I am trying to make a registration form in Java that accepts a string in the form of: ok@ok.ok, right now, I have -   (email.matches("[^a-zA-Z0-9]+")   which I need it to also accept @, _,-,. symbols but am unsure how to add it into the regex shown earlier.   As well as this I am aware that there is a way to separate to accept an amount of characters, and then read a specific symbol, (in my case it would be "@" and "." for the email) but am unable to implement it, something along the lines of   (email.matches("[^a-zA-Z0-9]{1-99}[1][@][^a-zA-Z0-9]{1-99}[1][.][^a-zA-Z0-9]+")   Thanks
Over the years I have slowly developed a  that validates MOST email addresses correctly, assuming they don't use an IP address as the server part.  I use it in several PHP programs, and it works most of the time.  However, from time to time I get contacted by someone that is having trouble with a site that uses it, and I end up having to make some adjustment (most recently I realized that I wasn't allowing 4-character TLDs).  What is the best regular expression you have or have seen for validating emails?  I've seen several solutions that use functions that use several shorter expressions, but I'd rather have one long complex expression in a simple function instead of several short expression in a more complex function.
Text in Ubuntu Software Center is unreadable When I do a search in the software center this is what the results look like.    I can only see the text if I select one of them.  I tried changing themes but that didn't fix it. Why do electron and proton have the same but opposite electric charge? What is the explanation between equality of proton and electron charges (up to a sign)? This is connected to the gauge invariance and renormalization of charge is connected to the renormalization of photon field, but is this explanation enough? Do we have some experimental evidence that quarks have 2/3 and -1/3 charges? By the way I think about bare charge of electron and proton. And I am also wondering if this can be explained by Standard Model. sudo apt update always giving Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?) Is gcc 4.8 or earlier buggy about regular expressions? I feel like someone made a comment as an answer on a question with a bounty just so they could reap the "auto bounty" since they are the only answer on it.   I've flagged the bad/useless answer (as a non-answer) for moderator review but the bounty will be assigned automatically in less than 24hrs and I feel like this guy/gal is just trying to cheat the system.   All I'm trying to do is ensure the bounty simply expires and the guy/gal that was trying to cheat the system by putting down a useless guess doesn't get it.   I've answered my own question (properly) and marked it as the accepted answer, not sure if that makes a difference though in this person still cheating the system since I'm the OP and created the accepted answer.   Here is the post: Get the client IP address using PHP I am trying to put two subscripts at the left and right of a character. For example, something like:  _{t} p_{x}  where p is in the middle. How do you do this? Responsive Breakpoints? Twitter Bootstrap uses these break points for responsive design:  Large Display: 1200px Default: 980px Tablet: 768px Mobile: 480px  A client said they are using 1280px for their Large Display breakpoint.  Is there an industry standard for these or are they just made up as we go right now? Are partitions to the inner/outer edge significantly faster Some linux dual/multi-boot tutorials / general partitioning tutorials say that the inner side of a hard disk is faster than the outer side so partitions towards the outside tend to be slower while some say that the exact opposite is true.  Which side is actually faster?  Is the difference noticeable?  How are the partitions physically placed on the disk as compared to the partition listing order-for example gparted shows a logical ribbon layout of the partitions. Are the partitions shown to the left side of this ribbon near the outer or inner edge of the disk physically?  Are there software benchmarks like testing some disk intensive stuff for the first time on identical vanilla installs of the same OS but on different partitions, inner and outer?  EDIT: Links   ctrl + f for "slower" on this page   Says outer side is faster   Says inner side is faster   Says outer side is faster(not about dual-booting) Can I upload an entire folder using FTP? I need to upload a full folder using FTP.  Is there is any option for transferring a folder and all of its contents at once? Window title in bottom of Activities overview is not visible when opening multiple windows Mass and Newton's Second Law series of young adult science fiction books from early 1980s about last of a race of martial experts that sees the destruction of his home planet I remember that the main character is trying to find the group that destroyed his home planet while he was on a mission. His planet was very difficult to live on and the people became expert in martial arts and were the best soldiers in the galaxy. They were mercenaries and often helped against tyrants. There was a very memorable section in at least one book about an initiation task that the main character had to do in that he had to survive in their wilderness for days. He was at some point surrounded in a old building by thousands of poisonous worm/snake creatures that he managed to survive until rescued by the leaders. In the new header could we please move the chat link back to where it was? (One click away)  As a daily frequent to the JavaScript room that's the one link I'd love to have visible 100% of the time.  Aside from that, I actually love the new header. (Maybe take it a step further an add a customizable header with (X) link spots for your most used links?)  Just my thoughts What is the best way to determine the number of days in a month with JavaScript? I've been using this function but I'd like to know what's the most efficient and accurate way to get it.  function daysInMonth(iMonth, iYear) {    return 32 - new Date(iYear, iMonth, 32).getDate(); } As the title suggests, I have some kit which is 200m from our current infrastructure (outdoors).  What is the cheapest way to establish a reliable connection across a 200m stretch (Cat 5e ethernet only works up to about 100m from our tests)? MATLAB superclass can not be found on the MATLAB's search path Why does an environment's label have to appear after the caption? \documentclass{article} \usepackage{algorithm}  \begin{document} \setcounter{section}{54} \section{A section with no label} \begin{algorithm} \label{myalg} \caption{An algorithm with the label `myalg'.} \end{algorithm} Reference to myalg: \ref{myalg}. \end{document}   With this code, the reference givens 55 (the section number); if I move the label after the caption command, I get the correct reference (1).  Why should this be the case? I find it confusing: when thinking about an algorithm as an environment, you expect to be able to label it right after you began it. At the very least I would expect some kind of error or "??" to appear, rather than the previous environment or reference-able entity being used. How to prove that exponential grows faster than polynomial? In other words, how to prove:  For all real constants $a$ and $b$ such that $a &gt; 1$, $$\lim_{n\to\infty}\frac{n^b}{a^n} = 0$$  I know the definition of limit but I feel that it's not enough to prove this theorem. Compression API on the iPhone