Search Results

Search found 10235 results on 410 pages for 'inner loop'.

Page 87/410 | < Previous Page | 83 84 85 86 87 88 89 90 91 92 93 94  | Next Page >

  • Which is faster join

    - by Costa
    Hi Which is faster SELECT * FROM X INNER JOIN Y ON x.Record_ID = y.ForignKey_NotIndexed_NotUnique or SELECT * FROM X INNER JOIN Y ON y.ForignKey_NotIndexed_NotUnique = x.Record_ID

    Read the article

  • C#: Does an IDisposable in a Halted Iterator Dispose?

    - by James Michael Hare
    If that sounds confusing, let me give you an example. Let's say you expose a method to read a database of products, and instead of returning a List<Product> you return an IEnumerable<Product> in iterator form (yield return). This accomplishes several good things: The IDataReader is not passed out of the Data Access Layer which prevents abstraction leak and resource leak potentials. You don't need to construct a full List<Product> in memory (which could be very big) if you just want to forward iterate once. If you only want to consume up to a certain point in the list, you won't incur the database cost of looking up the other items. This could give us an example like: 1: // a sample data access object class to do standard CRUD operations. 2: public class ProductDao 3: { 4: private DbProviderFactory _factory = SqlClientFactory.Instance 5:  6: // a method that would retrieve all available products 7: public IEnumerable<Product> GetAvailableProducts() 8: { 9: // must create the connection 10: using (var con = _factory.CreateConnection()) 11: { 12: con.ConnectionString = _productsConnectionString; 13: con.Open(); 14:  15: // create the command 16: using (var cmd = _factory.CreateCommand()) 17: { 18: cmd.Connection = con; 19: cmd.CommandText = _getAllProductsStoredProc; 20: cmd.CommandType = CommandType.StoredProcedure; 21:  22: // get a reader and pass back all results 23: using (var reader = cmd.ExecuteReader()) 24: { 25: while(reader.Read()) 26: { 27: yield return new Product 28: { 29: Name = reader["product_name"].ToString(), 30: ... 31: }; 32: } 33: } 34: } 35: } 36: } 37: } The database details themselves are irrelevant. I will say, though, that I'm a big fan of using the System.Data.Common classes instead of your provider specific counterparts directly (SqlCommand, OracleCommand, etc). This lets you mock your data sources easily in unit testing and also allows you to swap out your provider in one line of code. In fact, one of the shared components I'm most proud of implementing was our group's DatabaseUtility library that simplifies all the database access above into one line of code in a thread-safe and provider-neutral way. I went with my own flavor instead of the EL due to the fact I didn't want to force internal company consumers to use the EL if they didn't want to, and it made it easy to allow them to mock their database for unit testing by providing a MockCommand, MockConnection, etc that followed the System.Data.Common model. One of these days I'll blog on that if anyone's interested. Regardless, you often have situations like the above where you are consuming and iterating through a resource that must be closed once you are finished iterating. For the reasons stated above, I didn't want to return IDataReader (that would force them to remember to Dispose it), and I didn't want to return List<Product> (that would force them to hold all products in memory) -- but the first time I wrote this, I was worried. What if you never consume the last item and exit the loop? Are the reader, command, and connection all disposed correctly? Of course, I was 99.999999% sure the creators of C# had already thought of this and taken care of it, but inspection in Reflector was difficult due to the nature of the state machines yield return generates, so I decided to try a quick example program to verify whether or not Dispose() will be called when an iterator is broken from outside the iterator itself -- i.e. before the iterator reports there are no more items. So I wrote a quick Sequencer class with a Dispose() method and an iterator for it. Yes, it is COMPLETELY contrived: 1: // A disposable sequence of int -- yes this is completely contrived... 2: internal class Sequencer : IDisposable 3: { 4: private int _i = 0; 5: private readonly object _mutex = new object(); 6:  7: // Constructs an int sequence. 8: public Sequencer(int start) 9: { 10: _i = start; 11: } 12:  13: // Gets the next integer 14: public int GetNext() 15: { 16: lock (_mutex) 17: { 18: return _i++; 19: } 20: } 21:  22: // Dispose the sequence of integers. 23: public void Dispose() 24: { 25: // force output immediately (flush the buffer) 26: Console.WriteLine("Disposed with last sequence number of {0}!", _i); 27: Console.Out.Flush(); 28: } 29: } And then I created a generator (infinite-loop iterator) that did the using block for auto-Disposal: 1: // simply defines an extension method off of an int to start a sequence 2: public static class SequencerExtensions 3: { 4: // generates an infinite sequence starting at the specified number 5: public static IEnumerable<int> GetSequence(this int starter) 6: { 7: // note the using here, will call Dispose() when block terminated. 8: using (var seq = new Sequencer(starter)) 9: { 10: // infinite loop on this generator, means must be bounded by caller! 11: while(true) 12: { 13: yield return seq.GetNext(); 14: } 15: } 16: } 17: } This is really the same conundrum as the database problem originally posed. Here we are using iteration (yield return) over a large collection (infinite sequence of integers). If we cut the sequence short by breaking iteration, will that using block exit and hence, Dispose be called? Well, let's see: 1: // The test program class 2: public class IteratorTest 3: { 4: // The main test method. 5: public static void Main() 6: { 7: Console.WriteLine("Going to consume 10 of infinite items"); 8: Console.Out.Flush(); 9:  10: foreach(var i in 0.GetSequence()) 11: { 12: // could use TakeWhile, but wanted to output right at break... 13: if(i >= 10) 14: { 15: Console.WriteLine("Breaking now!"); 16: Console.Out.Flush(); 17: break; 18: } 19:  20: Console.WriteLine(i); 21: Console.Out.Flush(); 22: } 23:  24: Console.WriteLine("Done with loop."); 25: Console.Out.Flush(); 26: } 27: } So, what do we see? Do we see the "Disposed" message from our dispose, or did the Dispose get skipped because from an "eyeball" perspective we should be locked in that infinite generator loop? Here's the results: 1: Going to consume 10 of infinite items 2: 0 3: 1 4: 2 5: 3 6: 4 7: 5 8: 6 9: 7 10: 8 11: 9 12: Breaking now! 13: Disposed with last sequence number of 11! 14: Done with loop. Yes indeed, when we break the loop, the state machine that C# generates for yield iterate exits the iteration through the using blocks and auto-disposes the IDisposable correctly. I must admit, though, the first time I wrote one, I began to wonder and that led to this test. If you've never seen iterators before (I wrote a previous entry here) the infinite loop may throw you, but you have to keep in mind it is not a linear piece of code, that every time you hit a "yield return" it cedes control back to the state machine generated for the iterator. And this state machine, I'm happy to say, is smart enough to clean up the using blocks correctly. I suspected those wily guys and gals at Microsoft engineered it well, and I wasn't disappointed. But, I've been bitten by assumptions before, so it's good to test and see. Yes, maybe you knew it would or figured it would, but isn't it nice to know? And as those campy 80s G.I. Joe cartoon public service reminders always taught us, "Knowing is half the battle...". Technorati Tags: C#,.NET

