Suppose I have:  srting s="C:\\someIllegalChars\\בלה.xlsx"; FileInfo fi = new FileInfo(s);   This gives:  Illegal characters in path. :::  ::: System.ArgumentException: Illegal characters in path.    at System.Security.Permissions.FileIOPermission.EmulateFileIOPermissionChecks(String fullPath)    at System.Security.Permissions.FileIOPermission.QuickDemand(FileIOPermissionAccess access, String fullPath, Boolean checkForDuplicates, Boolean needFullPath)    at System.IO.FileInfo.Init(String fileName, Boolean checkHost)    at ...   I need a function that will fix this type of Illegal  strings, something like:  string Fixer(string){ return fixed string; }
I need a robust and simple way to remove illegal path and file characters from a simple string. I've used the below code but it doesn't seem to do anything, what am I missing?  using System; using System.IO;  namespace ConsoleApplication1 {     class Program     {         static void Main(string[] args)         {             string illegal = "\"M&lt;&gt;\"\\a/ry/ h**ad:&gt;&gt; a\\/:*?\"&lt;&gt;| li*tt|le|| la\"mb.?";              illegal = illegal.Trim(Path.GetInvalidFileNameChars());             illegal = illegal.Trim(Path.GetInvalidPathChars());              Console.WriteLine(illegal);             Console.ReadLine();         }     } }
OpenVPN restriction Ive set up an OpenVPN server at my place and handed out a certificate to a client who has an openvpn client at his place.  I need require that he should be able to connect to the vpn server only from one IP address (his current one).  How can I do this? How should we handle downvote retaliation? I have a situation where I'm trying to figure out what the right thing to do is on SO.    I see a question.  I answer the question.  I see there are a couple other answers.  One answers the question well, though with less explanation than my answer.  The other answer seems both wrong and irrelevant to the question (doesn't answer the question at all).  I comment to that effect.  The "wrong" part is edited out, but the author of the answer doesn't respond to how their answer actually answers the question.  In fact, they seem offended that I don't "get" it.  After giving them several chances to explain how their answer is relevant to the question and seeing their attitude, I decide to downvote their answer as I don't see how it addresses the question at all and the author won't explain.  They retaliate and downvote my answer and admit in their comments that their downvote of my answer has nothing to do with the content of my answer and only because they don't like me disputing their answer.  Did I do the right thing by downvoting their answer?  Do I just have to live with their downvote retaliation?  Anything I should have done differently?  I also have no way of knowing this for sure, but the next question I answered was upvoted, then downvoted so perhaps this same person is stalking my answers and downvoting other answers of mine too with no comment.  As long as this doesn't continue, I'm not losing sleep over a couple downvotes, but I do wonder if I should have done anything differently.  Followup Later After I Posted This Question: After thinking about it for a little while, the person who disagreed with me decided to delete their post.  So, eventually the message did get through to them.  I don't know if they rescinded their downvote or not (or if they even could). Expected value of $|X - Y|$ Let $X \sim U(0, 1)$ and $Y \sim U(0, 2)$ be independent random variables. What's the expected value of $|X - Y|$? I found $f_{X}(x) = 1$ and $f_{Y} = \frac{1}{2}$ so that $f_{XY}(x, y) = \frac{1}{2}$ and $$\mathbb{E}[|x - y|] = \int_{0}^{1} \int_{0}^{2} \frac{|x - y|}{2} \mathop{dy} \mathop{dx},$$ but how can I compute this quantity? It looks tricky. I know the trick where you split the integral in the one-dimensional case, but I'm having trouble getting it in the two-dimensional case. I need to compute the improper integral $$ \int_{-\infty}^{\infty}\frac{x^{2}}{\cosh\left(x\right)}\,{\rm d}x $$ using contour integration and possibly principal values.  Trying to approach this as I would normally approach evaluating an improper integral using contour integration doesn't work here, and doesn't really give me any clues as to how I should do it. This normal approach is namely evaluating the contour integral $$ \oint_{C}{\frac{z^2}{\cosh\left(z\right)}\mathrm{d}z} $$ using a semicircle in the upper-half plane centered at the origin, but the semicircular part of this contour integral does not vanish since $\cosh\left(z\right)$ has period $2\pi\mathrm{i}$ and there are infinitely-many poles of the integrand along the imaginary axis given by $-\pi\mathrm{i}/2 + 2n\pi\mathrm{i}$ and $\pi\mathrm{i}/2 + 2n\pi\mathrm{i}$ for $n \in \mathbb{Z}$. The residues of the integrand at these simple poles are $-\frac{1}{4}\mathrm{i}\pi^{2}\left(1 - 4n\right)^{2}$ and $\frac{1}{4}\mathrm{i}\left(4\pi n + \pi\right)^{2}$, so that even when we add up all of the poles, we have the sum $4\pi^{2}\mathrm{i}\sum_{n = 0}^{\infty}\,n$, which clearly diverges.  