Search Results

Search found 1746 results on 70 pages for 'expressions'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 26/70 | < Previous Page | 22 23 24 25 26 27 28 29 30 31 32 33  | Next Page >

  • Returning a href within a string

    - by user701254
    How can I return a href within a string, I can access the start position but not sure how to get last position : Here is what I have so far : String str = "sadf ad fas dfa http:\\www.google.com sdfa sadf as dfas"; int index = str.indexOf("http"); String href = str.substring(index , ???); What should the end index be ? Note, this is targeted at j2me & I need to minimise download footprint so I cannot use regular expressions or third party regular expressions libraries.

    Read the article

  • Fixing Robocopy for SQL Server Jobs

    - by Most Valuable Yak (Rob Volk)
    Robocopy is one of, if not the, best life-saving/greatest-thing-since-sliced-bread command line utilities ever to come from Microsoft.  If you're not using it already, what are you waiting for? Of course, being a Microsoft product, it's not exactly perfect. ;)  Specifically, it sets the ERRORLEVEL to a non-zero value even if the copy is successful.  This causes a problem in SQL Server job steps, since non-zero ERRORLEVELs report as failed. You can work around this by having your SQL job go to the next step on failure, but then you can't determine if there was a genuine error.  Plus you still see annoying red X's in your job history.  One way I've found to avoid this is to use a batch file that runs Robocopy, and I add some commands after it (in red): robocopy d:\backups \\BackupServer\BackupFolder *.bak rem suppress successful robocopy exit statuses, only report genuine errors (bitmask 16 and 8 settings)set/A errlev="%ERRORLEVEL% & 24" rem exit batch file with errorlevel so SQL job can succeed or fail appropriatelyexit/B %errlev% (The REM statements are simply comments and don't need to be included in the batch file) The SET command lets you use expressions when you use the /A switch.  So I set an environment variable "errlev" to a bitwise AND with the ERRORLEVEL value. Robocopy's exit codes use a bitmap/bitmask to specify its exit status.  The bits for 1, 2, and 4 do not indicate any kind of failure, but 8 and 16 do.  So by adding 16 + 8 to get 24, and doing a bitwise AND, I suppress any of the other bits that might be set, and allow either or both of the error bits to pass. The next step is to use the EXIT command with the /B switch to set a new ERRORLEVEL value, using the "errlev" variable.  This will now return zero (unless Robocopy had real errors) and allow your SQL job step to report success. This technique should also work for other command-line utilities.  The only issues I've found is that it requires the commands to be part of a batch file, so if you use Robocopy directly in your SQL job step you'd need to place it in a batch.  If you also have multiple Robocopy calls, you'll need to place the SET/A command ONLY after the last one.  You'd therefore lose any errors from previous calls, unless you use multiple "errlev" variables and AND them together. (I'll leave this as an exercise for the reader) The SET/A syntax also permits other kinds of expressions to be calculated.  You can get a full list by running "SET /?" on a command prompt.

    Read the article

  • Parsing SQLIO Output to Excel Charts using Regex in PowerShell

    - by Jonathan Kehayias
    Today Joe Webb ( Blog | Twitter ) blogged about The Power of Regex in Powershell, and in his post he shows how to parse the SQL Server Error Log for events of interest.  At the end of his blog post Joe asked about other places where Regular Expressions have been useful in PowerShell so I thought I’d blog my script for parsing SQLIO output using Regex in PowerShell, to populate an Excel worksheet and build charts based on the results automatically. If you’ve never used SQLIO, Brent Ozar ( Blog...(read more)

    Read the article

  • Parsing SQLIO Output to Excel Charts using Regex in PowerShell

    - by Jonathan Kehayias
    Today Joe Webb ( Blog | Twitter ) blogged about The Power of Regex in Powershell, and in his post he shows how to parse the SQL Server Error Log for events of interest. At the end of his blog post Joe asked about other places where Regular Expressions have been useful in PowerShell so I thought I’d blog my script for parsing SQLIO output using Regex in PowerShell, to populate an Excel worksheet and build charts based on the results automatically. If you’ve never used SQLIO, Brent Ozar ( Blog | Twitter...(read more)

