multi variables in python like $$var in PHP
How do I create variable variables?
Mathematica not plotting whole logarithmic function Proving that a number with digits 1...9 in some order, ending in 5, is not a perfect square. If "x" is a 9 digit number , which contains digits from 1 to 9 which ends in 5 . Prove that it can't be a perfect square ( digits are not to be repeated).  Please suggest the solution of this question. What is a "Swap Area"? So I noticed this question has not been asked directly;  What is this "Swap Area" people keep referring to when it comes to installing Ubuntu? I lost my house in minecraft. How can I find it? I was in creative mode on minecraft PE. I made this really awesome house plus a hotel! I was finishing up my house but decided to explore first. I explored for about 10 minutes and then stopped. Suddenly, I started worrying because I didn't know where I was. I couldn't find my house on a map, a compass, and I didn't make a beacon or keep track of what side of the sun it was on either. How can I find my house again??? When compiling a beamer presentation and using the following \author command  \author{Name \\ \texttt{my.email@domain.com}}   I get the following hyperref warning in my logfile  Package hyperref Warning: Token not allowed in a PDF string (PDFDocEncoding): (hyperref)                removing `\\' on input line 15.   Package hyperref Warning: Token not allowed in a PDF string (PDFDocEncoding): (hyperref)                removing `\new@ifnextchar' on input line 15.   I understand that this has to do with hyperref setting the PDF metadata, where the linebreak does’t make much sense and should be removed.  Trying to set  \hypersetup{pdfauthor={Name}}   does’t change the situation, seems like hyperref is still looking at the author command.  How do I get the desired display of author name with email and still keep hyperref happy? Can 12 teams in 6 disciplines play 6 rounds without repetition? How should I deal with becoming discouraged as a graduate student? Who is bound to the Prime Directive? Status of B1/B2 visa after citizenship change? Visiting Iran as a dual EU-American citizen How do shock waves form in space? Today my aerodynamics professor mentioned that the equations we were learning for atmospheric shock waves can also be applied by astrophysicists to study black hole-related shock waves in space.  How is this possible? Isn't space too rarefied for shock waves? What is an example application? He mentioned something about the density limit before/after a relativistic shock approaching 6. How do I get a substring of a string in Python? Is there a way to substring a string in Python, to get a new string from the third character to the end of the string?  Maybe like myString[2:end]?  If leaving the second part means 'till the end', and if you leave the first part, does it start from the start? Forcing SSL and www in .htaccess I'm looking for a way to force SSL and www.  I've been able to force both separately but together I keep running into redirection issues. The following code works when handling a URL in this format: http://example.com and properly redirects to https://www.example.com but when the incoming URL is https://example.com it will not forward to https://www.example.com - Any suggestions?  EDIT: it should also send http://www.example.com to https://www.example.com.  RewriteCond %{REMOTE_ADDR} !127\.0\.0\.0 RewriteCond %{SERVER_PORT} 80 RewriteCond %{HTTP_HOST} !^www.example\.com$ RewriteRule ^(.*)$ https://www.example.com/$1 [R,L] An incorrect proof by exhaustion How to create python bytes object from long hex string? Java socket/serialization, object won't update I know someone or the other has asked about disabling ⌘Q, but I like the shortcut, and I use it often. However, I use an email client called Airmail that unfortunately does not keep a service (for notifications) running in the background when it is quitted. However, if I press the close button a service runs in the background, allowing me to receive notifications.  But since I have a habit of pressing ⌘Q all the time to close apps, I was looking into a way I could disable it for only Airmail.  Anyone know of a what to do this? Wrap text at any point if normal hyphenation not possible I have data (generated from a database, not manually typed in) that mostly fits into a table cell with fixed width, but sometimes overflows because there are long words for which no hyphenation is found.  The problem can be demonstrated with the following example:  \documentclass{article} \usepackage[utf8]{inputenc} \begin{document} \begin{tabular}{|p{1cm}|p{4cm}|} 1 &amp; Cell where normal hyphenation is possible ÄÖÜ \\ 2 &amp; CellwherenormalhyphenationisnotpossiblebutshouldwrapinsteadofoverflowÄÖÜ \end{tabular} \end{document}   My requirements are:   Text never overflows the cell (assuming some minimum width such that at least a handful characters have place) First priority measure to achieve 1. is the normal hyphenation If 2. fails, it is allowed to break the word at any character, so fill the line and break just before overflow would happen (disregarding normal hyphenation rules)   In the example, the overflow in cell 1 is prevented by measure 2., the normal hyphenation. The second cell overflows. I would like to have this cell treated by measure 3.  For the answer please consider:   Package seqsplit didn't help me The custom macro \wrap proposed in the answer to  comes near my wish, but can't handle the non-ascii characters ÄÖÜ (independent if they are input with utf8 input encoding or with \"A\"O\"U) As the text comes from a database, no manual editing of the cell content is wanted.   One of my ideas was to insert \linebreak[0] after every character, to tell LaTeX that a break can be made if no better opportunities exist. But this doesn't work like intended.  Thanks for your suggestions! Is a NVIDIA GeForce with Optimus Technology supported by Ubuntu? I am considering buying a Dell XPS 15 laptop. The laptop has a Nvidia 420m card which should work with Linux but I keep reading that the Nvidia Optimus technology isn't supported on Linux. I am not really interested in switching from Nvidia to Intel to save power but need to know that the Nvidia card will in fact work if I installed Ubuntu.  If anyone has experience using a Nvidia card with Optimus technology or even better the exact laptop in question (Dell XPS 15 with 1GB NVIDIA® GeForce®  GT 420M) it would be great.  A major problem holding people back from adopting Linux is this sort of hardware issue. I am a long term Ubuntu user and supporter who can't afford to make a mistake with a purchase like this. I don't want to spend £500+ to find I have no graphics acceleration because Windows 7 is not an option. Looking for sci-fi short story anthology with a particular story of an Earth/Mars war children inheriting the surface I read this in the early to mid 80's.  It was a textbook sized hardcover anthology with color illustrations throughout.  Each story had a few images, some were full page illustrations.  The particular story I remember the most involved Earth survivors living underground.  Robots controlled the war from the surface.  A teenage girl and boy decided to sneak away to the surface as no one had been up there in a long time.  The kids discover greenery and a healthy environment, with rusted robot guardians.  The robots had been keeping the humans fooled that the war was still going on, and had kept them under the surface.  Mars had been wiped out from nearly the first volleys of missiles.    The robots judge the teenagers as worthy and let them remain on the surface.  The kids had silver jumpsuits that dissolved when they got wet.  The robot illustrations were blocky, almost weathered stone-like statues.  They had nearly spherical feet and square simple heads.  The faces had eyes and simple mouths.  -edit- The robots were similar in shape to the one in this picture, but smoother, and no arms.  The illustrations with them had the robots being several stories tall.  I kind of remember that the kids emerged from the belly of one or something like that.