When try something like this in JavaScript ['10','10','10'].map(parseInt)   You will get this is as a result: [ 10, NaN, 2 ]  Why does this happen?
From the :  [1,4,9].map(Math.sqrt)   will yield:  [1,2,3]   Why then does this:  ['1','2','3'].map(parseInt)   yield this:  [1, NaN, NaN]   I have tested in Firefox 3.0.1 and Chrome 0.3 and just as a disclaimer, I know this is not cross-browser functionality (no IE).  I found out that the following will accomplish the desired effect. However, it still doesn’t explain the errant behavior of parseInt.  ['1','2','3'].map(function(i){return +i;}) // returns [1,2,3]
How to remove link for an application in new Google Launcher? Getting computer's UTC offset in Python Circuitikz symbols in TikZ circuit library Some time ago, I asked about . wh1t3 wrote: "However, as far as I know there is nothing the circuitikz package does that the TikZ circuit library can't."  So if it is true that the tikz library is more powerful, how do I get all the symbols described in the  using the TikZ circuit library?  Especially I am missing the symbols for ammeters and voltmeters. Java Strings: "String s = new String("silly");" List or IList Can anyone explain to me why I would want to use IList over List in C#?  Related question: JavaScript 64 bit numeric precision Is there a way to represent a number with higher than 53-bit precision in JavaScript? In other words, is there a way to represent 64-bit precision number?  I am trying to implement some logic in which each bit of a 64-bit number represents something. I lose the lower significant bits when I try to set bits higher than 2^53.  Math.pow(2,53) + Math.pow(2,0) == Math.pow(2,53)   Is there a way to implement a custom library or something to achieve this? 80's Animated movie: An old man joins mission to save a boy stranded on a hostile world A guy on a space ship picks up a distress call, a boy is stranded on a planet with a hostile environment. He &amp; his crew go to the rescue, stopping on the way to pick up an old man who comes with them. Most of the top of the old guy's skull is metal, from an old injury.  They've various adventures on the way (their ship is boarded by pirates/bandits/hostile forces at one point).  They get to the planet with the boy. They've limited time to save him as the planet is being moved back in time. (I can't remember why) When they find the boy, he's being attacked by giant wasp-type-things.   The boy is injured on the top of his head. The old guy dies protecting him. The boy gets shifted back in time with the planet and - you guessed it - survives, grows up and turns out to be the old guy.  Now that I've remembered some of it, the bits I can't remember are driving me crazy. I'd love to see this again, if I could identify it I might be able to track down a copy.  I'd swear I saw this mid 80's on morning TV, but it I could be out by 5 years either way. Thanks How to find unused/dead code in java projects What tools do you use to find unused/dead code in large java projects? Our product has been in development for some years, and it is getting very hard to manually detect code that is no longer in use. We do however try to delete as much unused code as possible.  Suggestions for general strategies/techniques (other than specific tools) are also appreciated.  Edit: Note that we already use code coverage tools (Clover, IntelliJ), but these are of little help. Dead code still has unit tests, and shows up as covered. I guess an ideal tool would identify clusters of code which have very little other code depending on it, allowing for docues manual inspection. Why is the determinant of a symplectic matrix 1? Suppose $A \in M_{2n}(\mathbb{R})$. and$$J=\begin{pmatrix} 0 &amp; E_n\\   -E_n&amp;0  \end{pmatrix}$$ where $E_n$ represents identity matrix. if $A$ satisfies $$AJA^T=J.$$ How to figure out $$\det(A)=1~?$$ My approach: I have tried to separate $A$ into four submartix:$$A=\begin{pmatrix}A_1&amp;A_2 \\A_3&amp;A_4 \end{pmatrix}$$ and I must add a assumption that $A_1$ is invertible. by elementary transfromation:$$\begin{pmatrix}A_1&amp;A_2 \\ A_3&amp;A_4\end{pmatrix}\rightarrow \begin{pmatrix}A_1&amp;A_2 \\ 0&amp;A_4-A_3A_1^{-1}A_2\end{pmatrix}$$ we have: $$\det(A)=\det(A_1)\det(A_4-A_3A_1^{-1}A_2).$$ From$$\begin{pmatrix}A_1&amp;A_2 \\ A_3&amp;A_4\end{pmatrix}\begin{pmatrix}0&amp;E_n \\ -E_n&amp;0\end{pmatrix}\begin{pmatrix}A_1&amp;A_2 \\ A_3&amp;A_4\end{pmatrix}^T=\begin{pmatrix}0&amp;E_n \\ -E_n&amp;0\end{pmatrix}.$$ we get two equalities:$$A_1A_2^T=A_2A_1^T$$ and $$A_1A_4^T-A_2A_3^T=E_n.$$ then $$\det(A)=\det(A_1(A_4-A_3A_1^{-1}A_2)^T)=\det(A_1A_4^T-A_1A_2^T(A_1^T)^{-1}A_3^T)=\det(A_1A_4^T-A_2A_1^T(A_1^T)^{-1}A_3^T)=\det(E_n)=1,$$ but I have no idea to deal with this problem when $A_1$ is not invertible. LaTeXiT is cropping the pdf I am using LaTeXiT (pierre chachatelier, www.chachatelier.fr) - latex equation editor for Powerpoint for mac.  