How can I use linq distinct operator here to remove remove duplicate courses.Cours.Name,  var coursesList = from courses in not_subsribe   select new SelectListItem   {       Text = courses.Cours.Name,       Value = courses.Cours.ID       .ToString()   };
I am playing with LINQ to learn about it, but I can't figure out how to use Distinct when I do not have a simple list (a simple list of integers is pretty easy to do, this is not the question). What I if want to use  on a list of an Object on one or more properties of the object?  Example: If an object is Person, with Property Id. How can I get all Person and use Distinct on them with the property Id of the object?  Person1: Id=1, Name="Test1" Person2: Id=1, Name="Test1" Person3: Id=2, Name="Test2"   How can I get just Person1 and Person3? Is that possible?  If it's not possible with LINQ, what would be the best way to have a list of Person depending on some of its properties in .NET 3.5?
Why can't ARIMA model large lags and/or long range dependence? ARIMA cannot model large lags (obtained from autocorrelation plot) and long range dependency (hurst exponent $H &gt; 0.5$). Why is it so? The suggested edits count at top is incorrect. Multiple browser refreshes did not clear it. Approving/Rejecting review decreases the count, but as you can see the count is incorrect. What is the most efficient way to clone a JavaScript object? I've seen obj = eval(uneval(o)); being used, but . I've done things like obj = JSON.parse(JSON.stringify(o)); but question the efficiency.  I've also seen recursive copying functions with various flaws.  I'm surprised no canonical solution exists. How well-known is the theology of Middle-earth, in Middle-earth? One thing that is notably absent in Middle-earth is any mention of temples, churches, priests or religious rites.  There are passing mentions of Men who would "worship" Sauron, but generally the world of Middle-earth seems much less religious than medieval Europe, or even classical antiquity.  One never hears about "the cult of Aule" or "the cult of Yavanna," although historically there were many "cults of Athena" or "cults of Poseidon."  Aragorn doesn't (to my memory) make an offering to Tulkas before battle, nor does he pray to Eru Ilúvatar for victory, and all the holidays and solemnities seem to commemorate historical figures, not religious ones.  This is especially strange in a world where there are still living witnesses, like Galadriel, to the actions of the Valar and other "divine" beings, and where there are still Maiar wandering around talking to people and putting on flashy firework shows.  Now, a lot of people talk about how Tolkien didn't want the Valar to be considered "gods," but at the same time he did use phrases like "the gods of old" numerous times.  Clearly, these beings would have qualified for worship in most cultures.  And even without the Valar being considered a true pantheon, there is still Eru, a closer analogue to the Christian God of Tolkien's beliefs, and we know the denizens of Middle-earth knew of him (Him?) because of the line "Eru, who in Arda is called Ilúvatar."  And yet, Ilúvatar seems not to be terribly important to anyone on a daily basis.  So my question is this: how familiar with the "theology" of Middle-earth were the citizens of Middle-earth?  Would the average merchant in Rohan know about the Valar and the Maiar and Iluvatar and the Music of the Ainur?  The average noble in Minas Tirith?  The younger Elves, like Legolas?  The Dwarf Lords?  Were the theological truths about the formation of the world, the Valar and the Maiar just so well known that they weren't worth commenting on, or had they been forgotten by most?  And if they had been forgotten, why wasn't the knowledge (whether through deliberate teachings or casual conversation) re-invigorated by witnesses like Gandalf or Galadriel? (1)  If $E$ is a subset of $\mathbb R$ with finite outer measure, i.e. $m^{*}(E) &lt;\infty$; and   (2) $E$ is not Lebesgue measurable, i.e. there exists $F$ such that  $m^{*} (F) &lt; m^{*}(EF) + m^{*}(FE^{c}).$  [Claim] There exists an open set $O\supset E$ with finite outer measure, such  that   $$m^{*}(O E^{c})  &gt; m^{*} (O)  - m^{*} (E).$$  My  questions are the following.  (1) Is the above claim correct? I've seen this in Royden's book, but have a bit concern. Note that a set $E$ is Leb measurable if  it satisfies caratheodory condition: $m^{*} (F) = m^{*}(EF) + m^{*}(FE^{c})$ for  all subset $F$. If the claim is yes, it seems that measurability condition can  be reduced from all subset $F$ to Borel set $F$.  (2) If the claim is correct, a proof is needed. Where can we find frequently updated details about travel/entry restrictions due to Coronavirus (nCoV-19)? Explicit "do not award bounty" button Shouldn't there be a way to prevent automatic awarding of a bounty? For example, if someone provides an answer that sounds good but is totally wrong, it may happen that it gets a score of +2, but doesn't deserve the bounty. If no one else answers, half the bounty will automatically go to this person. Automatic awarding is good if an inactive user offers a bounty, but I think there should be a button that basically means "I know the bounty should now be awarded, but I have read the answers and none of them deserve the bounty".  