Any hints would be greatly appreciated. The Unix environment has some excellent tools for parsing text in various forms. However, of late, the data is not in the traditional (historical) formats (CSV, TSV, record-based or some other delimiter-based) it used to be before. Data these days is exchanged in structured formats like XML/JSON.  I know there are some good tools like sed, awk and Perl which can chew down nearly any form of data out there. However, to work with this sort of structured data, often one has to write a complete program, and, given the little time available to extract information, one has to sit down and figure out the whole logic of what one wants to query and put it down programmatically. Sometimes this is not OK – basically because the information extracted from those files acts as inputs for further work; also because of the time it takes to search for the appropriate solution and code it up. A command line tool is needed with sufficient switches to find, query and dump data.  I'm looking for tools that take a XML/JSON or other forms of structured data and dump it into other formats like csv, etc., so that from there one could use other commands to get any information out of it.  Are there any command line utilities you know of which do this kind of a job? Are there already awk/Perl scripts available to this? Finding minimum bounding extent of given pixel value within raster? How do I root my Nexus 7? I am wanting to gain root privileges on my Google Nexus 7 tablet, running Android 4.1-4.2.1. How can I do this? Lagrangian of an effective potential If there is a system, described by an Lagrangian $\mathcal{L}$ of the form   $$\mathcal{L} = T-V = \frac{m}{2}\left(\dot{r}^2+r^2\dot{\phi}^2\right) + \frac{k}{r},\tag{1}$$   where $T$ is the kinetic energy and $V$ the potential energy, it is also possible to define the total energy $E$ of the system   $$ E = T + V =\frac{m}{2}\left(\dot{r}^2+r^2\dot{\phi}^2\right) - \frac{k}{r}.\tag{2}$$  If the angular momentum $M$ is defined by $$ M = m r^{2} \dot{\phi},\tag{3}$$ then $E$ can be written as  $$ E = \frac{m}{2}\dot{r}^2 + \underbrace{\frac{M^2}{2mr^2}-\frac{k}{r}}_{V_\textrm{eff}\left(r\right)},\tag{4}$$  where the last two terms are written as new, "effective" potential $V_\textrm{eff}\left(r\right)$.    In addition, using the definition of $M$, the Lagrangian $\mathcal{L}$ can be written as  $$ \mathcal{L} = \frac{m}{2}\dot{r}^2 + \underbrace{\frac{M^2}{2mr^2}+\frac{k}{r}}_{-V_\textrm{eff}\left(r\right)},\tag{5}$$  where the sign of $V_\textrm{eff}\left(r\right)$ has been changed, since $\mathcal{L} = T-V$. But from this argument, it appears that there are two different possible ways to construct the same effective potential. This seems to me contradictory. Where is my mistake? When I input [asdf][lisp] into the search field on , without being logged in, only one tag remains. Is it broken? I've start a new job today and I am trying to set up my machine to run through their Windows server.  I've managed to get a internet connection through the server now but now I can't run apt-get update as I get a "403 Forbidden" error.  This is for every repo under my source list, apart from translations(?).  I do have a proxy in apt.conf, if I don't have it I get a 407 Permission Denied error.  Here's my apt.conf file (I have omitted my username and password)  Acquire::http::proxy "http://username:password@192.168.0.2:8080/";   Here's my sources.list  #deb cdrom:[Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release amd64 (20130213)]/ dists/precise/main/binary-i386/  #deb cdrom:[Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release amd64 (20130213)]/ dists/precise/restricted/binary-i386/ #deb cdrom:[Ubuntu 12.04.2 LTS _Precise Pangolin_ - Release amd64 (20130213)]/ precise main restricted  # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://gb.archive.ubuntu.com/ubuntu/ precise main restricted deb-src http://gb.archive.ubuntu.com/ubuntu/ precise main restricted  ## Major bug fix updates produced after the final release of the ## distribution. deb http://gb.archive.ubuntu.com/ubuntu/ precise-updates main restricted deb-src http://gb.archive.ubuntu.com/ubuntu/ precise-updates main restricted  ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu ## team. Also, please note that software in universe WILL NOT