i Want to validate a text field in keyup event .  in the field it should accept money type decimal like   (12.23) (.23) (0.26) (5.09) (6.00)  if i enter some wrong value then it should return to the previous value and remove the wrong one
What is the regular expression for a decimal with a precision of 2?  Valid examples:  123.12 2 56754 92929292929292.12 0.21 3.1   Invalid examples:  12.1232 2.23332 e666.76   The decimal point may be optional, and integers may also be included.
When I log in on a Windows 8 machine for the first time with my Microsoft Account (by providing an e-mail address), a new user folder is created:  C:\Users\dzinx_000   In previous versions of Windows, I could choose the name of this folder (it was equal to my username). As I use the commandline often, it is quite annoying to me.    Can I somehow rename it to dzinx?  Does simply renaming the folder break everything? Best method for short time-series Word to describe someone who goes to all the events in town! I'm looking for a short word that could describe people who are always going to every event in town. It doesn't need to be an existing word, feel free to create one of your own. It can also be made of words related to events and parties. (ex: club, event, guest list, etc.)  Edit  The word will serve as a new term to describ these people in a favorable way. It will probably be used for an app name so it need to be catchy and fun. ( Preferably ) Make a div fill the height of the remaining screen space Degrees of freedom in theoretical sample variance (for use in F-distribution) My question is essentially simple: suppose we have a sequence of heads and tails with an apparent chance of getting heads $\hat{p} = 0.5$.      h h t h t t t h t t h ...   How do we tell if this sample was drawn from a binomial distribution with this $\hat{p}$ or if it comes from a combination of different distributions which produces the same average? (e.g. $p = 0.25$ or $p = 0.75$)  Here's what I was thinking of doing:   We chop the sequence into subsections of length $n$, for example $n=5$, and calculate $\hat{p}$ in every such window: {h h t h t}, {t t h t t}, {h ...}0.6, 0.2, ... We then calculate the standard deviation in these $\hat{p}$ values: $\sigma_{ex}=\sqrt{\frac{\sum_{i=1}^M{(\hat{p}_i - \hat{\mu})^2}}{M}}$, where $\hat{\mu}$ is the average $\hat{p}$ and $M$ is the total number of windows of size $n$ we can make.  We calculate the standard deviation in $\hat{p}$ based on a binomial distribution, $\sigma_{th}=\sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$.   Now comes the problem: how to determine if these two values are the same? After a lot of research, I decided to try using an F-ratio test and plugging the result into an f-distribution.  F-ratio: $F = \frac{\sigma_{ex}^2}{\sigma_{th}^2}$ (only valid for normal-distributions :S)  And then an f-distribution to get to a p-value we can check against. However, for the f-distribution I need to know the degrees of freedom in the nominator and denominator. And therein lies my problem: what are the degrees of freedom for the variance calculated from theory? (In the experimental case I think it is M)  If you have this answer or any suggestions on how to solve this problem differently, I would love to hear about it! Can't log in using Firefox in Stack Overflow Here's what is happening; everytime I go to Stack Overflow (stackoverflow.com, NOT meta) with Firefox, it gives me the "Welcome back" tab that pops up from the top. Whenever I click in the "click here to refresh the page" link, all it does is refresh the page without logging me back in.  Even if I try to log in using the "log in" button at the top, all it does is pop up the tab that says "Welcome name here, you're being redirected." The problem is I'm not being logged in, not to mention that it keeps refreshing the page over and over again without giving me a choice to log in with Facebook.  