Array in javascript not returning values
How to return value from an asynchronous callback function?
In a complete metric space with no isolated points, any countable intersection of open dense sets is uncountable? I was looking for some package (nautilus-terminal), and accidentally did this:  $ sudo apt-get install nautilus- Reading package lists... Done                                                                                                                                                                                                  Building dependency tree                                                                                                                                                                                                       Reading state information... Done                                                                                                                                                                                              The following packages were automatically installed and are no longer required:                                                                                                                                                  apturl apturl-common libgail-3-0 linux-headers-4.4.0-57 linux-headers-4.4.0-57-generic linux-image-4.4.0-57-generic linux-image-extra-4.4.0-57-generic                                                                       Use 'sudo apt autoremove' to remove them.                                                                                                                                                                                      The following packages will be REMOVED:                                                                                                                                                                                          gnome-session-flashback nautilus nautilus-sendto nautilus-share ubuntu-desktop                                                                                                                                               0 upgraded, 0 newly installed, 5 to remove and 69 not upgraded.                                                                                                                                                                After this operation, 2 031 kB disk space will be freed.                                                                                                                                                                       Do you want to continue? [Y/n] ^[[^C                                                                                                                                                                                             That's quite dangerous because remove is much harder to mistype than a simple dash from a failed autocompletion.     Is that an equivalent of apt-get remove? I couldn't find any documentation for that. Edit: except for overlooking the man page... Selecting one every n frames from a video using ffmpeg Causes of hexagonal shape of Saturn's jet stream NASA has just shown a more detailed picture of the hexagonal vortex/storm on Saturn:           Is that theoretically understood what is the cause behind this eye-catching nontrivial, regular yet not circular, shape? If so, what is the cause? I expect some explanation in terms of "nonlinear equations" of "mathematical physics" and "solitons".  P.S. (added a day after this question and the first answer was posted): On  where I posted the same question, people came up with some articles and phrases like "Rossby waves" and "resonance of latitude-dependence Coriolis frequency". Make display of reputation in revisions list consistent with the user card display If two gravitational waves came in contact with each other what would happen? In another question entirely, what happens when a higher gravitational field interacts with a weaker one. Restore main APFS container to full disk When adding NOT NULL columns with a DEFAULT value - does PostgreSQL optimize this operation?  In case the table has n rows, a not-optimized alter-table-add-column would yield n writes of the default value - which could be very painful, obviously. With the optimization the DB would instantaneously create the new column, store just one copy of the default value which would be returned when no non-default value is found for that column in a suitable index data structure.  For example  such an . What is the difference between conditioning on regressors vs. treating them as fixed? How can I add a new user as sudoer using the command line? Do posts have to be in English on Stack Exchange? Otherwise known as  必须用英语吗？(is English required?) ¿Necesito hablar en inglés? ?האם אני חייב לכתוב באנגלית Muss ich auf Englisch schreiben?  Do I have to use English when posting a question, an answer or a comment on a Stack Exchange site? How to escape quotes in shell? I'm having trouble with escaping characters in bash. I'd like to escape single and double quotes while running a command under a different user. For the purposes of this question let's say I want to echo the following on the screen:  'single quote phrase' "double quote phrase"   How can I escape all the special chars, if I also need to switch to a different user:  sudo su USER -c "echo \"'single quote phrase' \"double quote phrase\"\""   Of course, this doesn't produce the right result. How to create a generic array in Java? Due to the implementation of Java generics, you can't have code like this:   public class GenSet&lt;E&gt; {     private E a[];      public GenSet() {         a = new E[INITIAL_ARRAY_LENGTH]; // error: generic array creation     } }   How can I implement this while maintaining type safety?  I saw a solution on the Java forums that goes like this:  import java.lang.reflect.Array;  class Stack&lt;T&gt; {     public Stack(Class&lt;T&gt; clazz, int capacity) {         array = (T[])Array.newInstance(clazz, capacity);     }      private final T[] array; }   But I really don't get what's going on. Practical Uses for the "Curiously Recurring Template Pattern" What are some practical uses for the ""?  The "" example commonly shown just isn't a convincing example to me. Let $K=F(x)$ be the rational function field over a field $F$ of characteristic $0$, let $L_1=F(x^2)$, and $L_2=F(x^2+x)$. How to show that $L_1\cap L_2 = F$? Could it be that Goldbach conjecture is undecidable? I am trying to show $$\lim_{n\rightarrow \infty} \int_{[0,1]^n} \frac{|x|}{\sqrt{n}}dx=\frac{1}{\sqrt{3}}$$ where $[0,1]^n$ is the unit cube in $\mathbb{R}^n$. I would appreciate any hint. Short circuit or disconnect to bypass a compressor I have an Altec Lansing ATP3 2.1 audio system PCB which I reverse-engineered, and I would like to bypass the JFET compressor that's on it. Its active components are a JFET and four op-amps. I will connect the input to the output so it gets forwarded to the next stage.  My question is: should I disconnect the input and output from the compressor (in that case should I remove power supply as well, which would be very annoying), or can I leave it connected but short-circuited?  The block I want to short-circuit is the pink one on the left.    I realize the image is very small. The sound comes in on the right, in the green box. In the middle yellow box there's some trebble/volume/bass control. The small green box on its left merges the left and right channels to forward it to the subwoofer section, which is the complete left half of this diagram (except the red box on the left, which is just power). Signal then goes through a low-pass, a small equalizer and a compressor (the big purple box). It finally gets amplified in the brown power amp. A problem of Schwarz-Pick theorem in complex analysis Set $f \in H(B(0,1)),f(B(0,1)) \subset B(0,1)$，prove that $$|f(z)-\frac{f(0)(1-|z|^2)}{1-|f(0)|^2||z|^2}| \le \frac{|z|(1-|f(0)|^2)}{1-|z|^2|f(0)|^2}$$  I think this problem is supposed to be proved by Schwarz-Pick theorem, I tried hard but failed to build a function to prove it. I even doubted that this problem is wrong, so I want to whether this problem can be proved or be falsified, and how.  Any help would be appreciated. Many times I have read statements like, "the age of the universe is 14 billion years" . For example this wikipedia page .   Now, my question is, which observers' are these time intervals? According to whom 14 billion years?