The button should obviously not refund the bounty, just let it go to /dev/null instead of awarding it to someone who doesn't deserve it. How to perform a logistic regression for more than 2 response classes in R I want to predict the impact of oil price over a Colombian oil company's stock price. I plan to use a logistic regression for this with a categorical variable (Up or Down given the direction of the stock price). Here is part of my dataset:  Minute  ecopet  profit  sum_profit   direccion  cl1_chg   sum_cl1    direccion_cl1 571     2160     0       10           Up         -0.03     0.00      Down 572     2160     0        0           Neutral     0.07    -0.03      Down 573     2160     0       -5           Down       -0.08     0.04      Up 574     2160     0       -5           Down       -0.07    -0.04      Down 575     2160     5       -5           Down       -0.08    -0.11      Down 576     2165     0       -25          Down        0.00    -0.19      Down 577     2165     0       -25          Down       -0.05    -0.19      Down 578     2165     0       -15          Down       -0.17    -0.24      Down 579     2165     5       -15          Down       -0.06    -0.41      Down 580     2170     0       -20          Down        0.03    -0.47      Down 581     2170    -10       0           Neutral     0.04    -0.44      Down   My dependent variable is 'direccion'. But as you can see it has 3 response classes. I know that to implement a binary logistic regression in R the code is:  glm.fit=glm(direccion~direccion_cl1, data=datos, family=binomial)   I am working with intraday information and plan to predict what happens when the oil moves up/ down (in the previous 10 minutes) and how it impacts the stock price in the next 10 minutes.  Could anyone tell me how could I perform this? I don't really know how to perform the logistic regression with 3 response classes. Thanks! $|p(z)| \leq M$ for $|z| \leq 1$ Show that $|p(z)| \leq M|z|^n$ for $|z| \geq 1$ Let $p(z)= \sum_{k=0}^n a_k z^k$ ,  $a_n \neq 0$ , be a polynomial of degree $n$ such that $|p(z)| \leq M$ for $|z| \leq 1$.  Show that $|p(z)| \leq M|z|^n$ for $|z| \geq 1$  This was an exam question. Part (a) of this question asked the converse: if $|p(z)| \leq M|z|^n$ and $|z|$ is sufficiently large, then $p(z)$ is a polynomial. This question came straight out of Ahlfors' Complex Analysis, which I solved by showing, using the Cauchy Estimate,  $|p^n (z)|  \leq \frac{n!M|z|^k}{R^n} = 0$ as $R \to \infty$.   I would like to work backwards with this.   May I do this, or similar:   $p(z) = \frac{1}{2\pi i} \int_{c} \frac{f(\zeta)d\zeta}{\zeta-z}$  $\Rightarrow  |p(z)| \leq \frac{2\pi M|z|^n}{1(2\pi)}= M|z|^n$ I am trying to define an rgb color. More specifically I want to create this color    which in rgb mode it's (98,190,177).  I tried to define this color using the following code  \documentclass{standalone}  \usepackage{tikz}  \begin{document}  \definecolor{tank}{rgb}{0.098,0.190,0.177}  %\definecolor{tank}{rgb}{98,190,177}  \begin{tikzpicture}   \coordinate (tank) at (0,0);   \draw[red, fill=tank] (-2,0.5)--(-0.5,1)--(0.5,1)--(2,0.5)--(2,-0.5)--(0.5,-1)--(-0.5,-1)--(-2,-0.5)--cycle;  \end{tikzpicture} \end{document}   but the output is totally different from what I am trying to achieve    I also tried to use \definecolor{tank}{rgb}{98,190,177} but I get no color at all. How to properly define an rgb color? Regexp that matches valid regexps Here is the script to create my tables:   CREATE TABLE clients (    client_i INT(11),    PRIMARY KEY (client_id) ); CREATE TABLE projects (    project_id INT(11) UNSIGNED,    client_id INT(11) UNSIGNED,    PRIMARY KEY (project_id) ); CREATE TABLE posts (    post_id INT(11) UNSIGNED,    project_id INT(11) UNSIGNED,    PRIMARY KEY (post_id) );   In my PHP code, when deleting a client, I want to delete all projects posts:  DELETE  FROM posts INNER JOIN projects ON projects.project_id = posts.project_id WHERE projects.client_id = :client_id;   The posts table does not have a foreign key client_id, only project_id. I want to delete the posts in projects that have the passed client_id.  This is not working right now because no posts are deleted. How do I do a case-insensitive string comparison? Consider the following:   $1 = 1^2$ $2 + 2 = 2^2$ $3 + 3 + 3 = 3^2$   Therefore,   $\underbrace{x + x + x + \ldots + x}_{x \textrm{ times}}= x^2$   Take the derivative of lhs and rhs and we get:   $\underbrace{1 + 1 + 1 + \ldots + 1}_{x \textrm{ times}} = 2x$   Which simplifies to:   $x = 2x$   and hence    $1 = 2$.     Clearly something is wrong but I am unable pinpoint my mistake. How to implement an abstract class in ruby? I know there is no concept of abstract class in ruby. But if at all it needs to be implemented, how to go about it? I tried something like...  class A   def self.new     raise 'Doh! You are trying to write Java in Ruby!'   end end  class B &lt; A   ...   ... end   But when I try to instantiate B, it is internally going to call A.new which is going to raise the exception.  Also, modules cannot be instantiated but they cannot be inherited too. making the new method private will also not work. Any pointers? Finding multivariable limits for the function $\frac{3x^2y}{x^2+y^2}$ Command to open a URL Is there a command I can use in Bash that will open a specific URL in the default browser? Absolute path & Relative Path What's the difference between absolute path &amp; relative path when using any web server or Tomcat? Clearing NSUserDefaults I'm using +[NSUserDefaults standardUserDefaults] to store application settings. This consists of roughly a dozen string values. Is it possible to delete these values permanently instead of just setting them to a default value? I just updated my iMac to Mojave, and am still trying to setup my preferences.  I tried dark mode, but did not like it (half of me apps seem to ignore it anyway).  I switched to light mode, but this too has problems. The File Save dialog shows a list of Directories and existing files, but the latter are very light grey, almost indistinguishable from the background.    I have searched the Preferences menu, but can't seem to find any setting to set normal contrast levels like in High Sierra.