For some reason, I was capable of logging in to Meta Stack Overflow using Firefox. I am still unable to log in to Stack Overflow. Any ideas? Mcrypt extension is missing in 14.04 server for mysql The php mcrypt extension on ubuntu 14.04 shows that it is installed properly, but phpmyadmin says:   The mcrypt extension is missing. Please check your PHP configuration.   My current php config is . If you need anymore information, please contact me through the comments.  $ sudo apt-get install php5-mcrypt     Reading package lists... Done     Building dependency tree            Reading state information... Done     php5-mcrypt is already the newest version.     0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Moved bin and other folders! How to get them back? Combinatorics - binary - very interesting question I tried to solve this problem without any success. I really hope that you will know the answer. $f(n,m)$ presents the number of binary strings (empty string included) that include at most n times '1', and at most m times '0'.      Prove: $$f(n,m) = \binom{n+m+2}{n+1}-1$$ I'd like to be able to select a region (either with a graphical utility or command line) and be able to switch one block type with another, e.g. change all cobblestone in the region to stone. Does a program/mod exist that can do this? Can I read and write to the same file in Linux without overwriting it? How to vertically align underbraces I am trying to balance underbraces in the equation below, how can I ensure that both underbraces at the same depth?  \begin{equation} y = \underbrace{ \left [ x^2 + r^2 (a^2+\frac{a^{0.3}}{b}) \right]}_\text{growth rate} \times  \underbrace{ C_0}_\text{initial} \end{equation} New questions, Show Recommended, Sort Newest not working Select New questions, show Recommended and sort by Newest and the  in my list is from 2012:  EDIT The very old questions now appear to be gone (yay) but the ordering seems inconsistent (boo): The new top bar is out on meta. Consider it a beta EDIT Dec 4 -  We're doing it live! Please post bugs or concerns as questions tagged [top-bar]  We have rolled out our 95% completed top bar for feedback.  Note:   We are still adding a few final features, so if you have a request for a feature that is not there you might hold off on that for a day or two Yes, the bar is black1. Also give that a day or two to sink in.   I also want to specifically address the meta/main/chat links.  I'm very aware that many of you like having the links at the top of the page and that this new version is different.  The thought process behind moving these links is that the "site switcher" should be an automatic place to go when you are on a site and want to go to another one. If you haven't already developed the muscle memory for these links, getting between them required a bit of a cognitive load: You must first decide that you want to switch sites and then you have to decide which area to go to to switch.  Also, we find that less familiar users aren't entirely clear what a standalone link that says "main" or "meta" actually does... Not to mention that it hurts my UX sensibilities that we are dynamically changing links in an element that should be fixed.  It is true that we have added a click in the process, but we have also removed a lot of clicks for other common actions that are much more frequent than switching between main and meta.  All I ask is that you give it a few days and see if the new "switch sites at the top left" paradigm grows on you.  What do you think?  1.  points out that technically it's not quite black. Stopping all automatic updates Windows 10 We've upgraded some machines to Windows 10 and realized there were some updates which updated as required. However, I realized there was no option available to stop the download similar to that on Windows 7 and 8.1. The only way I could stop the download was to stop the Windows Update service.  My question is does anyone know of a way to stop auto updates or is stopping the service is the only solution? Proof of the L'Hôpital Rule for $\frac{\infty}{\infty}$ I ask for the proof of the L'Hôpital rule for the indeterminate form $\frac{\infty}{\infty}$ utilizing the rule for the form $\frac{0}{0}$.   