    Read the article

  • What is Deep Linking and How is it Useful For My Website?

    People talking about deep linking, well I don't honestly see it a lot, but it's definitely very powerful, when you can understand how/why it works and how you can create deep backlinks, you'll be able to understand how to improve the traffic you get from Google, but ranking for more keywords. Deep link is more or less building backlinks to inner pages of your website, for example instead of just building backlinks for your index/domain, you should really build backlinks to your inner pages as well.

    Read the article

  • SQL SERVER – SSIS Parameters in Parent-Child ETL Architectures – Notes from the Field #040

    - by Pinal Dave
    [Notes from Pinal]: SSIS is very well explored subject, however, there are so many interesting elements when we read, we learn something new. A similar concept has been Parent-Child ETL architecture’s relationship in SSIS. Linchpin People are database coaches and wellness experts for a data driven world. In this 40th episode of the Notes from the Fields series database expert Tim Mitchell (partner at Linchpin People) shares very interesting conversation related to how to understand SSIS Parameters in Parent-Child ETL Architectures. In this brief Notes from the Field post, I will review the use of SSIS parameters in parent-child ETL architectures. A very common design pattern used in SQL Server Integration Services is one I call the parent-child pattern.  Simply put, this is a pattern in which packages are executed by other packages.  An ETL infrastructure built using small, single-purpose packages is very often easier to develop, debug, and troubleshoot than large, monolithic packages.  For a more in-depth look at parent-child architectures, check out my earlier blog post on this topic. When using the parent-child design pattern, you will frequently need to pass values from the calling (parent) package to the called (child) package.  In older versions of SSIS, this process was possible but not necessarily simple.  When using SSIS 2005 or 2008, or even when using SSIS 2012 or 2014 in package deployment mode, you would have to create package configurations to pass values from parent to child packages.  Package configurations, while effective, were not the easiest tool to work with.  Fortunately, starting with SSIS in SQL Server 2012, you can now use package parameters for this purpose. In the example I will use for this demonstration, I’ll create two packages: one intended for use as a child package, and the other configured to execute said child package.  In the parent package I’m going to build a for each loop container in SSIS, and use package parameters to pass in a value – specifically, a ClientID – for each iteration of the loop.  The child package will be executed from within the for each loop, and will create one output file for each client, with the source query and filename dependent on the ClientID received from the parent package. Configuring the Child and Parent Packages When you create a new package, you’ll see the Parameters tab at the package level.  Clicking over to that tab allows you to add, edit, or delete package parameters. As shown above, the sample package has two parameters.  Note that I’ve set the name, data type, and default value for each of these.  Also note the column entitled Required: this allows me to specify whether the parameter value is optional (the default behavior) or required for package execution.  In this example, I have one parameter that is required, and the other is not. Let’s shift over to the parent package briefly, and demonstrate how to supply values to these parameters in the child package.  Using the execute package task, you can easily map variable values in the parent package to parameters in the child package. The execute package task in the parent package, shown above, has the variable vThisClient from the parent package mapped to the pClientID parameter shown earlier in the child package.  Note that there is no value mapped to the child package parameter named pOutputFolder.  Since this parameter has the Required property set to False, we don’t have to specify a value for it, which will cause that parameter to use the default value we supplied when designing the child pacakge. The last step in the parent package is to create the for each loop container I mentioned earlier, and place the execute package task inside it.  I’m using an object variable to store the distinct client ID values, and I use that as the iterator for the loop (I describe how to do this more in depth here).  For each iteration of the loop, a different client ID value will be passed into the child package parameter. The final step is to configure the child package to actually do something meaningful with the parameter values passed into it.  In this case, I’ve modified the OleDB source query to use the pClientID value in the WHERE clause of the query to restrict results for each iteration to a single client’s data.  Additionally, I’ll use both the pClientID and pOutputFolder parameters to dynamically build the output filename. As shown, the pClientID is used in the WHERE clause, so we only get the current client’s invoices for each iteration of the loop. For the flat file connection, I’m setting the Connection String property using an expression that engages both of the parameters for this package, as shown above. Parting Thoughts There are many uses for package parameters beyond a simple parent-child design pattern.  For example, you can create standalone packages (those not intended to be used as a child package) and still use parameters.  Parameter values may be supplied to a package directly at runtime by a SQL Server Agent job, through the command line (via dtexec.exe), or through T-SQL. Also, you can also have project parameters as well as package parameters.  Project parameters work in much the same way as package parameters, but the parameters apply to all packages in a project, not just a single package. Conclusion Of the numerous advantages of using catalog deployment model in SSIS 2012 and beyond, package parameters are near the top of the list.  Parameters allow you to easily share values from parent to child packages, enabling more dynamic behavior and better code encapsulation. If you want me to take a look at your server and its settings, or if your server is facing any issue we can Fix Your SQL Server. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: Notes from the Field, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