    Read the article

  • Parallelism in .NET – Part 14, The Different Forms of Task

    - by Reed
    Before discussing Task creation and actual usage in concurrent environments, I will briefly expand upon my introduction of the Task class and provide a short explanation of the distinct forms of Task.  The Task Parallel Library includes four distinct, though related, variations on the Task class. In my introduction to the Task class, I focused on the most basic version of Task.  This version of Task, the standard Task class, is most often used with an Action delegate.  This allows you to implement for each task within the task decomposition as a single delegate. Typically, when using the new threading constructs in .NET 4 and the Task Parallel Library, we use lambda expressions to define anonymous methods.  The advantage of using a lambda expression is that it allows the Action delegate to directly use variables in the calling scope.  This eliminates the need to make separate Task classes for Action<T>, Action<T1,T2>, and all of the other Action<…> delegate types.  As an example, suppose we wanted to make a Task to handle the ”Show Splash” task from our earlier decomposition.  Even if this task required parameters, such as a message to display, we could still use an Action delegate specified via a lambda: // Store this as a local variable string messageForSplashScreen = GetSplashScreenMessage(); // Create our task Task showSplashTask = new Task( () => { // We can use variables in our outer scope, // as well as methods scoped to our class! this.DisplaySplashScreen(messageForSplashScreen); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This provides a huge amount of flexibility.  We can use this single form of task for any task which performs an operation, provided the only information we need to track is whether the task has completed successfully or not.  This leads to my first observation: Use a Task with a System.Action delegate for any task for which no result is generated. This observation leads to an obvious corollary: we also need a way to define a task which generates a result.  The Task Parallel Library provides this via the Task<TResult> class. Task<TResult> subclasses the standard Task class, providing one additional feature – the ability to return a value back to the user of the task.  This is done by switching from providing an Action delegate to providing a Func<TResult> delegate.  If we decompose our problem, and we realize we have one task where its result is required by a future operation, this can be handled via Task<TResult>.  For example, suppose we want to make a task for our “Check for Update” task, we could do: Task<bool> checkForUpdateTask = new Task<bool>( () => { return this.CheckWebsiteForUpdate(); }); Later, we would start this task, and perform some other work.  At any point in the future, we could get the value from the Task<TResult>.Result property, which will cause our thread to block until the task has finished processing: // This uses Task<bool> checkForUpdateTask generated above... // Start the task, typically on a background thread checkForUpdateTask.Start(); // Do some other work on our current thread this.DoSomeWork(); // Discover, from our background task, whether an update is available // This will block until our task completes bool updateAvailable = checkForUpdateTask.Result; This leads me to my second observation: Use a Task<TResult> with a System.Func<TResult> delegate for any task which generates a result. Task and Task<TResult> provide a much cleaner alternative to the previous Asynchronous Programming design patterns in the .NET framework.  Instead of trying to implement IAsyncResult, and providing BeginXXX() and EndXXX() methods, implementing an asynchronous programming API can be as simple as creating a method that returns a Task or Task<TResult>.  The client side of the pattern also is dramatically simplified – the client can call a method, then either choose to call task.Wait() or use task.Result when it needs to wait for the operation’s completion. While this provides a much cleaner model for future APIs, there is quite a bit of infrastructure built around the current Asynchronous Programming design patterns.  In order to provide a model to work with existing APIs, two other forms of Task exist.  There is a constructor for Task which takes an Action<Object> and a state parameter.  In addition, there is a constructor for creating a Task<TResult> which takes a Func<Object, TResult> as well as a state parameter.  When using these constructors, the state parameter is stored in the Task.AsyncState property. While these two overloads exist, and are usable directly, I strongly recommend avoiding this for new development.  The two forms of Task which take an object state parameter exist primarily for interoperability with traditional .NET Asynchronous Programming methodologies.  Using lambda expressions to capture variables from the scope of the creator is a much cleaner approach than using the untyped state parameters, since lambda expressions provide full type safety without introducing new variables.

    Read the article

  • Le C++ expressif n° 4 : une bibliothèque de fonctions lambda en à peine 30 lignes - partie 1, un article d'Eric Niebler traduit par cob59

    Dans cet article, Eric Niebler entre dans les détails de la création de grammaires, en particulier sur le rôle des transformées, qui permettent d'appliquer une action spécifique lorsque l'entrée correspond à la grammaire donnée. De cette manière, il est possible d'étendre les fonctionnalités des expressions de Boost.Proto. Cet article explique aussi comment créer sa propre bibliothèques de fonctions pour faciliter la création d'expression Le C++ expressif n° 4 : une bibliothèque de fonctions lambda en à peine 30 lignes - partie 1 Avec l'ajout des transformées, commencez-vous à voir des doma...

    Read the article

  • Autofac

    - by csharp-source.net
    A .NET IoC container written in C#. Focus on programmatic configuration with builder syntax. Zero intrusion into existing code. Create components using reflection or with lambda expressions for unlimited flexibility. Managed disposal of any IDisposable components created by the container within a defined scope.

