Casting string to enum I'm reading file content and take string at exact location like this   string fileContentMessage = File.ReadAllText(filename).Substring(411, 3);   Output will always be either Ok or Err  On the other side I have MyObject which have ContentEnum like this  public class MyObject      {       public enum ContentEnum { Ok = 1, Err = 2 };               public ContentEnum Content { get; set; }     }   Now, on the client side I want to use code like this (to cast my string fileContentMessage to Content property)  string fileContentMessage = File.ReadAllText(filename).Substring(411, 3);      MyObject myObj = new MyObject ()     {        Content = /// ///,     };
Convert a string to an enum in C# What's the best way to convert a string to an enumeration value in C#? I have an HTML select tag containing the values of an enumeration. When the page is posted, I want to pick up the value (which will be in the form of a string) and convert it to the corresponding enumeration value. In an ideal world, I could do something like this: StatusEnum MyStatus = StatusEnum.Parse(&quot;Active&quot;);  but that isn't a valid code.
Suppose $\sum a_n$ converges absolutely and $\sum b_n$ converges. Give an example where the Cauchy product does not converge absolutely. Problem:  Suppose $\sum_{n=0}^{\infty} a_n$ converges absolutely and $\sum_{n=0}^{\infty} b_n$ converges. Give an example where the Cauchy product, defined as $\sum_{n=0}^{\infty} c_n$ where $c_n=\sum_{k=0}^{n} a_k b_{n-k}$, does not converge absolutely.  Question:  I have been scratching my head over this for a while. What would an example be? How to get status start_date and end_date from status_track table? I have two tables:   things:  +------+----------------+------------+ | id   | current_status | created_at | +------+----------------+------------+ | 7770 | active         | 2016-08-09 | +------+----------------+------------+  thing_status_tract:  +----------+-------------+-----------+---------------------+ | thing_id | status_from | status_to | changed_at          | +----------+-------------+-----------+---------------------+ |     7770 | incomplete  | inactive  | 2016-08-09 16:26:22 | |     7770 | inactive    | active    | 2016-08-10 12:31:04 | +----------+-------------+-----------+---------------------+    I need data in the following form. This table has a status and its corresponding start and end timestamp for a particular thing_id:  +----------+-------------+---------------------+---------------------+ | thing_id | status      | status_start_date   | status_end_date     | +----------+-------------+---------------------+---------------------+ |     7770 | incomplete  | 2016-08-09 00:00:00 | 2016-08-09 16:26:22 | |     7770 | inactive    | 2016-08-09 16:26:22 | 2016-08-10 12:31:04 | |     7770 | active      | 2016-08-10 12:31:04 | now()               | +----------+-------------+---------------------+---------------------+   How to do that with a SQL query? Multiple one to many relationships in series I am making a DB for storing reports that have following fields:  Ad_system, Ad_Campaing, Ad_Group, Keyword, Date, Impressions, Clicks, Conversions   Logic is that, Ad_system can have multiple Ad_Campaings, Ad_Campaing can have multiple Ad_Groups and Ad_Groups can have multiple Keywords, and for every Keyword there is a report. Should It be like this? Because it kind of makes sense to me, but it doesn't look correct. Primary key can also be:  ad.system.name for first table  ad.system.name ad.campaing.name for second table  ad.system.name ad.campaing.name ad.group.name for third table  ad.system.name ad.campaing.name ad.group.name keyword for fourth table  They will always be unique, but then Report will always have all DB columns in it, so it's kind of redundant.  