB: Even after passing the data in to a variable - the data passed is the default of the type we try to parse in to.
Parse: in essence taking some data in one format and transfer it in to another. No representations and nothing fancy.
Error Messages: Format-oriented
P.S. Correct me if I missed something or did not explain it well enough.