How to remove specific JSON Key
How do I remove a property from a JavaScript object?
We've never had an explicit policy around downvoting -- users are free to, if they like, cast all their votes as downvotes. Whether this behavior is desirable or not is another matter.   Now, we do discourage downvoting by making downvotes cost -1 rep to the casting voter. But, there's nothing in our policy that says continual downvoting is bad or wrong or inappropriate.  However, my thoughts on this are changing. I no longer think it is community friendly behavior to cast an extreme number of downvotes, and I am considering an explicit policy forbidding it.  Some data points (as of today):  Total SO upvotes cast: 45,555,530  Total downvotes cast: 365,192  users with more than 100 downvotes cast: 596  users with > 100 downvotes and the lowest ratio of upvotes to downvotes:           |           |         | up:down user id | downvotes | upvotes |  ratio --------+-----------+---------+---------  187712 |       201 |      37 |    0.18    2525 |       580 |     149 |    0.25  136829 |       137 |      43 |    0.31   55943 |       438 |     140 |    0.31   19405 |       236 |      94 |    0.39    5640 |      3299 |    1337 |    0.40  180659 |       126 |      66 |    0.52   78613 |       348 |     198 |    0.56   39892 |       181 |     109 |    0.60     432 |       310 |     197 |    0.63  238704 |       198 |     132 |    0.66   12643 |       170 |     116 |    0.68   18256 |       219 |     152 |    0.69  122428 |       167 |     118 |    0.70  118854 |       120 |      86 |    0.71  105662 |       273 |     201 |    0.73  187690 |       135 |     101 |    0.74    1782 |       573 |     430 |    0.75   (this is a complete list, there are no more below this threshold.)  Based on this data I am leaning towards enforcing a "no more downvotes may be cast" if    You have at least (n) votes cast total Your upvote to downvote ratio is lower than ~ 0.5 When a player joins the server, this command block (containing gamemode 2 @a) puts them into gamemode 2/adventure mode. How can I change this so that only non-admin/not "opped" players' gamemode gets changed? An electron has no known internal structure, does that imply it has an unknown one? I'm currently reading Alonso and Finn's Electromagnetism book.  It explains that the spin contributes to the magnetic moment and is somewhat comparable to a rotation of the particle around its own axis. It says that the spin of a particle is caused by a certain internal structure, which makes sense in the aforementioned analogy.  Right underneath the paragraph with the explanation of spin, it says "The electron has no known internal structure", but since it does have a spin, does that mean that we know the electron has an internal structure but we just don't know what it is? I am trying to run some unit tests in a C# Windows Forms application (Visual Studio 2005), and I get the following error:  System.IO.FileLoadException: Could not load file or assembly 'Utility, Version=1.2.0.200, Culture=neutral, PublicKeyToken=764d581291d764f7' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)** at x.Foo.FooGO() at x.Foo.Foo2(String groupName_) in Foo.cs:line 123 at x.Foo.UnitTests.FooTests.TestFoo() in FooTests.cs:line 98** System.IO.FileLoadException: Could not load file or assembly 'Utility, Version=1.2.0.203, Culture=neutral, PublicKeyToken=764d581291d764f7' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)  I look in my references, and I only have a reference to Utility version 1.2.0.203 (the other one is old). Any suggestions on how I figure out what is trying to reference this old version of this DLL file? Besides, I don't think I even have this old assembly on my hard drive. Is there any tool to search for this old versioned assembly? I am a little bit confused by early stopping and in particular by how it can be inserted inside a CV framework. As far as I understand, I can fix the optimal number of epochs (for NN, or number of trees for XGB) by early stopping, that is:   pick a validation set, train with increasing number of epochs until a predefined metric evaluated on the validation set starts worsening that is the optimal number of epochs to prevent overfitting   and that's fine. But then I would like to insert this early stopping framework inside a CV framework: Suppose I have a model with 10 hyperparameters I want to fix via CV. And suppose that there is an eleventh hyperparameter, the number of epochs. My feeling is that one can do like this:   create the K resampled folds, for each of which you have a training and validation set choose a suitable grid for your 10 hyperparameters for each point on the grid train your model in each fold with early stopping, that is use the validation set of the fold to keep track of the preferred metric and stop when it gets worse take the mean of the K validation metric choose the point of the grid (i.e. the set of hyperparameters) that gives the best metric   Questions:   What number of epochs should I choose as optimal? in each of the K folds I have, in general, a different number of stopping epochs.  