    Read the article

  • Implementing Brainf*ck loops in an interpreter

    - by sub
    I want to build a Brainf*ck (Damn that name) interpreter in my freshly created programming language to prove it's turing-completeness. Now, everything is clear so far (<+-,.) - except one thing: The loops ([]). I assume that you know the (extremely hard) BF syntax from here on: How do I implement the BF loops in my interpreter? How could the pseudocode look like? What should I do when the interpreter reaches a loop beginning ([) or a loop end (])? Checking if the loop should continue or stop is not the problem (current cell==0), but: When and where do I have to check? How to know where the loop beginning is located? How to handle nested loops? As loops can be nested I suppose that I can't just use a variable containing the starting position of the current loop. I've seen very small BF interpreters implemented in various languages, I wonder how they managed to get the loops working but can't figure it out.

    Read the article

  • How can I pause a BackgroundWorker? Or something similar...

    - by juan
    I was using a BackgroundWorker to download some web sites by calling WebClient.DownloadString inside a loop. I wanted the option for the user to cancel in the middle of downloading stuff, so I called CancelAsync whenever I found that CancellationPending was on in the middle of the loop. But now I noticed that the function DownloadString kinda freezes sometimes, so I decided to use DownloadStringAsync instead (all this inside the other thread created with BackgroundWorker). An since and don't want to rewrite my whole code by having to exit the loop and the function after calling DownloadStringAsync, I made a while loop right after calling it that does nothing but checks for a variable bool Stop that I turn true either when the DownloadStringCompleted event handler is called or when the user request to cancel the operation. Now, the weird thing is that it works fine on the debug version, but on the release one, the program freezes in the while loop like if it were the main thread.

    Read the article

  • Exalogic 2.0.1 Tea Break Snippets - Modifying the Default Shipped Template

    - by The Old Toxophilist
    Having installed your Exalogic Virtual environment by default you have a single template which can be used to create your vServers. Although this template is suitable for creating simple test or development vServers it is recommended that you look at creating your own custom vServers that match the environment you wish to build and deploy. Therefore this Tea Time Snippet will take you through the simple process of modifying the standard template. Before You Start To edit the template you will need the Oracle ModifyJeos Utility which can be downloaded from the eDelivery Site. Once the ModifyJeos Utility has been downloaded we can install the rpms onto either an existing vServer or one of the Control vServers. rpm -ivh ovm-modify-jeos-1.0.1-10.el5.noarch.rpm rpm -ivh ovm-template-config-1.0.1-5.el5.noarch.rpm Alternatively you can install the modify jeos packages on a none Exalogic OEL installation or a VirtualBox image. If you are doing this, assuming OEL 5u8, you will need the following rpms. rpm -ivh ovm-modify-jeos-1.0.1-10.el5.noarch.rpm rpm -ivh ovm-el5u2-xvm-jeos-1.0.1-5.el5.i386.rpm rpm -ivh ovm-template-config-1.0.1-5.el5.noarch.rpm Base Template If you have installed the modify onto a vServer running on the Exalogic then simply mount the /export/common/images from the ZFS storage and you will be able to find the el_x2-2_base_linux_guest_vm_template_2.0.1.1.0_64.tgz (or similar depending which version you have) template file. Alternatively the latest can be downloaded from the eDelivery Site. Now we have the Template tgz we will need the extract it as follows: tar -zxvf  el_x2-2_base_linux_guest_vm_template_2.0.1.1.0_64.tgz This will create a directory called BASE which will contain the System.img (VServer image) and vm.cfg (VServer Config information). This directory should be renamed to something more meaning full that indicates what we have done to the template and then the Simple name / name in the vm.cfg editted for the same reason. Modifying the Template Resizing Root File System By default the shipped template has a root size of 4 GB which will leave a vServer created from it running at 90% full on the root disk. We can simply resize the template by executing the following: modifyjeos -f System.img -T <New Size MB>) For example to imcrease the default 4 GB to 40 GB we would execute: modifyjeos -f System.img -T 40960) Resizing Swap We can modify the size of the swap space within a template by executing the following: modifyjeos -f System.img -S <New Size MB>) For example to increase the swap from the default 512 MB to 4 GB we would execute: modifyjeos -f System.img -S 4096) Changing RPMs Adding RPMs To add RPMs using modifyjeos, complete the following steps: Add the names of the new RPMs in a list file, such as addrpms.lst. In this file, you should list each new RPM in a separate line. Ensure that all of the new RPMs are in a single directory, such as rpms. Run the following command to add the new RPMs: modifyjeos -f System.img -a <path_to_addrpms.lst> -m <path_to_rpms> -nogpg Where <path_to_addrpms.lst> is the path to the location of the addrpms.lst file, and <path_to_rpms> is the path to the directory that contains the RPMs. The -nogpg option eliminates signature check on the RPMs. Removing RPMs To remove RPM s using modifyjeos, complete the following steps: Add the names of the RPMs (the ones you want to remove) in a list file, such as removerpms.lst. In this file, you should list each RPM in a separate line. The Oracle Exalogic Elastic Cloud Administrator's Guide provides a list of all RPMs that must not be removed from the vServer. Run the following command to remove the RPMs: modifyjeos -f System.img -e <path_to_removerpms.lst> Where <path_to_removerpms.lst> is the path to the location of the removerpms.lst file. Mounting the System.img For all other modifications that are not supported by the modifyjeos command (adding you custom yum repositories, pre configuring NTP, modify default NFSv4 Nobody functionality, etc) we can mount the System.img and access it directly. To facititate quick and easy mounting/unmounting of the System.img I have put together the simple scripts below. MountSystemImg.sh #!/bin/sh # The script assumes it's being run from the directory containing the System.img # Export for later i.e. during unmount export LOOP=`losetup -f` export SYSTEMIMG=/mnt/elsystem # Make Temp Mount Directory mkdir -p $SYSTEMIMG # Create Loop for the System Image losetup $LOOP System.img kpartx -a $LOOP mount /dev/mapper/`basename $LOOP`p2 $SYSTEMIMG #Change Dir into mounted Image cd $SYSTEMIMG UnmountSystemImg.sh #!/bin/sh # The script assumes it's being run from the directory containing the System.img # Assume the $LOOP & $SYSTEMIMG exist from a previous run on the MountSystemImg.sh umount $SYSTEMIMG kpartx -d $LOOP losetup -d $LOOP Packaging the Template Once you have finished modifying the template it can be simply repackaged and then imported into EMOC as described in "Exalogic 2.0.1 Tea Break Snippets - Importing Public Server Template". To do this we will simply cd to the directory above that containing the modified files and execute the following: tar -zcvf <New Template Directory> <New Template Name>.tgz The resulting.tgz file can be copied to the images directory on the ZFS and uploadd using the IB network. This entry was originally posted on the The Old Toxophilist Site.

