/\p{Z}/u.test(' ') works on Chrome 71.0.3578.98 and returns true, but on Firefox 65.0 it throws the error: SyntaxError: invalid identity escape in regular expression  Is this a problem with ES implementation in Firefox, or I am using the regex wrong, and Chrome is just being nice and interprets that in the desired way?
What is the easiest way to match non-ASCII characters in a regex? I would like to match all words individually in an input string, but the language may not be English, so I will need to match things like ü, ö, ß, and ñ. Also, this is in Javascript/jQuery, so any solution will need to apply to that.
How do I debug permissions? What is the best regular expression to check if a string is a valid URL? How can I check if a given string is a valid URL address?  My knowledge of regular expressions is basic and doesn't allow me to choose from the hundreds of regular expressions I've already seen on the web. I am running Ubuntu 12.04.1 LTS i686 on VirtulBox. Every time I check the updates, there's a new Linux kernel. If I install the new kernel, I have to install the Virtulbox Guest Additions again and reboot the server. I don't want to do this every week. I know I can manually uncheck the kernel packages from update manager, but is there a way to skip the kernel update automatically? I found an answer here, but it's for Ubuntu 10. Thanks. Both are in the present perfect, but one uses the verb 'to go' and the other 'to be'. Is there a rule for this?  Is there any chance that the differences between "I have been" vs. "I have gone", are differences in English dialect (I don't know if this is the right word).  Edit Could I say that North American English speakers use "I have gone", and maybe U.K speakers say "I've been"? Or vice versa. get emacs to automatically use biber instead of bibtex I was reading the question titled .  In that question, user @PLK mentions that as of auctex 11.87, auctex should automatically check if you are using biblatex and if so, switch to using biber.  I have auctex 11.87 installed and running, but I am not getting this automatic switching behavior.    Say I have two files (borrowed from ).  test.tex  \documentclass{article} \usepackage[backend=biber]{biblatex}  \addbibresource{test.bib} \defbibheading{bibliography}{}  \begin{document}     \nocite{*}     \subsection*{Journal Publications:}     \printbibliography[type=article]      \subsection*{Conference Publications:}     \printbibliography[type=inproceedings]  \end{document}   and test.bib  @ARTICLE{abc,   author = {A Author},   title = {the article title},   journal = {the journal},   year = {2012},   volume = {1},   pages = {1--2},   number = {1},   month = {1},   doi = {1234/5678} }  @INPROCEEDINGS{def,   author = {A Author},   title = {the proceeding title},   journal = {the conference},   year = {2012},   volume = {1},   pages = {11--12},   number = {1},   month = {1},   doi = {5678/1234} }   If I run the following commands:  pdflatex test.tex biber test pdflatex test.tex   I end up with a properly processed document.  In emacs, when I press C-c C-c and select the BibTeX command, emacs runs bibtex test instead of biber test.  I am then greeted with errors about no \citation \bibdata or \bibstyle commands.  My bibtex-dialect variable is automatically getting set to biblatex, LaTeX-biblatex-use-Biber is set to t, TeX-command-Biber is set to Biber, but for some reason TeX-command-BibTex variable is still set to BibTeX.  Should this automatically get changed to Biber?  Do I have to set it using a local variable?  Is this a bug, or am I doing something wrong?  EDIT  According to  in the AUCTeX 11.87 manual:      In case you use biblatex in a document, AUCTeX switches from BibTeX to Biber for bibliography processing.   So I feel like this automatic switch should already be happening. Windows says RAM ran out while there is still 4 GB of physical memory available What is an unsigned char? In C/C++, what an unsigned char is used for? How is it different from a regular char? Properties possessed by $H , G/H$ but not G i) Does there exist a group $G$ with a normal subgroup $H$ such that $H , G/H$ are abelian but $G$ is not ?   ii) Does there exist a group $G$ with a normal subgroup $H$ such that $H , G/H$ are cyclic but $G$ is not ? recover data after using dd command load a file and read the information I want to open an Excel file through an Apex dialog box, then browse the information in my file line and display it with visualforce. I show you my code  public class ImportExcel {       public String fileName{get; set;}     public Blob contentFile{get;set;}     public String[] csvFileLines{get;set;}     public List&lt;String&gt; acclist{get;set;}     public String[] data{get;set;}     public ImportExcel(){         csvFileLines = new String[]{};         acclist = New List&lt;String&gt;();      } public void readFile(){         try         {             fileName=contentFile.toString();         }catch(Exception e){         ApexPages.Message myMsg = new ApexPages.Message(ApexPages.Severity.FATAL,'Please upload a valid CSV document');         ApexPages.addMessage(myMsg);              return ;          }         csvFileLines=fileName.split('\n');          