seems to suggest they take the mean of the K stopping epochs. Is this right? Is it actually a "fair" practice to use the validation metric coming from the early stopping as a proxy of the out-of-sample metric? As  in section 3.4.5, maybe the best thing to do would be:     ...if you want to do early stopping, then in each fold you should take your training set and split it again, holding out a small early-stopping-set to guide the early stopping, and then evaluate the model on the validation set of that fold.   But this seems to me a really intricate process...   Unfortunately, I wasn't able to find references where this issue is presented in a clear and transparent form. Close Lightning Modal by clicking anywhere outside of it Maximum area of isosceles triangle with perimeter 6 cm Problem. What is the side lengths of an isosceles triangle with $6cm$ perimeter which has the largest area? I solved this problem as below and I would like to learn  that if there is anything wrong: Let us say that the side lengths are $a$ and the bottom length is $6-2a$. By using pythagorean theorem we can conclude that the height $h$ is equal to $\sqrt{6a-9}$. Then, the area of the triangle can be given as $f(a)=(3-a)(\sqrt{6a-9})$. So $f'(a)=-\sqrt{6a-9}+\cfrac{3}{\sqrt{6a-9}}$. Finally, $f'(a)=\cfrac{12-6a}{\sqrt{6a-9}}$ and $f'(a)=0 \iff a =2$. WordPress Installation Failed I am trying to install Wordpress on Lubuntu. I followed the instructions . Including PHP Apache and MySQL setups. Apache and MySQL appear to be running fine.  However, when I go to http://localhost/blog/, I get the following error:     Neither /etc/wordpress/config-localhost.php nor /etc/wordpress/config-localhost.php could be found.   Ensure one of them exists, is readable by the webserver and contains the right password/username. Sorting an array of an array of objects in PHP by key value Basically I have a setup like the following:  Array (  [0] =&gt; Array ( [0] =&gt; stdClass Object ( [nid] =&gt; 1 [title] =&gt; title1 [uid] =&gt; 1 [parent] =&gt; 0 [weight] =&gt; -15 [name] =&gt; name1 [value] =&gt; 0 )                [1] =&gt; stdClass Object ( [nid] =&gt; 2 [title] =&gt; title2 [uid] =&gt; 1 [parent] =&gt; 0 [weight] =&gt; -7 [name] =&gt; name2 [value] =&gt; 100 )                [2] =&gt; stdClass Object ( [nid] =&gt; 3 [title] =&gt; title3 [uid] =&gt; 2 [parent] =&gt; 0 [weight] =&gt; -1 [name] =&gt; name3 [value] =&gt; 0 )                [3] =&gt; stdClass Object ( [nid] =&gt; 4 [title] =&gt; title4 [uid] =&gt; 2 [parent] =&gt; 0 [weight] =&gt; 1 [name] =&gt; name4 [value] =&gt; 80 )               )   )   What I need is a way to sort all the arrays inside the parent array by the [value] key in the Object. I've been trying for about 2 days now with usort and different methods but I just can't seem to get my head around it. The [value] key will range anywhere from 0 to 100 and I need all of the arrays sorted in decreasing order (IE: 100 down to 0). For which values of $\alpha$ and $\beta$ does the integral $\int\limits_2^{\infty}\frac{dx}{x^{\alpha}\ln^{\beta}x}$ converge? I'm trying to find out for which values of $\alpha$ and $\beta$ the integral $\int\limits_2^{\infty}\frac{dx}{x^{\alpha}\ln^{\beta}x}$ does converge. I know that when $\alpha=1$ then $\beta$ must be greater than $1$. I tried to use integration by  parts but It didn't work, so I would appreciate some hints. Thanks in advance. Invoking makeindex for nomencl I have spent many many hours failing to implement nomencl for my PhD thesis. The problem seems to be with invoking makeindex and creating the .nls file  I keep reading that I must invoke makeindex or write a Unix command:  makeindex filename.nlo  -s nomencl.ist -o filename.nls   But I don't know how to do this. I would be grateful for some instructions i.e. where do I type the command?    I am using TeXShop 2.43. This is a question of the book Linear Algebra of Kenneth Hoffman.  Describe explicitly all inner products on $\mathbb{R}$ and on $\mathbb{C}$.  I think that if $&lt;,&gt;$ is one inner product on $\mathbb{R}$ (or $\mathbb{C}$) then $&lt; ,&gt;=K[,]$, where $[,]$ is the standard inner product. Is that correct? Derivatives: enter "evaluated at" vertical bar with multiple values as subscripts Sorry for the long title, but how do I enter evaluated at (for a derivative), with multiple valuation criteria at the bottom of the the big | line?  