    Read the article

  • Implement loops for python 3

    - by Alex
    Implement this loop: total up the product of the numbers from 1 to x. Implement this loop: total up the product of the numbers from a to b. Implement this loop: total up the sum of the numbers from a to b. Implement this loop: total up the sum of the numbers from 1 to x. Implement this loop: count the number of characters in a string s. i'm very lost on implementing loops these are just some examples that i am having trouble with-- if someone could help me understand how to do them that would be awesome

    Read the article

  • MS SQL Server Job with precise timing

    - by TcKs
    Hi, I have a DB with game data (map, players, etc...) and I have a game core mechanics writen in T-SQL stored procedure. I need process game loop (via the stored procedure) every "X" seconds. I tried used the SQL Job, but when I set the interval to seconds, the SQL server stops responding. If I set the interval greater than one minute, all was ok. I need game loop precise in time, e.g. the game loop will run only once and will be executed every "X" precisely (tolerance should be less than one second). Can I do it with MS SQL Server capabilities? Or should I create a windows service which will repeatly execute game loop procedure? Or should I go another way? Thanks! EDIT: The game loop stored procedure takes less than the interval.

    Read the article

  • breaking the look in jython

    - by kdev
    Hi everyone , I have a written a loop for and if condition and i want to break to loop completely when if gets satisfied. while count: i=0 for line in read_record: #print str.strip(count[1:28]) #print str.strip(read_record[i]) if string.find(str.strip(read_record[i]),str.strip(count[1:28]))>0: code=str.strip(read_record[i+19])+str.strip(read_record[i+20]) print code[25:] break i=i+1 so here if the if string.find condition gets satified i want to go to while loop flow. Please tell me what will be the best place to break and how should i modify the program so that once the if condition is satified iam out of the loop and start again with while loop .

    Read the article

  • WebSeal and jsp content updated by Ajax

    - by lior chaga
    Hey, I have a problem running an application on environment with WebSeal. It is a web application with Java server that contains many parts that are replcaed within the page according to user input. For instance - a form called Outer.jsp may contain a form:options combo-box (by spring-forms), that uppon selection of an option, a certain Div is updated with a content produced by a jsp and fetched by an Ajax call (the ajax impementation in the client is done by Prototype JavaScript framework 1.5.1.2). Let's call the content fetched by ajax - Inner.jsp So Outer.jsp is fetching Inner.jsp, which in turn uses js functions in files included by the Outer.jsp. This, I think, is where my problem starts - Inner.jsp is not familiar with any of the functions included in Outer.jsp. And so, almost any operation performed by Inner.jsp is failing miserably. Needless to say - this works perfect when running on environment without WebSeal. Note that the scripting is enabled in WebSeal junction (with the -J option). I also see that the content returned by the Ajax call includes a document.cookie added by WebSeal (not sure it matters to this problem) Can anyone assist? Thanks! Lior

    Read the article

  • Setting WPF RichTextBox width and height according to the size of a monospace font

