Array rotation with python (90 degree clockwise)- Having issues with understanding list copies
List of lists changes reflected across sublists unexpectedly
Turning off Twitter Bootstrap Navbar Transition animation Ubuntu 18.04 hangs on booting with message "started user manager for uid 120" on Asus 1015PX I installed Ubuntu 18.04 amd64 desktop on Asus Eeepc 1015px, but it hangs on booting. The last message is 'Started User Manager for UID 120'.  I managed to boot up in recovery mode and finished the installation with 'sudo apt-get upgrade', but nothing has changed.  Does anybody know how I can tackle it?  Thanks in advance, Newton. What is the alternative for Teamviewer? Is there any Ubuntu alternative for team-viewer software for Windows? Suppose we have two functions, $f:X\rightarrow Y$ and $g:Y\rightarrow Z$. If both of these functions are onto, how can we show that $g\circ f:X\rightarrow Z$ is also onto? I'm using TikZ to plotting some functions for a document. For example, I want to plot 1/(x+1). So I did something like this:  \begin{tikzpicture}[&gt;=stealth,x=3mm,y=3mm] \draw (0,5) node[above]{\fimg $y=f(x+1)=\dfrac{1}{x+1}$}; \clip (-5,-5) rectangle (5,5); \ejes[1]{-4}{4}{-4}{4} \draw[samples=100] plot(\x,{1/(\x+1)}); \end{tikzpicture}   where \ejes[style]{xmin}{xmax}{ymin}{ymax} is command, that I have defined before to draw the axes (join with \fimg). My expected output for the code below was just the function, but I get this:    So, TikZ automagically put the vertical asymptote at x=-1. That isn't a bad thing, but now I want to have some control over it. For example I want dotted lines for vertical asymptotes. How can I do that? Fix half-installed package I am getting error while using sudo apt-get upgrade stating:  dpkg: error processing libgfortran3:amd64 (--configure):   package libgfortran3:amd64 is not ready for configuration   cannot configure (current status `half-installed') Errors were encountered while processing:   libgfortran3:amd64 E: Sub-process /usr/bin/dpkg returned an error code (1)   It does not seem to block the installation/upgrade other applications. I believe this problem arose due to direct shutting down of my PC while the application was being upgraded.  How can I fix this? How to split a file according to a column (including header) and rename the generated files? I have a .txt that can be exemplified like this:  NAME | CODE name1 | 001 name2 | 001 name3 | 002 name4 | 003 name5 | 003 name6 | 003   I need to write a script to split this file according to the CODE column, so in this case I'd get this:  file 1: NAME | CODE name1 | 001 name2 | 001  file 2: NAME | CODE name3 | 002  file 3: NAME | CODE name4 | 003 name5 | 003 name6 | 003   According to some research, using awk would work:  $ awk -F, '{print &gt; $2".txt"}' inputfile   The thing is, I also need to include the header to the first line and I need the file names to be different. Instead of 001.txt, for example, I need the file name to be something like FILE_$FILENAME_IDK.txt. How do I install PlayOnLinux on Ubuntu? When to pull loose teeth My 5 year old is starting to have some teeth become loose. Specifically her lower two front teeth. I just noticed today that one of them is really loose. However, I don't know how loose it should be before pulling it out.  I'm also curious about how to pull them (or should I just let them fall out, which seems bad). My father pulled mine with pliers but I think my wife would freak out if I tried to do that.  So, how loose is lose enough and how to pull them out (technique, tools, etc.). Vertical alignment in table: m-column, row size - problem in last column I recently traveled from the Basel area to Stuttgart for a weekend.  I had round-trip tickets including (paid) bicycle reservations.  At our first station change, we found that our EC train was canceled.  Information gave us a replacement train schedule, using slow RE trains which don't require reservations for bicycles.  As we continued our trip, every single train we boarded arrived late, eventually causing us to reach Stuttgart roughly 2 hours later than our initial itinerary.  What monetary compensation am I justified in requesting from Deutsche Bahn in this case?  In particular:   It seems clear I should get back the bicycle reservation money, since the train we reserved on was canceled. I know DB offers compensation for late travels.  I'm not sure whether we were 2 hours late or more, or just shy of 2 hours.  But does this apply if we weren't traveling by our original trains? If we had originally scheduled our journey with RE trains and other local transport, we could have bought a Baden-Württemberg ticket for much cheaper than our tickets including an EC cost.  Can I ask them to refund the difference? Am I entitled to any other type of compensation? Show $$\frac{(2n)!}{n!\cdot 2^n}$$ is an integer for $n$ greater than or equal to $0$.   