    Read the article

  • Of C# Iterators and Performance

    - by James Michael Hare
    Some of you reading this will be wondering, "what is an iterator" and think I'm locked in the world of C++.  Nope, I'm talking C# iterators.  No, not enumerators, iterators.   So, for those of you who do not know what iterators are in C#, I will explain it in summary, and for those of you who know what iterators are but are curious of the performance impacts, I will explore that as well.   Iterators have been around for a bit now, and there are still a bunch of people who don't know what they are or what they do.  I don't know how many times at work I've had a code review on my code and have someone ask me, "what's that yield word do?"   Basically, this post came to me as I was writing some extension methods to extend IEnumerable<T> -- I'll post some of the fun ones in a later post.  Since I was filtering the resulting list down, I was using the standard C# iterator concept; but that got me wondering: what are the performance implications of using an iterator versus returning a new enumeration?   So, to begin, let's look at a couple of methods.  This is a new (albeit contrived) method called Every(...).  The goal of this method is to access and enumeration and return every nth item in the enumeration (including the first).  So Every(2) would return items 0, 2, 4, 6, etc.   Now, if you wanted to write this in the traditional way, you may come up with something like this:       public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval)     {         List<T> newList = new List<T>();         int count = 0;           foreach (var i in list)         {             if ((count++ % interval) == 0)             {                 newList.Add(i);             }         }           return newList;     }     So basically this method takes any IEnumerable<T> and returns a new IEnumerable<T> that contains every nth item.  Pretty straight forward.   The problem?  Well, Every<T>(...) will construct a list containing every nth item whether or not you care.  What happens if you were searching this result for a certain item and find that item after five tries?  You would have generated the rest of the list for nothing.   Enter iterators.  This C# construct uses the yield keyword to effectively defer evaluation of the next item until it is asked for.  This can be very handy if the evaluation itself is expensive or if there's a fair chance you'll never want to fully evaluate a list.   We see this all the time in Linq, where many expressions are chained together to do complex processing on a list.  This would be very expensive if each of these expressions evaluated their entire possible result set on call.    Let's look at the same example function, this time using an iterator:       public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval)     {         int count = 0;         foreach (var i in list)         {             if ((count++ % interval) == 0)             {                 yield return i;             }         }     }   Notice it does not create a new return value explicitly, the only evidence of a return is the "yield return" statement.  What this means is that when an item is requested from the enumeration, it will enter this method and evaluate until it either hits a yield return (in which case that item is returned) or until it exits the method or hits a yield break (in which case the iteration ends.   Behind the scenes, this is all done with a class that the CLR creates behind the scenes that keeps track of the state of the iteration, so that every time the next item is asked for, it finds that item and then updates the current position so it knows where to start at next time.   It doesn't seem like a big deal, does it?  But keep in mind the key point here: it only returns items as they are requested. Thus if there's a good chance you will only process a portion of the return list and/or if the evaluation of each item is expensive, an iterator may be of benefit.   This is especially true if you intend your methods to be chainable similar to the way Linq methods can be chained.    For example, perhaps you have a List<int> and you want to take every tenth one until you find one greater than 10.  We could write that as:       List<int> someList = new List<int>();         // fill list here         someList.Every(10).TakeWhile(i => i <= 10);     Now is the difference more apparent?  If we use the first form of Every that makes a copy of the list.  It's going to copy the entire list whether we will need those items or not, that can be costly!    With the iterator version, however, it will only take items from the list until it finds one that is > 10, at which point no further items in the list are evaluated.   So, sounds neat eh?  But what's the cost is what you're probably wondering.  So I ran some tests using the two forms of Every above on lists varying from 5 to 500,000 integers and tried various things.    Now, iteration isn't free.  If you are more likely than not to iterate the entire collection every time, iterator has some very slight overhead:   Copy vs Iterator on 100% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 5 Copy 5 5 5 Iterator 5 50 50 Copy 28 50 50 Iterator 27 500 500 Copy 227 500 500 Iterator 247 5000 5000 Copy 2266 5000 5000 Iterator 2444 50,000 50,000 Copy 24,443 50,000 50,000 Iterator 24,719 500,000 500,000 Copy 250,024 500,000 500,000 Iterator 251,521   Notice that when iterating over the entire produced list, the times for the iterator are a little better for smaller lists, then getting just a slight bit worse for larger lists.  In reality, given the number of items and iterations, the result is near negligible, but just to show that iterators come at a price.  However, it should also be noted that the form of Every that returns a copy will have a left-over collection to garbage collect.   However, if we only partially evaluate less and less through the list, the savings start to show and make it well worth the overhead.  Let's look at what happens if you stop looking after 80% of the list:   Copy vs Iterator on 80% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 4 Copy 5 5 4 Iterator 5 50 40 Copy 27 50 40 Iterator 23 500 400 Copy 215 500 400 Iterator 200 5000 4000 Copy 2099 5000 4000 Iterator 1962 50,000 40,000 Copy 22,385 50,000 40,000 Iterator 19,599 500,000 400,000 Copy 236,427 500,000 400,000 Iterator 196,010       Notice that the iterator form is now operating quite a bit faster.  But the savings really add up if you stop on average at 50% (which most searches would typically do):     Copy vs Iterator on 50% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 2 Copy 5 5 2 Iterator 4 50 25 Copy 25 50 25 Iterator 16 500 250 Copy 188 500 250 Iterator 126 5000 2500 Copy 1854 5000 2500 Iterator 1226 50,000 25,000 Copy 19,839 50,000 25,000 Iterator 12,233 500,000 250,000 Copy 208,667 500,000 250,000 Iterator 122,336   Now we see that if we only expect to go on average 50% into the results, we tend to shave off around 40% of the time.  And this is only for one level deep.  If we are using this in a chain of query expressions it only adds to the savings.   So my recommendation?  If you have a resonable expectation that someone may only want to partially consume your enumerable result, I would always tend to favor an iterator.  The cost if they iterate the whole thing does not add much at all -- and if they consume only partially, you reap some really good performance gains.   Next time I'll discuss some of my favorite extensions I've created to make development life a little easier and maintainability a little better.