    - by oxeb
    I am trying to fit a WPF RichTextBox to exactly accommodate a grid of characters in a particular monospace font. I am currently using FormattedText to determine the width and height of my RichTextBox, but the measurements it is providing me with are too small--specifically two characters in width too small. Is there a better way to perform this task? This does not seem to be an appropriate way to determine the size of my control. RichTextBox rtb; rtb = new RichTextBox(); FontFamily fontFamily = new FontFamily("Consolas"); double fontSize = 16; char standardizationCharacter = 'X'; String standardizationLine = ""; for(long loop = 0; loop < columns; loop ++) { standardizationLine += standardizationCharacter; } standardizationLine += Environment.NewLine; String standardizationString = ""; for(long loop = 0; loop < rows; loop ++) { standardizationString += standardizationLine; } Typeface typeface = new Typeface(fontFamily, FontStyles.Normal, FontWeights.Normal, FontStretches.Normal); FormattedText formattedText = new FormattedText(standardizationString, CultureInfo.CurrentCulture, FlowDirection.LeftToRight, typeface, fontSize, Brushes.Black); rtb.Width = formattedText.Width; rtb.Height = formattedText.Height;

    Read the article

  • Variable Assignment and loops (Java)

    - by Raven Dreamer
    Greetings Stack Overflowers, A while back, I was working on a program that hashed values into a hashtable (I don't remember the specifics, and the specifics themselves are irrelevant to the question at hand). Anyway, I had the following code as part of a "recordInput" method. tempElement = new hashElement(someInt); while(in.hasNext() == true) { int firstVal = in.nextInt(); if (firstVal == -911) { break; } tempElement.setKeyValue(firstVal, 0); for(int i = 1; i<numKeyValues;i++) { tempElement.setKeyValue(in.nextInt(), i); } elementArray[placeValue] = tempElement; placeValue++; } // close while loop } // close method This part of the code was giving me a very nasty bug -- no matter how I finagled it, no matter what input I gave the program, it would always produce an array full of only a single value -- the last one. The problem, as I later determined it, was that because I had not created the tempElement variable within the loop, and because values were not being assigned to elementArray[] until after the loop had ended -- every term was defined rather as "tempElement" -- when the loop terminated, every slot in the array was filled with the last value tempElement had taken. I was able to fix this bug by moving the declaration of tempElement within the while loop. My question to you, Stackoverflow, is whether there is another (read: better) way to avoid this bug while keeping the variable declaration of tempElement outside the while loop. (suggestions for better title and tags also appreciated)

    Read the article

  • Why doesn't gcc remove this check of a non-volatile variable?

    - by Thomas
    This question is mostly academic. I ask out of curiosity, not because this poses an actual problem for me. Consider the following incorrect C program. #include <signal.h> #include <stdio.h> static int running = 1; void handler(int u) { running = 0; } int main() { signal(SIGTERM, handler); while (running) ; printf("Bye!\n"); return 0; } This program is incorrect because the handler interrupts the program flow, so running can be modified at any time and should therefore be declared volatile. But let's say the programmer forgot that. gcc 4.3.3, with the -O3 flag, compiles the loop body (after one initial check of the running flag) down to the infinite loop .L7: jmp .L7 which was to be expected. Now we put something trivial inside the while loop, like: while (running) putchar('.'); And suddenly, gcc does not optimize the loop condition anymore! The loop body's assembly now looks like this (again at -O3): .L7: movq stdout(%rip), %rsi movl $46, %edi call _IO_putc movl running(%rip), %eax testl %eax, %eax jne .L7 We see that running is re-loaded from memory each time through the loop; it is not even cached in a register. Apparently gcc now thinks that the value of running could have changed. So why does gcc suddenly decide that it needs to re-check the value of running in this case?

    Read the article

  • PHP, MySQL prepared statements - can you use results of execute more than once by calling data_seek(

    - by Carvell Fenton
    Hello, I have a case where I want to use the results of a prepared statement more than once in a nested loop. The outer loop processes the results of another query, and the inner loop is the results of the prepared statement query. So the code would be something like this (just "pseudoish" to demonstrate the concept): // not showing the outer query, it is just a basic SELECT, not prepared statement // we'll call it $outer_query $obj_array = array(); // going to save objects in this $ids = array(18,19,20); // just example id numbers $query = "SELECT field1, field2 FROM table1 WHERE id=?"; $stmt = $db->prepare($query); foreach ($ids as $id) { $stmt->bind_param("i", $id); $stmt->execute(); $stmt->bind_result($var1, $var2); $stmt->store_result(); // I think I need this for data_seek while ($q1 = $outer_query->fetch_object()) { while ($stmt->fetch()) { if ($q1->field1 == $var1) { // looking for a match $obj = new stdClass(); $obj->var1 = $var1; $obj->var2 = $var2; $obj_array[] = $obj; $stmt->data_seek(0); // reset for outer loop break; // found match, so leave inner } } } } The problem I seem to be experiencing is that the values are not getting bound in the variables as I would expect after the first time I use fetch in the inner loop. Specifically, in one example I ran with 3 ids for the foreach, the first id was processed correctly, the second was processed incorrectly (matches were not found in the inner loop even though they existed), and then the third was processed correctly. Is there something wrong with the prepared statment function calls in the sequence I am doing above, or is this an invalid way to use the results of the prepared statement? Thanks.

    Read the article

  • Do applescript repeat loops reflect changes instantly?

    - by user1159454
    I'm making a script to open multiple folders in a directory, and it's not working as planned. I've tried outlining it and walking through the steps one by one pretending I'm the computer executing it but when I run it the outcome is very different. It uses repeat and repeat with a lot. The repeat repeats for as long as there is ANYTHING in a certain array (I mean List) and the repeat with is INSIDE of the first repeat, which repeats it's own loop with everything in the array at that time. Now, one of the actions of the repeat with loop is to change the array. Which I think would change the loop would it not? Example (foldList is A, B, C) repeat until {} repeat with folder_name in foldList do something set foldList to 1, 2, 3 end repeat end repeat What I would THINK that does is iterate through the first loop as "A", but before hitting the end it would change foldList to 1, 2, 3. So instead of going through the next loop as "B" I'd think it would go as "1" instead. But if it did that then I don't think my manual walkthrough would be off by so much. So I'm under the assumption that in Applescript when you're in a repeat with, regardless of changing the List you WILL end that loop on the last item of the first List (before the list was replaced.) Is this right?