Could anyone please help me with this proving? Thanks! What's the difference between :: (double colon) and -> (arrow) in PHP? Confusion in symbol of subset. If every element of set A ia an element of set B then we say that A is subset of B. A is said to be proper subset if A does not equal B.  My question is - whether the symbol we use to show subset is  same as that for proper subset? I have seen that A is subset of A itself is shown by the same symbol as that for the subset while when we write improper subset, we usually write equal to sign with symbol of subset. So, please help me to know this. Understanding the proof for $\gcd (F_n, F_{n+k}) = 1$ where $F_n$ is a Fermat number I'm trying to understand the following proof of why      No two Fermat numbers have a common divisor greater than $1$.   Hardy and Wright show the following proofs:   If $x = 2^{2^n}$, we have  $$\frac{F_{n+k} - 2}{F_n}(\circ) = \frac{2^{2^{n+k}}-1}{2^{2^n}+1} = \frac{x^{2^k}-1}{x+1} = x^{2^k-1} - x^{2^k-2} + \ldots -1$$  The main issue I'm having is the $\circ$ part. I don't understand how they get that. The rest of the proof makes sense but the first part is really confusing me. Can someone please explain where they get that fraction?  Thanks a bunch! Writing test code for wrapper class I created a controller which looks like this  public with sharing class EventRegistrationController {      // A CONTROLLER FUNCTION     // FUNCTION RETURNS A LIST OF cSession      public List&lt;cSession&gt; getSessions() {            //DO STUFF       }     //A PUBLIC CLASS WITHIN CONTROLLER    @TestVisible public class cSession      {         public Session__c con {get; set;}         public Boolean selected {get; set;}          //This is the contructor method.          public cSession(Session__c c) {              con = c;             selected = false;         }     }  }   I need to write a test code for the controller, how can I create a list of cSession and call getSession function? biblatex in a nutshell (for beginners) Is there a 'biblatex in a nutshell' guide out there? I'd like if someone explained to me the essentials on how to use biblatex (what lines I have to write in my document, which files I have to have, how many times and what I have to compile), so then I can go to  to customise it further. How to reach local computer via machine name instead of IP? Developer here prototyping a mobile app, somewhat new to mobile:   I have a simple HTTP service running (currently) on my main laptop with machine name latitude. Another laptop named vaio sharing the same WiFi network can access that service via http://latitude:8080 -- in other words, it can easily resolve the (current) IP 192.168.x.y (or whatever dynamic IP it has at that moment) of latitude somehow. Now my HTC Android phones, connected to the same WiFi network, can reach the IP address of latitude so opening in its browser http://192.168.x.y:8080 works. But I'd like to use the machine name here, too, like when I access the HTTP service from vaio, simply by typing http://latitude:8080 and have the phone resolve the current dynamic IP of latitude. This doesn't work, only get the standard browser error page: "Webpage not available".   Is there some DNS setting in Android I need to tweak? Haven't found anything from playing around with Settings, and a question like this is notoriously hard to google, too...  The One V has Android 4.0, and the One M7 has Android 4.2 in case that makes a difference.  (Note, this should work even when the Android is not USB-connected to my computers and is not acting as a WiFi Hotspot -- obviously, since it's consuming my main WiFi network anyway). When I dock my Windows 7 laptop, I want it to prefer the wired ethernet connection over WiFi.  This is a pretty straightforward thing to do on my Mac - I just reorder my network preferences, and it "does the right thing." I just can't figure out how to achieve the same thing on my Win7 laptop.  So, when I'm docked, it connects to WiFi, and then fails to connect to servers on the local wired network. How do I fix this? How exactly does curved space-time describe the force of gravity? I understand that people explain (in layman's terms at least) that the presence of mass "warps" space-time geometry, and this causes gravity. I have also of course heard the analogy of a blanket or trampoline bending under an object, which causes other objects to come together, but I always thought this was a hopelessly circular explanation because the blanket only bends because of "real" gravity pulling the object down and then pulling the other objects down the sloped blanket. In other words, to me, it seems that curved space wouldn't have any actual effect on objects unless there's already another force present.   So how is curved space-time itself actually capable of exerting a force (without some source of a fourth-dimensional force)?  I apologize for my ignorance in advance, and a purely mathematical explanation will probably go over my head, but if it's required I'll do my best to understand.