Theorem: Let $f,g:(a,b)\to \mathbb{R}$ be two differentiable functions such as that:  $\forall x\in(a,b)\ \ g(x)\neq 0\text{ and }g^{\prime}(x)\neq 0$ and $\lim_{x\to a^+}f(x)=\lim_{x\to a^+}g(x)=+\infty$ If the limit $$\lim_{x\to a^+}\frac{f^{\prime}(x)}{g^{\prime}(x)}$$ exists and is finite, then  $$\lim_{x\to a^+}\frac{f(x)}{g(x)}=\lim_{x\to a^+}\frac{f^{\prime}(x)}{g^{\prime}(x)}$$  My attempt:  Since $\lim_{x\to a^+}f(x)=+\infty$, $$\exists \delta&gt;0:a&lt;x&lt;a+\delta&lt;b\Rightarrow f(x)&gt;0\Rightarrow f(x)\neq 0$$  Let $F,G:(a,a+\delta)\to \mathbb{R}$, $F(x)=\frac{1}{f(x)}$, $G(x)=\frac{1}{g(x)}$. Then by the hypothesis $\lim_{x\to a^+}F(x)=\lim_{x\to a^+}G(x)=0$, $$\forall x\in(a,b)\ \ G(x)\neq 0\text{ and }G^{\prime}(x)=-\frac{1}{g^2(x)}g^{\prime}(x)\neq 0$$ The question is, does the limit $$\lim_{x\to a^+}\frac{F^{\prime}(x)}{G^{\prime}(x)}=\lim_{x\to a^+}\frac{-\frac{1}{f^2(x)}f^{\prime}(x)}{-\frac{1}{g^2(x)}g^{\prime}(X)}=\lim_{x\to a^+}\frac{g^2(x)f^{\prime}(x)}{f^2(x)g^{\prime}(x)}$$ exist?   The limit $$\lim_{x\to a^+}\frac{f^{\prime}(x)}{g^{\prime}(x)}$$ exists by the hypothesis but we don't know if the limit $\displaystyle\lim_{x\to a^+}\frac{g^2(x)}{f^2(x)}$ exists to deduce that the limit $$\lim_{x\to a^+}\frac{F^{\prime}(x)}{G^{\prime}(x)}$$ exists to use the L'Hôpital Rule for the form $\frac{0}{0}$.  EDIT: After discussing it with other users in the site, we came to the conclusion that this proof is only partial and can't logically be continued to yield the Theorem.  As a result, the rule for the $\frac{0}{0}$ form can't be used to proove the rule for the  $\frac{\infty}{\infty}$ form. Mr. Tavares and myself have already given two different proofs (with the pretty much the same main idea) of the Theorem in question using Cauchy's Mean Value Theorem. You can read them below. You can also read the proof Rudin gives for a stronger version of the Theorem (that does not suppose that $\lim_{x\to a^+}f(x)=+\infty$) in his book Principle of Meathematical Analysis. If you have any objections in either proofs please let me know. Thank you. Why are packages in the official Ubuntu repositories older than the latest (upstream) versions from Debian Sid, PPAs, the authors, etc.? In Java, why do people prepend fields with `this`? When referencing class variables, why do people prepend it with this? I'm not talking about the case when this is used to disambiguate from method parameters, but rather when it seems unnecessary.  Example:  public class Person {             private String name;      public String toString() {         return this.name;     } }   In toString, why not just reference name as name?  return name;   What does this.name buy?   a stackoverflow question whose code has this pre-pending. I am trying to install ia32-libs on Ubuntu 12.04 LTS (x86).  I enabled all the repository sources but I'm receiving the error message below:  ~$ sudo apt-get install ia32-libs   Reading package lists... Done   Building dependency tree          Reading state information... Done   Package ia32-libs is not available, but is referred to by another package.   This may mean that the package is missing, has been obsoleted, or   is only available from another source    E: Package 'ia32-libs' has no installation candidate   output of sudo apt-cache policy ia32-libs    ia32-libs:     Installed: (none)     Candidate: (none)     Version table:     output of cat /etc/apt/sources.list  (removed similar hyperlinks)    deb http://archive.ubuntu.com/ubuntu/ precise restricted main multiverse universe   deb-src archive.ubuntu.com/ubuntu/ precise restricted main multiverse universe #Added by software-properties   deb security.ubuntu.com/ubuntu/ precise-security main restricted universe multiverse   deb-src security.ubuntu.com/ubuntu/ precise-security main restricted universe multiverse #Added by software-properties   deb archive.ubuntu.com/ubuntu/ precise-updates main restricted universe multiverse   deb-src archive.ubuntu.com/ubuntu/ precise-updates main restricted universe multiverse #Added by software-properties Is it possible to transfer Minecraft PE worlds to Minecraft PC?