    Read the article

  • visual studio 2008 (VB)

    - by Ousman
    hello guys, Am writing a programming with visual basic 2008 and i want the programme to be able to read and loop through a text file line by line and showing the event of the loop on a textbox or label until a button is press and the loop will stop on any number that happend to be at the loop event and when a button is press again the loop will continue from where it starts. this is my codes below and having problem with it and any help will be really great. tanks ==========================my codes======================= Imports System.IO '========================================================================================== Public Class Form1 '====================================================================================== 'Dim nFileNum As Integer = FreeFile() ' Get a free file number Dim strFileName As String = "C:\scb.txt" Dim objFilename As FileStream = New FileStream(strFileName, FileMode.Open, FileAccess.Read, FileShare.Read) Dim objFileRead As StreamReader = New StreamReader(objFilename) 'Dim lLineCount As Long 'Dim sNextLine As String '====================================================================================== '======================================================================================== Private Sub btStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btStart.Click Try If objFileRead.ReadLine = Nothing Then MsgBox("No Accounts Available to show!", MsgBoxStyle.Information, MsgBoxStyle.DefaultButton2 = MsgBoxStyle.OkOnly) Return Else Do While (objFileRead.Peek() > -1) Loop lblAccounts.Text = objFileRead.ReadLine() 'objFileRead.Close() 'objFilename.Close() End If Catch ex As Exception MessageBox.Show(ex.Message) Finally 'objFileRead.Close() 'objFilename.Close() End Try End Sub Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load End Sub End Class

    Read the article

  • A F# tail-recursive question

    - by ksharp
    Recently, I'm learning F#. I try to solve problem in different ways. Like this: (* [0;1;2;3;4;5;6;7;8] -> [(0,1,2);(3,4,5);(6,7,8)] *) //head-recursive let rec toTriplet_v1 list= match list with | a::b::c::t -> (a,b,c)::(toTriplet_v1 t) | _ -> [] //tail-recursive let toTriplet_v2 list= let rec loop lst acc= match lst with | a::b::c::t -> loop t ((a,b,c)::acc) | _ -> acc loop list [] //tail-recursive(???) let toTriplet_v3 list= let rec loop lst accfun= match lst with | a::b::c::t -> loop t (fun ls -> accfun ((a,b,c)::ls)) | _ -> accfun [] loop list (fun x -> x) let funs = [toTriplet_v1; toTriplet_v2; toTriplet_v3]; funs |> List.map (fun x -> x [0..8]) |> List.iteri (fun i x -> printfn "V%d : %A" (i+1) x) I thought the results of V2 and V3 should be the same. But, I get the result below: V1 : [(0, 1, 2); (3, 4, 5); (6, 7, 8)] V2 : [(6, 7, 8); (3, 4, 5); (0, 1, 2)] V3 : [(0, 1, 2); (3, 4, 5); (6, 7, 8)] Why the results of V2 and V3 are different?

    Read the article

  • Replacing repetitively occuring loops with eval in Javascript - good or bad?

    - by Herc
    Hello stackoverflow! I have a certain loop occurring several times in various functions in my code. To illustrate with an example, it's pretty much along the lines of the following: for (var i=0;i<= 5; i++) { function1(function2(arr[i],i),$('div'+i)); $('span'+i).value = function3(arr[i]); } Where i is the loop counter of course. For the sake of reducing my code size and avoid repeating the loop declaration, I thought I should replace it with the following: function loop(s) { for (var i=0;i<= 5; i++) { eval(s); } } [...] loop("function1(function2(arr[i],i),$('div'+i));$('span'+i).value = function3(arr[i]);"); Or should I? I've heard a lot about eval() slowing code execution and I'd like it to work as fast as a proper loop even in the Nintendo DSi browser, but I'd also like to cut down on code. What would you suggest? Thank you in advance!

    Read the article

  • How to identify end of InputStream in java

    - by Vardhaman
    I am trying to read bytes from server using Socket program, ie I am using InputStream to read the bytes. If I pass the length size I am able to read the bytes, but I am not sure what may be the length. So I am not able initialize the byte array. Also I tried while (in.read() !=-1), I observered it loop works fine when the data is sent , but the next line after the loop is not executable , I feel its still looking for the data in the stream but there is no ata. If I close the Server connection , then my client will execute the next line followed to the loop. I am not sure where I am going wrong? this.in = socket.getInputStream(); int dataInt = this.in.read(); while(dataInt != -1){ System.out.print(","+i+"--"+dataInt); i++; dataInt = this.in.read(); } System.out.print("End Of loop"); I get the output as:- ,1--0,2--62,3--96,4--131,5--142,6--1,7--133,8--2,9--16,10--48,11--56,12--1,13--0,14--14,15--128,16--0,17--0,18--0,19--48,20--0,21--0,22--0,23--0,24--0,25--1,26--0,27--0,28--38,29--114,30--23,31--20,32--70,33--3,34--20,35--1,36--133,37--48,38--51,39--49,40--52,41--49,42--55,43--49,44--52,45--52,46--54,47--55,48--50,49--51,50--52,51--48,52--53,53--56,54--51,55--48,56--48,57--57,58--57,59--57,60--57,61--57,62--57,63--57,64--56 But no output for :- End Of loop Please guide how shall I close the loop? Looking forward for you response. Thanking you all in advance.