Is the approach that I have in the diagram below correct? Or is a better one what I just described? If I am not mistaken both should satisfy 3rd NF. I just read a book "Linear Algebra and Its Applications 4E" by David C. Lay. The book is (should be) LaTeX typeset. The matrix and equations are so nice, please see the following 3 examples:        It's so beautiful, so I want get the same effect inside my paper. Here is my code:   \usepackage{amsmath} \usepackage{colortbl} \newcommand\y{\cellcolor{clight2}} \definecolor{clight2}{RGB}{212, 237, 244}%  %%% \[A=\left[ \begin{array}{ccccc} \y 0 &amp; -3 &amp; -6 &amp; 4 &amp; 9 \\    -1 &amp; \y -2 &amp; -1 &amp; 3 &amp; 1 \\ -2 &amp; -3 &amp; 0 &amp; \y 3 &amp; -1 \\ 1 &amp; 4 &amp; 5 &amp; -9 &amp; -7      \end{array} \right]\]  \[A=\left[\begin{array}{cccccc} \rowcolor{clight2} 3 &amp; -9 &amp; 12 &amp; -9 &amp; 6 &amp; 15\\ 0 &amp; 2 &amp; -4 &amp; 4 &amp; 2 &amp; -6 \\ 0 &amp; 3 &amp; -6 &amp; 6 &amp; 4 &amp; -5 \end{array} \right]\]   And the result:     But how to add these arrows?? Why is mathematical induction a valid proof technique? i keep getting the script error problem every time i try using polygon to raster tool in ArcGIS 10.1. Please help me how I can solve this?  screenshot embedded I was just wondering how can you use "there is" followed by a word that is in plural, e.g  "There's cupcakes in the fridge"  and  "There is a couple of things we can do --"   Is it just slang? 70s TV miniseries: antagonist gets followers to his pacifist ideology through mind control devices I am trying to recall the name of TV-series that was aired in the 70s (possibly only in selected European countries?). IIRC it was a French production. The bad guy was using some kind of mind control devices. He was gradually getting more and more people as followers to his pacifist ideology (it was the cold war era, and pacifism might have struck a chord even without mind control).  His modus operandi was to send a dozen or so (mind-controlled) cronies to surround a new victim. They would form a square around the helpless target, forcing him to walk into a building, where mind control devices were surgically installed.  The protagonists were trying to organize a resistance movement. IIRC they failed, as the bad guy had good intelligence about their plans. Why are polymorphic values not inferred in Haskell? By $A\oplus B$ we denote the symmectric difference of two sets. The definition is $A\oplus B =(A\setminus B) \cup (B\setminus A)$. Now I hope to show that $A\oplus (B\oplus C) = (A\oplus B)\oplus C$. I remember that there's an elegant proof, but I forget its detail. (The first step is to show $A\oplus (A\oplus B) = B$, and maybe applying this formula, we can obtain associativity.) Book ID: Astronauts and Lab Students can create portals through space 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! Is there an English phrase for an inability to actually *leave* already? There is a Hungarian expression, küszöbgörcs, which literally means "threshold-cramp", and is used to describe that long conversation you have in the entryway, with all the guests awkwardly holding their coats and purses, and every so often somebody says something like "Ok, we really have to leave now, but just one more thing...", and then the conversation is good for another half an hour at least.  I've searched in vain for an equivalent idiom in English, yet I feel sure it must exist: I know English speakers are equally susceptible to this malady, it's not a uniquely Hungarian thing. I will sometimes use literal translations, like the aforementioned threshold-cramp (or doorway-spasm), but then I need to explain it, and that's less than satisfactory. (Plus it leads to more threshold cramping.) Lagrange Multipler KKT condition I am looking at SVM, and reviewing Lagrange multiplier. Let's say with the constraint function $$g(x,y) = x^2 + y^2 -1 &gt; 0, $$ I am maximizing $$f(x,y) = x + y -1 .$$ Intuitively, since the constraint function does not provide a finite constrained region, there is no solution, and $f(x,y)$ can infinitely increase.  