Grouping list element in C#
A method to count occurrences in a list
I have a really strange situation here. My PC works fine, at least in most cases, but there's one thing that I can't deal with. When I try to copy a file from my pendrive, everything is ok -- I got 16-19M/s , it works pretty well. But when I try to copy something to the same pendrive, my PC freezes. The mouse pointer stops moving for a sec or two, then it moves a little bit and it stops again. When something is playing, for example, in Amarok, the sound acts like a machine gun. The speed jumps from 500K/s to 15M/s, average 8M/s. This occurs only when I'm copying something to a pendrive. When the process of copying is done, everything backs to normal.   I tried everything -- other pendrive, a different USB port on front panel or those ports from back, I even changed the USB pins on motherboard (front panel), but no matter where I put my USB stick, it's always the same. I tried different filesystem -- fat32, ext4. I have no problem with the device on Windows, on my laptop. It has to be my PC or something in my system. I have no idea what to look for. I'm using Debian testing with standalone Openbox. My PC is kind of old -- Pentium D 3GHz, 1GiB of RAM, 1,5TB WD Green disk. If you have something that would help me to solve this issue, I'd be glad to hear that.  I don't know what else info I should provide, but if you need something, just ask, I'll update this post as soon as possible.  I tried to reproduce this problem on ubuntu 13.04 live cd. I mounted my encrypted partition + encrypted swap and connected my pendrive to a usb port. Next I tried to start some apps, and now I have ~820MiB in RAM and about 400MiB in SWAP. There's no problem with copying, no freezing at all, everything is as it should be. So, it looks like it's a fault of the system, but where exactly? What would cause such a weird behavior? multiple definition error including c++ header file with inline code from multiple sources I have a c++ header file containing a class. I want to use this class in several projects, bu I don't want to create a separate library for it, so I'm putting both methods declarations and definitions in the header file:     // example.h #ifndef EXAMPLE_H_ #define EXAMPLE_H_ namespace test_ns{  class TestClass{ public:     void testMethod(); };  void TestClass::testMethod(){     // some code here... }  } // end namespace test_ns #endif   If inside the same project I include this header from more than one cpp file, I get an error saying "multiple definition of test_ns::TestClass::testMethod()", while if I put the method definition inside the class body this does not happen:  // example.h #ifndef EXAMPLE_H_ #define EXAMPLE_H_ namespace test_ns{  class TestClass{ public:     void testMethod(){         // some code here...     } };  } // end namespace test_ns #endif   Since the class is defined inside a namespace, shouldn't the two forms be equivalent? Why is the method considered to be defined twice in the first case? How can I make a rounded indentation on a cylinder? I'm trying to do a cosmetic bottle in blender but i don't how to do this thing in the image. How to do this round edge on the cap. Can anyone help me? My book uses the argument that the multiplicities of a few macrostates in a macroscopic object take up an extraordinarily large share of all possible microstates, such that even over the entire lifetime of the universe, if each microstate had an equal chance of being accessed, fluctuations away from equilibrium would never occur.  My question to this statistical proof is this: In the real world, is there really an infinitesimal but nonzero chance that macroscopic systems could access some of the more unlikely macrostates (e.g. heat transfer from a cold object to a hot object)? ‘[...][Harry'll] be famous – a legend – I wouldn’t be surprised if today was known as Harry Potter Day in future – there will be books written about Harry – every child in our world will know his name!’   ‘Exactly,’ said Dumbledore, looking very seriously over the top of his half-moon glasses. ‘It would be enough to turn any boy’s head. Famous before he can walk and talk! Famous for something he won’t even remember! Can’t you see how much better off he’ll be, growing up away from all that until he’s ready to take it?’   Philosopher's Stone - pages 15 - 16 - chapter one, The Boy Who Lived   Did Dumbledore choose correctly?  Knowing what we do about Harry and his canon character attributes (And faults, too!), was Harry really better off enduring eleven years of physical and emotional abuse at the hands of the Dursleys than eleven years of celebrity and fame in the wizarding world? I'm sure we've all read about child celebrities who have done well handling fame, and some who have not fared so gracefully.   Would Harry have endured celebrity as stoically as he did the Dursleys' abuse? Did Dumbledore make the right choice in leaving Harry with the Dursleys instead of letting him grow up in the wizarding world?  Was Harry really better off?  ETA: I'm looking for an answer grounded in Harry Potter canon and written in the spirit of canon. Please do not pair Harry with Elle Fanning or opine that he's secretly an American ;) Thanks! This is a question you can read everywhere on the web with various answers:  $ext = end(explode('.', $filename)); $ext = substr(strrchr($filename, '.'), 1); $ext = substr($filename, strrpos($filename, '.') + 1); $ext = preg_replace('/^.*\.([^.]+)$/D', '$1', $filename);  $exts = split("[/\\.]", $filename); $n    = count($exts)-1; $ext  = $exts[$n];   etc.  