    Read the article

  • Google Python Class Day 2 Part 1

    Google Python Class Day 2 Part 1 Google Python Class Day 2 Part 1: Regular Expressions. By Nick Parlante. Support materials and exercises: code.google.com From: GoogleDevelopers Views: 18 0 ratings Time: 42:00 More in Science & Technology

    Read the article

  • Visual Basic Book Excerpt: Useful Namespaces

    This chapter provides an overview of some of the most important system namespaces and gives more detailed examples that demonstrate regular expressions, XML, cryptography, reflection, threading, parallel programming, and Direct3D....Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

    Read the article

  • Stairway to XML: Level 7 - Updating Data in an XML Instance

    You need to provide the necessary keywords and define the XQuery and value expressions in your XML DML expression in order to use the modify() method to update element and attribute values in either typed or untyped XML instances in an XML column. Robert Sheldon explains how. "It really helped us isolate where we were experiencing a bottleneck"- John Q Martin, SQL Server DBA. Get started with SQL Monitor today to solve tricky performance problems - download a free trial

    Read the article

  • How would you rank these programming skills in order of learning them? [closed]

    - by mumtaz
    As a general purpose programmer, what should you learn first and what should you learn later on? Here are some skills I wonder about... SQL Regular Expressions Multi-threading / Concurrency Functional Programming Graphics The mastery of your mother programming language's syntax/semantics/featureset The mastery of your base class framework libraries Version Control System Unit Testing XML Do you know other important ones? Please specify them... On which skills should I focus first?

    Read the article

  • Prevent hotlinking of attachments

    - by reggie
    People are able to embed my forum's attachments (vbulletin). I tried to create an htaccess rule for the hotlinking, but it did not work. RewriteCond %{HTTP_REFERER} !^$ RewriteCond %{HTTP_REFERER} !^http://(www\.)?mydomain\.com.*$ [NC] RewriteRule attachmentid=\d+(\&d=\d*)?|\.([Gg][Ii][Ff]|[Jj][Pp][Gg])$ http://mydomain.com/antihotlink.jpeg [R] Is it not possible to check for numbers in regular expressions in htaccess files?

    Read the article

  • What is a good replacement for MS Frontpage?

    - by Clay Nichols
    I've been using MS Frontpage 2003 to maintain our company website for years. Looking for a replacement that can: Import/convert a MS FrontPage website and "modernize it" (clean up the HTML to make it standards compliant, etc.) Supports (or converts) the substitutions (Include Page and Text substitutions that are done when the page is published (so they become static HTML). Leverages my knowledge of FrontPage Looks like the likely contender is Web Expressions but I'm open to objective suggestions.