However, if I just plainly proceed with Lagrange multiplier calculation,  $$L(x,\lambda) = (x + y -1) +\lambda(x^2 + y^2 -1)$$ I get the solution: $$y,x = -\sqrt{2}/2, \lambda = 1/\sqrt{2}$$ And this still satisfies KKT conditions although the solution is wrong.  $$g(x) =&gt; 0 , \lambda =&gt;      0, \lambda g(x) = 0.$$  I expected that I would have some result that conflicted KKT conditions, but nothing was violated.   Does this mean that Lagrange multiplier under KKT conditions can produce a solution that cannot be solved, without giving any indication of intractability?  If functions are complicated, what's the systematic way to confirm that the optimization with inequality constraint functions is solvable using Lagrange multiplier? Prove: $\binom{n}{0}F_0+\binom{n}{1}F_1+\binom{n}{2}F_2+\cdots+\binom{n}{n}F_n=F_{2n}$;  I was stuck with this question for a while... Help me please!!! Thanks!!! g++ undefined reference to typeinfo How can I get distribution name and version number in a simple shell script? I'm working on a simple bash script that should be able to run on Ubuntu and CentOS distributions (support for Debian and Fedora/RHEL would be a plus) and I need to know the name and version of the distribution the script is running (in order to trigger specific actions, for instance the creation of repositories). So far what I've got is this:  OS=$(awk '/DISTRIB_ID=/' /etc/*-release | sed 's/DISTRIB_ID=//' | tr '[:upper:]' '[:lower:]') ARCH=$(uname -m | sed 's/x86_//;s/i[3-6]86/32/') VERSION=$(awk '/DISTRIB_RELEASE=/' /etc/*-release | sed 's/DISTRIB_RELEASE=//' | sed 's/[.]0/./')  if [ -z "$OS" ]; then     OS=$(awk '{print $1}' /etc/*-release | tr '[:upper:]' '[:lower:]') fi  if [ -z "$VERSION" ]; then     VERSION=$(awk '{print $3}' /etc/*-release) fi  echo $OS echo $ARCH echo $VERSION   This seems to work, returning ubuntu or centos (I haven't tried others) as the release name. However, I have a feeling that there must be an easier, more reliable way of finding this out -- is that true?  It doesn't work for RedHat. /etc/redhat-release contains : Redhat Linux Entreprise release 5.5  So, the version is not the third word, you'd better use :  OS_MAJOR_VERSION=`sed -rn 's/.*([0-9])\.[0-9].*/\1/p' /etc/redhat-release` OS_MINOR_VERSION=`sed -rn 's/.*[0-9].([0-9]).*/\1/p' /etc/redhat-release` echo "RedHat/CentOS $OS_MAJOR_VERSION.$OS_MINOR_VERSION" Can I install Android on my non-Android device? Maybe the underlying question is what the Voltage-Current curve looks like. Can I drive it from a voltage source (like you drive a heater) or from a current source (like you drive an LED)? Or even different than those two options?  ADDITIONAL1: Say (hypothetically) I have two commercially available identical Peltier's, they are spec'd 6V/3A. Can I connect these in series to a 12Vdc power supply without any worries?  CONCLUSION1: Current/Voltage load curve is reasonably linear, both driving from current or voltage source will do fine as long as the device is operated within its spec. (Olin Lathrop, Russell McMahon)  CONCLUSION2: Don't drive a Peltier from PWM, power loss due to current increase, grows more rapidly than cooling power. (Olin Lathrop)  CONCLUSION3: Beware the mechanical wear of the device with continues cycling. Eg. don't use a thermostat on/off controller. (Russell McMahon) Is it possible to show a screensaver on a secondary monitor while using the primary monitor? I have an iMac with a large format display set up as a secondary monitor that we use as a television for watching movies.  When I am just using the iMac, I would like for the secondary display to display something interesting rather than just the wallpaper.  Is it possible to set up a screensaver that appears on the second monitor (I really like the iPhoto slideshow) while allowing me to use the primary iMac monitor?  I would even be happy if it wasn't technically a screen saver, but just any sort of slideshow that could be displayed on one monitor while I work on the other.  Currently if I play a slideshow in iPhoto, the other monitor goes blank. :(