It's producing pdf that appear to be "cropped" on top (see attached) - I've tried already with changing the "margins" option (Preferences>General) but unsuccessfully - don't think that's the problem.   Any hint?   Thanks I've always been one to simply use:  List&lt;String&gt; names = new ArrayList&lt;&gt;();   I use the interface as the type name for portability, so that when I ask questions such as these I can rework my code.    When should  be used over  and vice-versa? I am trying to pull logs and doing few others things directly. written a small line BASH but not working. I am sure thats with IF Condition.    sed -rne '/21:25:07/,/21:50:07/ p'  server.log.2015-04-21 &gt; /tmp/filename.log ; du -sh  /tmp/filename.log ;  if [`du -sh  /tmp/filename.log` -gt 0] then gzip /tmp/filename.log ; How do we know that certain quantum effects are random? $X/{\sim}$ is Hausdorff if and only if $\sim$ is closed in $X \times X$ $X$ is a Hausdorff space and $\sim$ is an equivalence relation.  If the quotient map is open, then $X/{\sim}$ is a Hausdorff space if and only if $\sim$ is a closed subset of the product space $X \times X$.  Necessity is obvious, but I don't know how to prove the other side. That is, $\sim$ is a closed subset of the product space $X \times X$ $\Rightarrow$ $X/{\sim}$ is a Hausdorff space. Any advices and comments will be appreciated. How do I change the login manager's keyboard layout? I have a netbook with an AZERTY layout. I've changed it to "bépo" to try it, but now I've reset it to a french layout.  While all the apps have taken the change into account, Ubuntu's login manager still uses bépo, making entering passwords a challenge. I've enabled the virtual keyboard for the time being so that I could login again.  I don't remember what I had done in the first place to switch the login screen to bépo, but now I can't switch it back.    EDIT : In the keyboard settings page, if I click "use system defaults", then everything is in bépo ! Where is this different keyboard layout set ?  ANOTHER EDIT : Here's what did not work :   Changing the layout in settings using the "use system defaults" checkbox in settings sudo dpkg-reconfigure keyboard-configuration changing it in Xconf adding a line in /etc/lightdm/lightdm.conf  sudo dpkg-reconfigure locales slaming head against desk dpkg-reconfigure lightdm sudo gsettings set org.gnome.libgnomekbd.keyboard layouts "['fr']" combinations of the above     Is it possible to relaunch the keyboard configuration tool that's in ubuntu's setup ? The thing has automatic layout detection and it changes the setting everywhere. New tags page mangles tag wiki excerpts I want to split a long equation in many lines I have a long line in equation. I want to split it properly in two or three lines. I've been using \begin{split} and \end{split}, but still it is not in good position. The equation's code is below.  \begin{equation} \begin{split} \frac{r(r-1)c_{0}}{z} + \\ &amp;  \sum_{0}^{\infty}[[(j+r)(j+r+1)c_{j+1} - [(j+r)(j+r-1) - l(l+1)]c_{j}] \\ &amp;= 0, \end{split} \end{equation} Windows losing IPv6 address after ~10 minutes When I initially connect to my home network my windows PC is assigned an IPv6 address - however after a few minutes it loses this address! I seem to have similar behaviour on multiple hosts using both wireless and wired connections.  My router is an Asus RT-AC87U.  How could it be losing the IPv6 address? How can I mintor / diagnose this issue?  Update:  Based on @grawity's suggestion below I ran wireshark on this. Sure enough I see a Router Solicitation message and a Router Advertisment message with a Router lifetime of 600 seconds. After 600 seconds my computer drops its Ipv6 address.  What is supposed to happen? Should my host send another Router Solicitation message? Or should the router periodically resend the Router Advertisment message?  Update 2:    says that Router Adverticement messages should be sent periodically. What is the difference between Θ(n) and O(n)? Sometimes I see Θ(n) with the strange Θ symbol with something in the middle of it, and sometimes just O(n). Is it just laziness of typing because nobody knows how to type this symbol, or does it mean something different? Can I use Stack Exchange logos on a t-shirt or other apparel? I happened to notice while on the Super User site that one user's picture shows him wearing a shirt with the Super User logo on it. Interested, I wanted to find out where he got it from. Looking through old questions on Meta, I found out that there used to be a shop.stackexchange.com site that sold Stack Exchange gear. Unfortunately, they no longer sell any merchandise.  Is there any site where I can purchase a Stack Exchange site shirt/hat/etc.? If not, could I create a shirt/hat/etc. myself with one of the sites' logos on it? If so, where can I locate the logos in their largest size?