    Read the article

  • T-SQL User-Defined Functions: the good, the bad, and the ugly (part 2)

    - by Hugo Kornelis
    In a previous blog post , I demonstrated just how much you can hurt your performance by encapsulating expressions and computations in a user-defined function (UDF). I focused on scalar functions that didn’t include any data access. In this post, I will complete the discussion on scalar UDFs by covering the effect of data access in a scalar UDF. Note that, like the previous post, this all applies to T-SQL user-defined functions only. SQL Server also supports CLR user-defined functions (written in...(read more)

    Read the article

  • Analyzing a programming language

    - by Matt Fenwick
    In SICP, the authors state (Section 1.1) that there are three basic "mechanisms" of programming languages: primitive expressions, which represent the simplest entities the language is concerned with means of combination, by which compound elements are built from simpler ones means of abstraction, by which compound elements can be named and manipulated as units How can I analyze a mainstream programming language (Java, for example) in terms of these elements or mechanisms?

    Read the article

  • T-SQL User-Defined Functions: the good, the bad, and the ugly (part 2)

    - by Hugo Kornelis
    In a previous blog post , I demonstrated just how much you can hurt your performance by encapsulating expressions and computations in a user-defined function (UDF). I focused on scalar functions that didn’t include any data access. In this post, I will complete the discussion on scalar UDFs by covering the effect of data access in a scalar UDF. Note that, like the previous post, this all applies to T-SQL user-defined functions only. SQL Server also supports CLR user-defined functions (written in...(read more)

    Read the article

  • Lambda&rsquo;s for .NET made easy&hellip;

    - by mbcrump
    The purpose of my blog is to explain things for a beginner to intermediate c# programmer. I’ve seen several blog post that use lambda expressions always assuming the audience is familiar with them. The purpose of this post is to make them simple and easily understood. Let’s begin with a definition. A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types. So anonymous function… delegates or expression tree types? I don’t get it??? Confused yet?   Lets break this into a few definitions and jump right into the code. anonymous function – is an "inline" statement or expression that can be used wherever a delegate type is expected. delegate - is a type that references a method. Once a delegate is assigned a method, it behaves exactly like that method. The delegate method can be used like any other method, with parameters and a return value. Expression trees - represent code in a tree-like data structure, where each node is an expression, for example, a method call or a binary operation such as x < y.   Don’t worry if this still sounds confusing, lets jump right into the code with a simple 3 line program. We are going to use a Function Delegate (all you need to remember is that this delegate returns a value.) Lambda expressions are used most commonly with the Func and Action delegates, so you will see an example of both of these. Lambda Expression 3 lines. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             Func<int, int> myfunc = x => x *x;             Console.WriteLine(myfunc(6).ToString());             Console.ReadLine();         }       } } Is equivalent to Old way of doing it. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {               Console.WriteLine(myFunc(6).ToString());             Console.ReadLine();         }            static int myFunc(int x)          {              return x * x;            }       } } In the example, there is a single parameter, x, and the expression is x*x. I’m going to stop here to make sure you are still with me. A lambda expression is an unnamed method written in place of a delegate instance. In other words, the compiler converts the lambda expression to either a : A delegate instance An expression tree All lambda have the following form: (parameters) => expression or statement block Now look back to the ones we have created. It should start to sink in. Don’t get stuck on the => form, use it as an identifier of a lambda. A Lamba expression can also be written in the following form: Lambda Expression. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             Func<int, int> myFunc = x =>             {                 return x * x;             };               Console.WriteLine(myFunc(6).ToString());             Console.ReadLine();         }       } } This form may be easier to read but consumes more space. Lets try an Action delegate – this delegate does not return a value. Action Delegate example. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             Action<string> myAction = (string x) => { Console.WriteLine(x); };             myAction("michael has made this so easy");                                   Console.ReadLine();         }       } } Lambdas can also capture outer variables (such as the example below) A lambda expression can reference the local variables and parameters of the method in which it’s defined. Outer variables referenced by a lambda expression are called captured variables. Capturing Outer Variables using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             string mike = "Michael";             Action<string> myAction = (string x) => {                 Console.WriteLine("{0}{1}", mike, x);          };             myAction(" has made this so easy");                                   Console.ReadLine();         }       } } Lamba’s can also with a strongly typed list to loop through a collection.   Used w a strongly typed list. using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace ConsoleApplication7 {     class Program     {          static void Main(string[] args)         {             List<string> list = new List<string>() { "1", "2", "3", "4" };             list.ForEach(s => Console.WriteLine(s));             Console.ReadLine();         }       } } Outputs: 1 2 3 4 I think this will get you started with Lambda’s, as always consult the MSDN documentation for more information. Still confused? Hopefully you are not.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 22 23 24 25 26 27 28 29 30 31 32 33  | Next Page >