system.debug(csvFileLines);         for(Integer i=0;i&lt;csvFileLines.size();i++){             data=csvFileLines[i].split(',');             acclist.add(data[i]);         }     } }   Once I execute my code, it puts me this error:     13:52:13:012 VARIABLE_ASSIGNMENT   [15]|e|"common.apex.runtime.impl.ExecutionException: BLOB is not a   valid UTF-8 string"|0x4e4728 How do I get the form id of my form? I've just begun to make my modules and I'm at a standstill. I got this code from someone else and am trying to customize it:  function hook_form_alter(&amp;$form, &amp;$form_state, $form_id) {   if ($form_id == 'the form id for the node form') {     $form['#submit'][] = 'my_custom_submit_handler';   } } Custom Login form question In my website have two types people login one is designer another is reader, i want people come to login my website by role. Mean designer go to design login form to login. Reader go to reader login form to login. my question is:   how to show two login forms in same page? how to check the role when the visiter login at the same time in login form? is it any module i can use or i need do something customize the user module and how    customize?   Plz help! URL Rewriting of a query string in php $\{a_n\}$ be a sequence such that $ a_{n+1}^2-2a_na_{n+1}-a_n=0$, then $\sum_1^{\infty}\frac{a_n}{3^n}$ lies in... Let $\{a_n\}$ be a sequence of positive real numbers such that   $a_1 =1,\ \  a_{n+1}^2-2a_na_{n+1}-a_n=0, \ \ \forall n\geq 1$.   Then the sum of the series $\sum_1^{\infty}\frac{a_n}{3^n}$ lies in...  (A) $(1,2]$, (B) $(2,3]$, (C) $(3,4]$, (D)$(4,5]$.   Solution attempt:   Firstly, we figure out what $\frac{a_{n+1}}{a_n}$ is going to look like. We get, from the recursive formula, $\frac{a_{n+1}}{a_n}=1+\sqrt{1+\frac{1}{a_n^2}}$ (remembering the fact that $a_n&gt;0$, the other root is rejected).   We know that, if $\lim_{n \to \infty}\frac{a_{n+1}}{a_n}&gt;1$, then $\lim a_n \to \infty$.   Further, $(a_{n+1}-a_n)= \sqrt{a_n(a_n+1)}&gt;0$. (Again, the other root is rejected due to the same reason).   Hence, $(a_n)$ increases monotonically.   Therefore, the largest value of $\frac{a_{n+1}}{a_n}$ is approximately $1+\sqrt{1+\frac{1}{1}} \approx 2.15$  Now, the sum can be approximated as $\displaystyle\frac{\frac{1}{3}}{1-\frac{2.15}{3}} \approx 1.3$ (In actuality, $\mathbb{sum}&lt; 1.3$).  So, option $(A)$ is the correct answer.   Is the procedure correct?   I have been noticing a handful of this type of questions (based on approximations) lately, and the goal is to find out where the sum / the limit of the sequence might lie.   Is there any "definitive" approach that exploits the recursive formula and gives us the value, or does the approach varies from problem to problem? I know there is something wrong with this but I don't know where. It's some kind of a math fallacy and it is driving me crazy. Here it is: $$-1= (-1)^3 = (-1)^{6/2} = \sqrt{(-1)^6}= 1?$$ I had the Facebook and Instagram apps installed on my iPhone (latest iOS). I deleted both apps and checked that there was no data from either app stored on iCloud (I went to Settings - iCloud - Manage storage and there was no mention of them storing anything on iCloud). Then I reinstalled Instagram, opened it, clicked on Login and the page still showed “Login as MYFACEBOOKNAME”.   How is this possible? How can I delete my FB login info once and for all on my iPhone? Is soaking beans 24 hours unrefrigerated safe? It strikes me as an unsafe food practice to follow Cook's Illustrated's advice for soaking dried beans for 24 hours unrefrigerated.  I've also seen them suggest you soak steel-cut oats unrefrigerated overnight.    Is there some reason why these practices are okay?  Would there be any harm in refrigerating them, particularly the beans, while soaking?  From Cook's Illustrated:     Dissolve 3 tablespoons salt in 4 quarts cold water in large bowl or   container. Add [one pound] beans and soak at room temperature for at least 8 hours   and up to 24 hours. Drain and rinse well. Close Vs Closed and Open Vs. Opened Which board is proper to describe the state of any shop/restaurant?  For instance,     A restaurant with the board Close OR Closed?    A restaurant with the board Open OR Opened?   Well, if I think 'closed' is used when the restaurant is permanently or temporarily closed for more than a day (say for holidays or renovation), what about the conversation mentioned below? It takes -ed even for that day!     "Hey Mike, I forgot my specs at home. Do you see the restaurant there at distance? Is it open?   "Yeah, I do see. But it's closed.   I think open/opened or close/closed here is not a verb. If it isn't, then what is it in those examples? What formats supporting animation are suitable for the web? I have a laptop with Ubuntu installed as the only OS. I also have a USB stick with a Windows 7 installation on it. I want to install Windows from the USB stick on my laptop but when I try to restart the laptop to get access to BIOS, I can't seem to find the command for it, its like it skips everything and just says Ubuntu and then takes me to the login screen.  How do I change the boot priority to USB in Ubuntu?