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  • Storing data in a MySQL database using MySQL & PHP

    - by comma
    I'm new to PHP and MySQL and I'm trying to store a users entered data from the following fields $skill, $experience, $years which a user can also add additional fields of $skill, $experience, $years if needed so in instead of 1 of each field there might be multiples of each field. I was wondering how can I store the fields in my MySQL database using PHP and MySQL? I have the following script but I know its wrong. can some one help me fix the script listed below? Here is the PHP and MySQL code. $skill = serialize($_POST['skill']); $experience = serialize($_POST['experience']); $years = serialize($_POST['years']); for (($s = 0; $s < count($skill); $s++) && ($x = 0; $x < count($experience); $x++) && ($g = 0; $g < count($years); $g++)){ $mysqli = mysqli_connect("localhost", "root", "", "sitename"); $query1 = "INSERT INTO learned_skills (skill, experience, years) VALUES ('" . $skill[$s] . "', '" . $experience[$x] . "', '" . $years[$g] . "')"; if (!mysqli_query($mysqli, $query1)) { print mysqli_error($mysqli); return; } } Here is my MySQL table. CREATE TABLE learned_skills ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, skill TEXT NOT NULL, experience TEXT NOT NULL, years INT NOT NULL, PRIMARY KEY (id) ); CREATE TABLE u_skills ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, skill_id INT UNSIGNED NOT NULL, users_id INT UNSIGNED NOT NULL, PRIMARY KEY (id) );

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  • Why is my code stopping and not returning an exception?

    - by BeckyLou
    I have some code that starts a couple of threads to let them execute, then uses a while loop to check for the current time passing a set timeout period, or for the correct number of results to have been processed (by checking an int on the class object) (with a Thread.Sleep() to wait between loops) Once the while loop is set to exit, it calls Abort() on the threads and should return data to the function that calls the method. When debugging and stepping through the code, I find there can be exceptions in the code running on the separate threads, and in some cases I handle these appropriately, and at other times I don't want to do anything specific. What I have been seeing is that my code goes into the while loop and the thread sleeps, then nothing is returned from my function, either data or an exception. Code execution just stops completely. Any ideas what could be happening? Code sample: System.Threading.Thread sendThread = new System.Threading.Thread(new System.Threading.ThreadStart(Send)); sendThread.Start(); System.Threading.Thread receiveThread = new System.Threading.Thread(new System.Threading.ThreadStart(Receive)); receiveThread.Start(); // timeout Int32 maxSecondsToProcess = this.searchTotalCount * timeout; DateTime timeoutTime = DateTime.Now.AddSeconds(maxSecondsToProcess); Log("Submit() Timeout time: " + timeoutTime.ToString("yyyyMMdd HHmmss")); // while we're still waiting to receive results & haven't hit the timeout, // keep the threads going while (resultInfos.Count < this.searchTotalCount && DateTime.Now < timeoutTime) { Log("Submit() Waiting..."); System.Threading.Thread.Sleep(10 * 1000); // 1 minute } Log("Submit() Aborting threads"); // <== this log doesn't show up sendThread.Abort(); receiveThread.Abort(); return new List<ResultInfo>(this.resultInfos.Values);

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  • Spring MVC: Where to place validation and how to validation entity references.

    - by arrages
    Let's say I have the following command bean for creating a user: public class CreateUserCommand { private String userName; private String email; private Integer occupationId; pirvate Integer countryId; } occupationId and countryId are drop down selected values on the form. They map to an entity in the database (Occupation, Country). This command object is going to be fed to a service facade like so: userServiceFacade.createUser(CreateUserCommand command); This facade will construct a user entity to be sent to the actual service. So I suppose that in the facade layer I will have to make several dao calls to map all the lookup properties of the User entity. Based on this what is the best strategy to validate that occupationId and countryId map to real entities? Where is the best place to perform this validation? There is the spring validator but I am not sure this is the best place for this, for one I am wary of this method as validation is tied to the web tier, but also that means I would need to make the dao calls in the validator for validation but I would need to call the dao's in the facade layer again when the command - entity translation occurs. Is there anything I can do better? Thanks.