    Read the article

  • Empty value when iterating a dictionary with .iteritems() method

    - by ptpatil
    I am having some weird trouble with dictionaries, I am trying to iterate pairs from a dictionary to pass to another function. The loop for the iterator though for some reason always returns empty values. Here is the code: def LinktoCentral(self, linkmethod): if linkmethod == 'sim': linkworker = Linker.SimilarityLinker() matchlist = [] for k,v in self.ToBeMatchedTable.iteritems(): matchlist.append(k, linkworker.GetBestMatch(v, self.CentralDataTable.items())) Now if I insert a print line above the for loop: matchlist = [] print self.ToBeMatchedTable.items() for k,v in self.ToBeMatchedTable.iteritems(): matchlist.append(k, linkworker.GetBestMatch(v, self.CentralDataTable.items())) I get the data that is supposed to be in the dictionary printed out. The values of the dictionary are list objects. An example tuple I get from the dictionary when printing just above the for loop: >>> (1, ['AARP/United Health Care', '8002277789', 'PO Box 740819', 'Atlanta', 'GA', '30374-0819', 'Paper', '3676']) However, the for loop gives empty lists to the linkworker.GetBestMatch method. If I put a print line just below the for loop, here is what I get: Code: matchlist = [] for k,v in self.ToBeMatchedTable.iteritems(): print self.ToBeMatchedTable.items() matchlist.append(k, linkworker.GetBestMatch(v, self.CentralDataTable.items())) ## Place holder for line to send match list to display window return matchlist Result of first iteration: >>> (0, ['', '', '', '', '', '', '', '']) I literally have no idea whats going on, there is nothing else going on while this loop is executed. Any stupid mistakes I made?

    Read the article

  • Getting the innermost .NET Exception

    - by Rick Strahl
    Here's a trivial but quite useful function that I frequently need in dynamic execution of code: Finding the innermost exception when an exception occurs, because for many operations (for example Reflection invocations or Web Service calls) the top level errors returned can be rather generic. A good example - common with errors in Reflection making a method invocation - is this generic error: Exception has been thrown by the target of an invocation In the debugger it looks like this: In this case this is an AJAX callback, which dynamically executes a method (ExecuteMethod code) which in turn calls into an Amazon Web Service using the old Amazon WSE101 Web service extensions for .NET. An error occurs in the Web Service call and the innermost exception holds the useful error information which in this case points at an invalid web.config key value related to the System.Net connection APIs. The "Exception has been thrown by the target of an invocation" error is the Reflection APIs generic error message that gets fired when you execute a method dynamically and that method fails internally. The messages basically says: "Your code blew up in my face when I tried to run it!". Which of course is not very useful to tell you what actually happened. If you drill down the InnerExceptions eventually you'll get a more detailed exception that points at the original error and code that caused the exception. In the code above the actually useful exception is two innerExceptions down. In most (but not all) cases when inner exceptions are returned, it's the innermost exception that has the information that is really useful. It's of course a fairly trivial task to do this in code, but I do it so frequently that I use a small helper method for this: /// <summary> /// Returns the innermost Exception for an object /// </summary> /// <param name="ex"></param> /// <returns></returns> public static Exception GetInnerMostException(Exception ex) { Exception currentEx = ex; while (currentEx.InnerException != null) { currentEx = currentEx.InnerException; } return currentEx; } This code just loops through all the inner exceptions (if any) and assigns them to a temporary variable until there are no more inner exceptions. The end result is that you get the innermost exception returned from the original exception. It's easy to use this code then in a try/catch handler like this (from the example above) to retrieve the more important innermost exception: object result = null; string stringResult = null; try { if (parameterList != null) // use the supplied parameter list result = helper.ExecuteMethod(methodToCall,target, parameterList.ToArray(), CallbackMethodParameterType.Json,ref attr); else // grab the info out of QueryString Values or POST buffer during parameter parsing // for optimization result = helper.ExecuteMethod(methodToCall, target, null, CallbackMethodParameterType.Json, ref attr); } catch (Exception ex) { Exception activeException = DebugUtils.GetInnerMostException(ex); WriteErrorResponse(activeException.Message, ( HttpContext.Current.IsDebuggingEnabled ? ex.StackTrace : null ) ); return; } Another function that is useful to me from time to time is one that returns all inner exceptions and the original exception as an array: /// <summary> /// Returns an array of the entire exception list in reverse order /// (innermost to outermost exception) /// </summary> /// <param name="ex">The original exception to work off</param> /// <returns>Array of Exceptions from innermost to outermost</returns> public static Exception[] GetInnerExceptions(Exception ex) {     List<Exception> exceptions = new List<Exception>();     exceptions.Add(ex);       Exception currentEx = ex;     while (currentEx.InnerException != null)     {         exceptions.Add(ex);     }       // Reverse the order to the innermost is first     exceptions.Reverse();       return exceptions.ToArray(); } This function loops through all the InnerExceptions and returns them and then reverses the order of the array returning the innermost exception first. This can be useful in certain error scenarios where exceptions stack and you need to display information from more than one of the exceptions in order to create a useful error message. This is rare but certain database exceptions bury their exception info in mutliple inner exceptions and it's easier to parse through them in an array then to manually walk the exception stack. It's also useful if you need to log errors and want to see the all of the error detail from all exceptions. None of this is rocket science, but it's useful to have some helpers that make retrieval of the critical exception info trivial. Resources DebugUtils.cs utility class in the West Wind Web Toolkit© Rick Strahl, West Wind Technologies, 2005-2011Posted in CSharp  .NET  