Thanks! Why is there a temperature gradient on Earth? I was thinking about why the poles are colder and I came out with three possible explanations.  1. The atmosphere blocks light beams coming to poles    The Sun is seen only slightly over the horizon at the poles, so the light beams have longer way to the poles. If only this case were true, then the total difference between the poles and the equator would be the same as the energy that was absorbed by the atmosphere.  2. Sun is only slightly over the horizon at the poles.    Poles are often in shadow of the parts of the Earth which are closer to the equator.  3. Poles are farther from the Sun    The longer is the way to Sun the lower is the chance to catch a light from the Sun.  Please, correct me wherever I'm wrong. I'd like to know   Which of these three is most correct?  How significant are the described effects of the other explanations? Fantasy book, YA, Girl with magical powers & tattoos I read this book series in middle school. I believe that it would be classified as young adult fiction/fantasy. A girl has magical powers, and with her growing powers comes runes/tattoos in her arms. This is shown on every book cover. I know that one cover is blue. This one shows the girl in a black tank top and black pants. One is a yellow cover, with her in a dress (I think).  The girl has a friend/mentor, who she develops feelings for. The girl is the key to stopping a war between multiple factions/people. Each side is trying to use her to their advantage. I think the series was written in the early 2000s. Is it a good practice to place C++ definitions in header files? My personal style with C++ has always to put class declarations in an include file, and definitions in a .cpp file, very much like stipulated in . Admittedly, part of the reason I like this style probably has to do with all the years I spent coding Modula-2 and Ada, both of which have a similar scheme with specification files and body files. I have a coworker, much more knowledgeable in C++ than I, who is insisting that all C++ declarations should, where possible, include the definitions right there in the header file. He's not saying this is a valid alternate style, or even a slightly better style, but rather this is the new universally-accepted style that everyone is now using for C++. I'm not as limber as I used to be, so I'm not really anxious to scrabble up onto this bandwagon of his until I see a few more people up there with him. So how common is this idiom really? Just to give some structure to the answers: Is it now The Way™, very common, somewhat common, uncommon, or bug-out crazy? Find the determinant of $I + A$ Exact Sequences of Modules and Rank Suppose that:  $0 \rightarrow M_{1} \rightarrow M \rightarrow M_{2} \rightarrow 0$  Is an exact sequence of $R$-modules (for $R$ commutative integral domain). Show that $\mathrm{rk}(M) = \mathrm{rk}(M_{1})+\mathrm{rk}(M_{2})$    I have shown the inequality $\mathrm{rk}(M) \geq \mathrm{rk}(M_{1})+\mathrm{rk}(M_{2})$, however for the opposite direction I'm lost. I tried to take $N$ as a linear independent subset and tried to decompose it into $N_{1}$ (the elements in $\mathrm{Ker}(g)$) and $N_{2}$ (the elements not in $\mathrm{Ker}(g)$), but I haven't got far, since $N_{1}$ gives us a linearly independent set in $M_{1}$, however $N_{2}$ can give us a linearly dependent set in $M_{2}$.   We define $\mathrm{rk}(M)$ in this case as the supremum over all cardinalities of the linearly independent subsets of $M$ (where the only finite linear combination equaling $0$ implies trivial coefficients for $r \in R$).  Would this be the proper way to show the result? I think I'm missing something important. What is the logical form of the definition of validity? My text book gives the definition of validity as "An argument is valid IFF if the premises are true, then the conclusion must be true". Using a conditional elimination on the RHS of the IFF yields "An argument is valid IFF the premises are false or the conclusion is true".   Yet, this seems strange to me. Am I doing something incorrect with my manipulation or is this definition actually true? Surely the criteria for a valid argument goes beyond a false set of premises or a true conclusion. I recently installed Lubuntu but I have a problem with Adobe Flash Player. I always see something that looks like this when I open a video:    (source: )    The video is small, grainy, and is green and purple.  I tried to reinstall Flash and to test it in multiple browsers without success. I installed an older version of Flash but no result.  [0300]: Intel Corporation 82865G Integrated Graphics Controller [8086:2572] (rev 02)     Subsystem: Hewlett-Packard Company D530 sff(dc578av) [103c:12bc]     Kernel driver in use: i915