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  • How to increment the string value during run time without using dr.read() and store it in the oledb

    - by sameer
    Here is my code, everything is working fine the only problem is with the ReadData() method in which i want the string value to be increment i.e AM0001,AM0002,AM0003 etc. This is happening but only one time the value is getting increment to AM0001, the second time the same value i.e AM0001 is getting return. Due to this i am getting a error from oledb because of AM0001 is a primary key field. enter code here: class Jewellery : Connectionstr { string lmcode = null; public string LM_code { get { return lmcode;} set { lmcode = ReadData();} } string mname; public string M_Name { get { return mname; } set { mname = value;} } string desc; public string Desc { get { return desc; } set { desc = value; } } public string ReadData() { string jid = string.Empty; string displayString = string.Empty; String query = "select max(LM_code)from Master_Accounts"; Datamanager.RunExecuteReader(Constr,query); if (string.IsNullOrEmpty(jid)) { jid = "AM0000";//This string value has to increment at every time, but it is getting increment only one time. } int len = jid.Length; string split = jid.Substring(2, len - 2); int num = Convert.ToInt32(split); num++; displayString = jid.Substring(0, 2) + num.ToString("0000"); return displayString; } public void add() { String query ="insert into Master_Accounts values ('" + LM_code + "','" + M_Name + "','" + Desc + "')"; Datamanager.RunExecuteNonQuery(Constr , query); } Any help will be appreciated.

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  • Problems with Database Search Code (asp.net vb)

    - by Phil
    Here is a sample of my database search code: Dim sql As String = "Select * From Table Where " Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim andor As Boolean = AndOr1.SelectedValue 'selection can be AND or OR (0 / 1) 'Code for when the user selects AND If NameSearch.Text.ToString IsNot String.Empty And andor = 0 Then sql += "Surname LIKE '%" & name & "%' AND " End If If EmailSearch.Text.ToString IsNot String.Empty And andor = 0 Then sql += "Email LIKE '%" & email & "%' AND " End If If CitySearchBox.Text.ToString IsNot String.Empty And andor = 0 Then sql += "City LIKE '%" & city & "%' AND " End If 'Code for when the user selects OR If NameSearch.Text.ToString IsNot String.Empty And andor = 1 Then sql += "(Surname LIKE '%" & name & "%' OR " End If If EmailSearch.Text.ToString IsNot String.Empty And andor = 1 Then sql += "Email LIKE '%" & email & "%') OR " End If If CitySearchBox.Text.ToString IsNot String.Empty And andor = 1 Then sql += "(City LIKE '%" & city & "%' OR " End If sql = CleanString(sql) End Sub When the user selects AND (as andor.selectedvalue(0)) then the sql is produced fine like this; Select * From Table Where Surname LIKE '%test%' AND Email LIKE '%test%' AND City LIKE '%test%' But if the user selects OR (as andor.selectedvalue(1)), nothing is outputted except; Select * From Table Where Im sure the controls have values so are not string.empty and when the user selects OR the correct value 1 is being assigned to andor.

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  • Flex component setActualSize

    - by dlots
    I am a little confused about the setActualSize method. It appears from what I've read, that if it is not called on a component by its parent, the component will not be rendered. So it appears that setActualSize is a critical method that is directly bound to rendering the UIComponent. It also appears that the width and height properties of UIComponent override the functionality of the width and height properties of flash.display.DisplayObject, in that they are not directly bound to the rendering of the object but are virtual values that are mainly used by the getExplicitOrMeasured when the parent of the component calls the component's setActualSize method. So the question are: 1) Why isn't the default behavior of every component to just call setActualSize(getExplicitOrMeasuredWidth(),getExplicitOrMeasuredHeight()) on itself? 2) I guess this question stems from the above question and the behavior as I understand it as described above: does setActualSize change the visibility of the component? It appears that that the behavior is that a component is not rendered until setActualSize is called, but if it contains display object children itself (expected behavior as it can calculate measure on itself) and is added to the display list, the only reason why flash isn't rendering it, is because its not visible. 3) Relating to question #1, does updateDisplayList of UIComponent have a method that goes through its children calling setActualSize on each of them?