    Read the article

  • Interpolation using a sprite's previous frame and current frame

    - by user22241
    Overview I'm currently using a method which has been pointed out to me is extrapolation rather than interolation. As a result, I'm also now looking into the possibility of using another method which is based on a sprite's position at it's last (rendered) frame and it's current one. Assuming an interpolation value of 0.5 this is, (visually), how I understand it should affect my sprite's position.... This is how I'm obtaining an inerpolation value: public void onDrawFrame(GL10 gl) { // Set/re-set loop back to 0 to start counting again loops=0; while(System.currentTimeMillis() > nextGameTick && loops < maxFrameskip) { SceneManager.getInstance().getCurrentScene().updateLogic(); nextGameTick += skipTicks; timeCorrection += (1000d / ticksPerSecond) % 1; nextGameTick += timeCorrection; timeCorrection %= 1; loops++; tics++; } interpolation = (float)(System.currentTimeMillis() + skipTicks - nextGameTick) / (float)skipTicks; render(interpolation); } I am then applying it like so (in my rendering call): render(float interpolation) { spriteScreenX = (spriteScreenX - spritePreviousX) * interpolation + spritePreviousX; spritePreviousX = spriteScreenX; // update and store this for next time } Results This unfortunately does nothing to smooth the movement of my sprite. It's pretty much the same as without the interpolation code. I can't get my head around how this is supposed to work and I honestly can't find any decent resources which explain this in any detail. My understanding of extrapolation is that when we arrive at the rendering call, we calculate the time between the last update call and the render call, and then adjust the sprite's position to reflect this time (moving the sprite forward) - And yet, this (Interpolation) is moving the sprite back, so how can this produce smooth results? Any advise on this would be very much appreciated. Edit I've implemented the code from OriginalDaemon's answer like so: @Override public void onDrawFrame(GL10 gl) { newTime = System.currentTimeMillis()*0.001; frameTime = newTime - currentTime; if ( frameTime > (dt*25)) frameTime = (dt*25); currentTime = newTime; accumulator += frameTime; while ( accumulator >= dt ) { SceneManager.getInstance().getCurrentScene().updateLogic(); previousState = currentState; t += dt; accumulator -= dt; } interpolation = (float) (accumulator / dt); render(); } Interpolation values are now being produced between 0 and 1 as expected (similar to how they were in my original loop) - however, the results are the same as my original loop (my original loop allowed frames to skip if they took too long to draw which I think this loop is also doing). I appear to have made a mistake in my previous logging, it is logging as I would expect it to (interpolated position does appear to be inbetween the previous and current positions) - however, the sprites are most definitely choppy when the render() skipping happens.

    Read the article

  • Create USB installer from the command line?

    - by j-g-faustus
    I'm trying to create a bootable USB image to install Ubuntu on a new computer. I have done this before following the "create USB drive" instructions for Ubuntu desktop, but I don't have an Ubuntu desktop available. How can I do the same using only the command line? Things I've tried: Create bootable USB on Mac OS X following the ubuntu.com "create USB drive" instructions for Mac: Doesn't boot. usb-creator: According to apt-cache search usb-creator and Wikipedia usb-creator only exists as a graphical tool. "Create manually" instructions at help.ubuntu.com: None of the files and directories described (e.g. casper, filesystem.manifest, menu.lst) exist in the ISO image, and I don't know what has replaced them. unetbootin scripting: Requires X server (graphics support) to run, even when fully scripted. (The command sudo unetbootin lang=en method=diskimage isofile=~/ubuntu-10.10-server-amd64.iso installtype=USB targetdrive=/dev/sdg1 autoinstall=yes gives an error message unetbootin: cannot connect to X server.) Update Also tried GRUB fiddling: Merging information from pendrivelinux.com a related question on the Linux Stackexchange and a grub configuration example I was able to get halfway there - it booted from USB, displayed the grub menu and started the installation, but installation did not complete. For reference, this is the closest I got: sudo su # mount USB pen mount /dev/sd[X]1 /media/usb # install GRUB grub-install --force --no-floppy --root-directory=/media/usb /dev/sd[X] # copy ISO image to USB cp ~/ubuntu-10.10-server-amd64.iso /media/usb # mount ISO image, copy existing grub.cfg mount ~/ubuntu-10.10-server-amd64.iso /media/iso/ -o loop cp /media/iso/boot/grub/grub.cfg /media/usb/boot/grub/ I then edited /media/usb/boot/grub.cfg to add an .iso loopback, example grub entry: menuentry "Install Ubuntu Server" { set gfxpayload=keep loopback loop /ubuntu-10.10-server-amd64.iso linux (loop)/install/vmlinuz file=(loop)/preseed/ubuntu-server.seed iso-scan/filename=/ubuntu-10.10-server-amd64.iso quiet -- initrd (loop)/install/initrd.gz } When booting from USB, this would give me the Grub boot menu and start the installer, but the installer gave up after a couple of screens complaining that it couldn't find the CD-ROM drive. (Naturally, as the box I'm installing on doesn't have an optical drive.) I resolved this particular issue by giving up and doing the "create USB drive" routine using the Ubuntu Live desktop CD (on a computer that does have an optical drive), then the USB install works. But I expect that there is some way to do this from the command line of an Ubuntu system without X server and without an optical drive, so the question still stands. Does anyone know how?

    Read the article

< Previous Page | 83 84 85 86 87 88 89 90 91 92 93 94  | Next Page >