However, there is always "the best way" and it should be on Stack Overflow. I think some good words would be conflicted, or confused. As an example of context, think of someone who believes in freedom of speech, but, at the same time, they would support banning comedians who make jokes about certain issues that person cares about. Using relative paths for Windows shortcuts Error validating geometry collection / multipolygon in PostGIS Book: Nanobot apocalypse on Earth, originally used for weather control A few years ago I read an excellent sf book about nanobots that went out of control. In the book they were used for weather control, when they went amok the scientists threw in yet another bunch of nanites and so on, until Earth became uninhabitable, teeming with nanites, I remember the weather also became cold. The planet still could be visited but when they lost cloaking the nanites would attack.   Also, some humans in the book merged with nanites, they could behave benevolently but I forgot the plot too. I only remember fragments of this book, I would like to read it again in English. (loaned a long time ago from a library here in Sweden but they closed the library).   I only know that it was written by an Anglo-American contemporary SF writer, probably 30-55 y.o. Prove that $1+\frac{1}{3}+\frac{1\cdot 3}{3\cdot 6}+\frac{1\cdot 3\cdot 5}{3\cdot 6 \cdot 9}+.........=\sqrt{3}$ Prove that $$1+\frac{1}{3}+\frac{1\cdot 3}{3\cdot 6}+\frac{1\cdot 3\cdot 5}{3\cdot 6 \cdot 9}+.........=\sqrt{3}$$   $\bf{My\; Try::}$ Using Binomial expansion of  $$(1-x)^{-n} = 1+nx+\frac{n(n+1)}{2}x^2+\frac{n(n+1)(n+2)}{6}x^3+.......$$  So we get $$nx=\frac{1}{3}$$ and $$\frac{nx(nx+x)}{2}=\frac{1}{3}\cdot \frac{3}{6}$$  We get $$\frac{1}{3}\left(\frac{1}{3}+x\right)=\frac{1}{3}\Rightarrow x=\frac{2}{3}$$  So we get $$n=\frac{1}{2}$$  So our series sum is $$(1-x)^{-n} = \left(1-\frac{2}{3}\right)^{-\frac{1}{2}} = \sqrt{3}$$  Although I know that this is the simplest proof, can we solve it any other way someting like defining $a_{n}$ and then use Telescopic sum.  Thanks. Is there a way to set an "Adventure Mode Boundary" in Minecraft?  I am trying to create this village where players can spawn in, and then set out to explore the world and build and do normal minecraft stuff. I don't want them to destroy this village, so I want them to be in adventure mode when they are in the village and then switch them to survival when they leave, and vice-versa. When they return to the village, they get switched back to adventure mode.  In other words, I want to set an "Adventure Mode Boundary" to protect buildings. I am working without mods. I am hoping there is an simple way using command blocks. What is $dx$ in integration? When I was at school and learning integration in maths class at A Level my teacher wrote things like this on the board.  $$\int f(x)\, dx$$  When he came to explain the meaning of the $dx$, he told us "think of it as a full stop".  For whatever reason I did not raise my hand and question him about it.  But I have always shaken my head at such a poor explanation for putting a $dx$ at the end of integration equations such as these.  To this day I do not know the purpose of the $dx$.  Can someone explain this to me without resorting to grammatical metaphors? How to remove zsh alias? I have an alias which is predefined by an oh-my-zsh plugin.  -&gt; % alias gcm gcm='git checkout master'  I'd like to remove it, i.e. I'd like alias | pcregrep "\bgcm\b" return 1. I've tried with alias gcm='' but after that the alias is still existent. "There Is"/"There are" depends on plurality of the first list element or not? For a more comprehensive list of monitoring tools and their features, check out .   As the question states, what are the most commonly used tools used for this task and what are their strengths and weaknesses? "Home page" or "homepage"? Is there a convention for the spelling of the name of the main page of a website? Should it be home page, with a space between the two words; or homepage, all one word? I'm new at Linux and I just download Ubuntu 12.04 LTS.  I found a spot that showed me how join my Windows Active Directory.  It has me add couple lines into the 'hosts' but I'm not able to edit the file because I do not have the permission.  I'm not the owner.  I use chmod with it rwx and still it will not let edit the file.  How do you change the permission?  Thanks Is there a possibility to change the font-style in the table of contents? Everything I wrote down in my document was written with Times. However, the ToC does not have the same font family. Is there a way to change the font of the ToC to Times New Roman? Thank you : )    \documentclass[a4paper, fontsize=11pt]{scrbook} \usepackage{geometry} \geometry{a4paper, top=25mm, left=25mm, right=25mm, bottom=20mm, headsep=10mm, footskip=12mm}  \usepackage[ngerman]{babel}  \usepackage[T1]{fontenc}        \usepackage[latin1]{inputenc} \usepackage{acronym}      \usepackage{anyfontsize}  \begin{document}  \tableofcontents  \chapter{Test} Is there a possibility to change the font-style in the table of contents? Everthing I wrote down in my document was written with Times. However, the ToC does not have the same font family. Is there a way to change the font of the ToC to Times New Roman?  \end{document} Show that $\mathbb{E}(T) = \sum\limits^\infty_{k=1}\mathbb{P}(T \geq k)$ for $T$ nonnegative integer valued and $E[T] < \infty$ Let T be a non-negative integer-valued random variable with $\mathbb{E}(T) &lt; \infty $. Prove that $\mathbb{E}(T) = \sum^\infty_{k=1}\mathbb{P}(T \geq k)$.  Had a few attempts, haven't really got anywhere. I'm wondering as I'm typing this if proof by induction is a good way to go.  Edit: One major thing I forgot to add, am I correct in thinking that also, $\mathbb{E}(T) = \sum^\infty_{k=1}k\mathbb{P}(T = k)$?