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  • jquery form validation, and submit-on-change

    - by Bee
    I want to make all my settings forms across my site confirm that changes are saved, kinda like facebook does if you make changes in a form and then try to navigate away without saving. So I'm disabling the submit button on the forms only enabling if the values change. I then prompt the user to hit save before they leave the page in the case that they do have changes pending. var form = $('form.edit'); if(form.length > 0) { var orig_str = form.serialize(); $(':submit',form).attr('disabled','disabled'); form.on('change keyup', function(){ if(form.serialize() == orig_str) { setConfirmUnload(false); $(':submit',form).attr('disabled','disabled'); } else { setConfirmUnload(true); $(':submit',form).removeAttr('disabled') } }); $('input[type=submit]').click(function(){ setConfirmUnload(false); }); } function setConfirmUnload(on) { window.onbeforeunload = (on) ? unloadMessage : null; } function unloadMessage() { return 'If you navigate away from this page without saving your changes, they will be lost.'; } One of these forms needs some additional validation which I do using jQuery.validate library. e.g. if i wanted to ensure the user can't double submit the form on accident by double clicking on submit or somesuch (the actual validation in question is for a credit-card form and not this simple): $('form').validate({ submitHandler: function(form) { $(':submit', form).attr('disabled','disabled'); form.submit(); } }); Unfortunately both bits are trying to bind to submit button and they're interfering with each other such that the submit button remains disabled no matter what I do and it is impossible to submit the form at all. Is there some way to chain the validations together or something? Or some other way to avoid re-writing the validation code to repeat the "did you change anything in the form" business?

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  • Reading lines of data from text files using java

    - by razshan
    I have a text file with x amount of lines. each line holds a integer number. When the user clicks a button, an action is performed via actionlistener where it should list all the values as displayed on the text file. However, right now I have linenum set to 10 implying I already told the code that just work with 10 lines of the text file. So, if my text file has only 3 rows/lines of data...it will list those lines and for rest of the other 7 lines, it will spit out "null". I recall there is a way to use ellipsis to let the program know that you don't know the exact value but at the end it calculates it based on the given information. Where my given information will the number of lines with numbers(data). Below is part of the code. private class thehandler implements ActionListener{ public void actionPerformed(ActionEvent event){ BufferedReader inputFile=null; try { FileReader freader =new FileReader("Data.txt"); inputFile = new BufferedReader(freader); String MAP = ""; int linenum=10; while(linenum > 0) { linenum=linenum-1; MAP = inputFile.readLine();//read the next line until the specfic line is found System.out.println(MAP); } } catch( Exception y ) { y.printStackTrace(); } }}

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  • Grouping arrays with consecutive keys

    - by KPL
    Hello people, I've an array like this - Array ( [16] => 424 [17] => 404 [18] => 416 [21] => 404 [22] => 456 [23] => 879 [28] => 456 [29] => 456 [32] => 123 [35] => 465 ) The output of this array would be Array ( [0] => Array ( ['start'] => 16 ['stop'] => 18 ) [1] => Array ( ['start'] => 21 ['stop'] => 23 ) [2] => Array ( ['start'] => 28 ['stop'] => 29 ) [3] => Array ( ['start'] => 32 ['stop'] => 33 ) [4] => Array ( ['start'] => 35 ['stop'] => 36 ) ) I don't really need the values. Just grouping the keys. And if consecutive integer doesn't exist for a particular key(like for [32] and [35]), 'stop' should be the consecutive integer. Thank you all for help.

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  • Pointers and Addresses in C

    - by Mohit
    #include "stdio.h" main() { int i=3,*x; float j=1.5,*y; char k='c',*z; x=&i; y=&j; z=&k; printf("\nAddress of x= %u",x); printf("\nAddress of y= %u",y); printf("\nAddress of z= %u",z); x++; y++;y++;y++;y++; z++; printf("\nNew Address of x= %u",x); printf("\nNew Address of y= %u",y); printf("\nNew Address of z= %u",z); printf("\nNew Value of i= %d",i); printf("\nNew Value of j= %f",j); printf("\nNew Value of k= %c\n",k); } Output: Address of x= 3219901868 Address of y= 3219901860 Address of z= 3219901875 New Address of x= 3219901872 New Address of y= 3219901876 New Address of z= 3219901876 New Value of i= 3 New Value of j= 1.500000 New Value of k= c The new address of variable y and z are same. How can two variables have same address and et have different values? Note: I used gcc compiler on Ubuntu 9.04

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  • C Programming. How to deep copy a struct?