receive any ## review or updates from the Ubuntu security team. deb http://gb.archive.ubuntu.com/ubuntu/ precise universe deb-src http://gb.archive.ubuntu.com/ubuntu/ precise universe deb http://gb.archive.ubuntu.com/ubuntu/ precise-updates universe deb-src http://gb.archive.ubuntu.com/ubuntu/ precise-updates universe  ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu  ## team, and may not be under a free licence. Please satisfy yourself as to  ## your rights to use the software. Also, please note that software in  ## multiverse WILL NOT receive any review or updates from the Ubuntu ## security team. deb http://gb.archive.ubuntu.com/ubuntu/ precise multiverse deb-src http://gb.archive.ubuntu.com/ubuntu/ precise multiverse deb http://gb.archive.ubuntu.com/ubuntu/ precise-updates multiverse deb-src http://gb.archive.ubuntu.com/ubuntu/ precise-updates multiverse  ## N.B. software from this repository may not have been tested as ## extensively as that contained in the main release, although it includes ## newer versions of some applications which may provide useful features. ## Also, please note that software in backports WILL NOT receive any review ## or updates from the Ubuntu security team. deb http://gb.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse deb-src http://gb.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse  deb http://security.ubuntu.com/ubuntu precise-security main restricted deb-src http://security.ubuntu.com/ubuntu precise-security main restricted deb http://security.ubuntu.com/ubuntu precise-security universe deb-src http://security.ubuntu.com/ubuntu precise-security universe deb http://security.ubuntu.com/ubuntu precise-security multiverse deb-src http://security.ubuntu.com/ubuntu precise-security multiverse  ## Uncomment the following two lines to add software from Canonical's ## 'partner' repository. ## This software is not part of Ubuntu, but is offered by Canonical and the ## respective vendors as a service to Ubuntu users. # deb http://archive.canonical.com/ubuntu precise partner # deb-src http://archive.canonical.com/ubuntu precise partner  ## This software is not part of Ubuntu, but is offered by third-party ## developers who want to ship their latest software. deb http://extras.ubuntu.com/ubuntu precise main deb-src http://extras.ubuntu.com/ubuntu precise main   I can sort-of fix this by changing all the http in sources.list to ftp but I still have issues with ppas What are the benefits of playing an alignment other than True Neutral? Can I replace my road bike's front wheel quick release with any quick release? I lost my road bike's quick release. Pictured are what I lost. Do I need to find a specific quick release that fits, or does one size fit all/most? Getting the location from an IP address I want to retrieve information like the city, state, and country of a visitor from their IP address, so that I can customize my web page according to their location. Is there a good and reliable way to do this in PHP? I am using JavaScript for client-side scripting, PHP for server-side scripting, and MySQL for the database. Should student or supervisor be corresponding author for publications based on student research? Papers published from an academic project (MSc or PhD) usually have two authors; the first author is the student who mainly conducted the research, and the second author is the professor who supervised the projects.  The corresponding author is the one who take the responsibility of a paper, and thus, some believe that students are not yet prepared to take this responsibility.  Ideally, who should be corresponding author for papers published by MSc or PhD projects?  I understand that it mainly depends on personal agreements and preferences, but I want to know which case is more reasonable from academic logic? Any gotchas I should be aware of?  Can I store it in a text field, or do I need to use a blob? (I'm not overly familiar with either pickle or sqlite, so I wanted to make sure I'm barking up the right tree with some of my high-level design ideas.) Executing cmd.exe commands from Java Word for people who live in the same city What are the people who live in the same city are called? Any words for that? I want to use it in the following context:      I and my ____ are happy. Why does `Position` by default return a list of lists of positions instead of a simple list of positions? How to understand "with" in the following sentence? Not every job will end up with a success.   What is the meaning of "with" here? Why not use other preposition?  Could native speakers please describe the scene of this sentence for me? Thx. Can Java's NullPointerException be changed to report on which variable was null?