Why does a "&&=" Operator not exist?
Why doesn't Java have compound assignment versions of the conditional-and and conditional-or operators? (&&=, ||=)
Can bug reports and feature requests requiring SE Dev attention be reported on per-site metas, or do they need to all go here? I use Stack Overflow a lot and have noticed a certain trend that I myself got caught up in at one time of using the phrase "I am having a problem" in place of "I have a problem."  I would use this phrase for an event in the future, for example, "I am having a steak dinner tonight," but for a problem that I need solved and am asking for a solution, I'd use "I have a problem..."   What would force us to use this phrase? Is it even valid English for the present tense? Why can't $ i\hbar\frac{\partial}{\partial t}$ be considered the Hamiltonian operator? In Java, for a string x, what is the runtime cost of s.length()? Is it O(1) or O(n)? I've been told that code such as:  for (int i = 0; i &lt; x.length(); i++) {     // blah }   is actually O(n^2) because of the repeated calls to x.length(). Instead I should use:  int l = x.length(); for (int i = 0; i &lt; l; i++) {     // blah }   Is this true? Is string length stored as a private integer attribute of the String class? Or does String.length() really walk the whole string just to determine its length? ISP blocking port 25 I'm trying to run this command in the terminal:  sudo apt install software-properties-common   This is the error message I get:  E: Could not get lock /var/lib/dpkg/lock-frontend - open (11: Resource temporarily unavailable)   E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend),     is another process using it? How can I rename many files at once? I need to rename a bunch of files in order to fix their sort order, therefore I need to be able to do a sort of "find and replace" so I can replace chunks of the filenames at a time.  What tools should I use? I prefer GUI but a command line tool recommendation would also be fine. Askers should be able to close their own question as a duplicate How do I go about backing up/saving installed device drivers in Windows? I want to reinstall Windows on a machine which has some very obscure drivers. I don't much fancy having to hunt round for them (that's if I'm able to locate them at all). Is it possible to save or backup already installed drivers? If so, how do I do this? How do I then go about installing these 'saved' drivers? I know base 2 and base 10 , MB and MiB, but i'm not understanding the byte counts shown for a directory, by du and by windows explorer The du command shows 43G in use. I'm not sure whether that's base 2 in the sense of 2^30 or if it's base 10, in the sense of 10^9.  But anyhow -   Running this du command from cygwin, to see the size of the windows directory (done from an administrative command prompt - since it seemed to have some issues reading some directories otherwise)  user@comp ~ $ du -sh /cygdrive/c/windows 43G     /cygdrive/c/windows   Windows Explorer  which I understand shows it in 'base 2', (a larger unit for KB,MB,GB than base 10 KiB, MiB e.t.c.), and hence a lower quantity of that larger unit is required to give the same result.    Windows explorer shows      46.6GB  , over 50 billion bytes.    (according to windows explorer)  or  46.8GB  , over 50 billion bytes. (according to windows explorer)  So, du aside.  Even if I multiply the larger figure, 46.8GB  by 1.048576 then I get 49.0733568 that's not over 50 billion. So that's part A of the question,  but then also, part B of the question, why is the du figure so low. Bounding box is larger than expected when drawing a curved path I have been working on logo for my department and I have the following code. The problem is that whenever I compile the diagram seems to be larger than the actual logo. I do not know what is the problem. I know the numbers I have selected are not the best but any insights into the matter will be highly appreciated.   \documentclass[letterpaper]{article}  \usepackage[top=2cm,bottom=2cm,left=2cm,right=2cm]{geometry}  %\usepackage{amsmath,amssymb,units}  %\usepackage{enumitem,multicol}  \usepackage{tikz}  %\usetikzlibrary{arrows}  \usepackage{lipsum}   \begin{document}   \lipsum[1-2]  \begin{tikzpicture}[y=0.80pt, x=0.8pt,yscale=-1]  \path[draw=black,fill=white]    (258.9527,290.5199) .. controls (173.9885,538.4766) and (568.5860,261.2969) ..    (306.5098,257.1141) .. controls (44.4337,252.9312) and (429.9845,542.5624) ..    (352.9767,292.0206) .. controls (275.9689,41.4788) and (119.6549,497.6604) ..    (334.1376,346.9999) .. controls (548.6203,196.3394) and (66.4622,188.6439) ..    (276.0276,346.0724) .. controls (485.5930,503.5010) and (343.9169,42.5633) ..    (258.9527,290.5199) -- cycle;  \end{tikzpicture}  \lipsum[1-2]  \end{document}    See image below: Hey guys I found one or two papers which use ridge regression (for basketball data). I was always told to standardize my variables if I ran a ridge regression, but I was simply told to do this because ridge was scale variant (ridge regression wasn't really part of our course, so our lecturer skimmed through it).  These papers I read didn't standardize their variables, which I found a bit surprising. They also ended up with large values of lambda (around the 2000-4000 level) via cross-validation, and I was told that this is due to not standardizing the variables.  How exactly does leaving the variable(s) unstandardised lead to high lambda values and also, what are the consequences of not standardizing the variables in general? Is it really such a big deal?  Any help is much appreciated. List has no row exception: Queryerror I have below line placed in controller that fires list has no row exception. I just need to show a custom message instead when the query returns no value.   Apex code:  Id CI=[select Compliance_Incident_abv__c from Compliance_Incident_Transaction_abv__c where Name=:selectedCIT].Compliance_Incident_abv__c ;  //**This line throws error**     system.debug('CI@@'+CI);         if(cond != '')             cond += ' and';           else             cond += ' where ';                                        if(CI!=null)          cond += ' Id = \'' + CI+ '\''; How to access a SQL Server database from other computer connected to the same workgroup? Why does the reputation need to be publicly displayed? Possible Duplicate:          The idea of getting greater privileges with greater reputation is good, but what is the benefit of publicly displaying that reputation? Since SO claims to be about good questions and answers, that purpose is better served if the reputation is only visible to the account owner (and, of course, the site admins). This would better ensure that content gets pushed up solely by its merit, and not based on the author. (See )   Edit (copied from comment to an answer below): Once you have gathered high reputation, you can also gather more reputation with ordinary answers, especially from newbies (newbies on the topic, not on the site) who usually choose to accept or upvote an answer on the assumption that "since a high-rep user has posted it, it is probably right". Can you guarantee that doesn't happen often? What is the difference between linear equation and linear regression? I am using linear equation to find the correlation of values of x, y and z  3x + 4y + 2z = 6 4x + 1y + 4z = 17 8x + 2y + 5z = 9   I would like to know the difference between linear equation and linear regression. Is it the same in approach? How to remotely display my Android on my PC? There is a thing which is called miracast, it can mirror the display of the Android phone to another monitor, but my screen doesn't have this function, am I possible to do it in Ubuntu? I have a spreadsheet full of addresses to geocode in ArcMap 10.  I've added the spreadsheet to the map, then started to geocode them via the context menu's "Geocode addresses" item.  Many were matched automatically, and most of the unmatched I've been able to resolve within the Interactive Rematch dialog. But I have a handful of addresses where I get no result at all.  I can, however, locate these points on Google Maps, and I can get the latitude and longitude that way.  How can I enter that data into the table to locate the missing points?  I have tried editing the data and putting the lat/lon values into the X and Y columns, (via Edit Features -> Start Editing, then Open Attribute Table on the context menu).  But when I Flash the point, I don't see it.  The lat &amp; lon are consistent with the other data points on the map (i.e., not swapped, and using the correct sign).  How can I add the points to the table? Fibonacci combinatorial identity: $F_{2n} = {n \choose 0} F_0 + {n\choose 1} F_1 + ... {n\choose n} F_n$ Can someone explain how to prove the following identity involving Fibonacci sequence  $F_n$  $F_{2n} = {n \choose 0} F_0 + {n\choose 1} F_1 + ... {n\choose n} F_n$ ? If $a^2+b^2+c^2=1$ then prove the following.