    - by user69514
    I have the following two structs where "child struct" has a "rusage struct" as an element. Then I create two structs of type "child" let's call them childA and childB How do I copy just the rusage struct from childA to childB? typedef struct{ int numb; char *name; pid_t pid; long userT; long systemT; struct rusage usage; }child; typedef struct{ struct timeval ru_utime; /* user time used */ struct timeval ru_stime; /* system time used */ long ru_maxrss; /* maximum resident set size */ long ru_ixrss; /* integral shared memory size */ long ru_idrss; /* integral unshared data size */ long ru_isrss; /* integral unshared stack size */ long ru_minflt; /* page reclaims */ long ru_majflt; /* page faults */ long ru_nswap; /* swaps */ long ru_inblock; /* block input operations */ long ru_oublock; /* block output operations */ long ru_msgsnd; /* messages sent */ long ru_msgrcv; /* messages received */ long ru_nsignals; /* signals received */ long ru_nvcsw; /* voluntary context switches */ long ru_nivcsw; /* involuntary context switches */ }rusage; I did the following, but I guess it copies the memory location, because if I changed the value of usage in childA, it also changes in childB. memcpy(&childA,&childB, sizeof(rusage)); I know that gives childB all the values from childA. I have already taken care of the others fields in childB, I just need to be able to copy the rusage struct called usage that resides in the "child" struct.

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  • Strange results while measuring delta time on Linux

    - by pachanga
    Folks, could you please explain why I'm getting very strange results from time to time using the the following code: #include <unistd.h> #include <sys/time.h> #include <time.h> #include <stdio.h> int main() { struct timeval start, end; long mtime, seconds, useconds; while(1) { gettimeofday(&start, NULL); usleep(2000); gettimeofday(&end, NULL); seconds = end.tv_sec - start.tv_sec; useconds = end.tv_usec - start.tv_usec; mtime = ((seconds) * 1000 + useconds/1000.0) + 0.5; if(mtime > 10) printf("WTF: %ld\n", mtime); } return 0; } (You can compile and run it with: gcc test.c -o out -lrt && ./out) What I'm experiencing is sporadic big values of mtime variable almost every second or even more often, e.g: $ gcc test.c -o out -lrt && ./out WTF: 14 WTF: 11 WTF: 11 WTF: 11 WTF: 14 WTF: 13 WTF: 13 WTF: 11 WTF: 16 How can this be possible? Is it OS to blame? Does it do too much context switching? But my box is idle( load average: 0.02, 0.02, 0.3). Here is my Linux kernel version: $ uname -a Linux kurluka 2.6.31-21-generic #59-Ubuntu SMP Wed Mar 24 07:28:56 UTC 2010 i686 GNU/Linux

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  • lapply slower than for-loop when used for a BiomaRt query. Is that expected?

    - by ptocquin
    I would like to query a database using BiomaRt package. I have loci and want to retrieve some related information, let say description. I first try to use lapply but was surprise by the time needed for the task to be performed. I thus tried a more basic for-loop and get a faster result. Is that expected or is something wrong with my code or with my understanding of apply ? I read other posts dealing with *apply vs for-loop performance (Here, for example) and I was aware that improved performance should not be expected but I don't understand why performance here is actually lower. Here is a reproducible example. 1) Loading the library and selecting the database : library("biomaRt") athaliana <- useMart("plants_mart_14") athaliana <- useDataset("athaliana_eg_gene",mart=athaliana) 2) Querying the database : loci <- c("at1g01300", "at1g01800", "at1g01900", "at1g02335", "at1g02790", "at1g03220", "at1g03230", "at1g04040", "at1g04110", "at1g05240" ) I create a function for the use in lapply : foo <- function(loci) { getBM("description","tair_locus",loci,athaliana) } When I use this function on the first element : > system.time(foo(cwp_loci[1])) utilisateur système écoulé 0.020 0.004 1.599 When I use lapply to retrieve the data for all values : > system.time(lapply(loci, foo)) utilisateur système écoulé 0.220 0.000 16.376 I then created a new function, adding a for-loop : foo2 <- function(loci) { for (i in loci) { getBM("description","tair_locus",loci[i],athaliana) } } Here is the result : > system.time(foo2(loci)) utilisateur système écoulé 0.204 0.004 10.919 Of course, this will be applied to a big list of loci, so the best performing option is needed. I thank you for assistance. EDIT Following recommendation of @MartinMorgan Simply passing the vector loci to getBM greatly improves the query efficiency. Simpler is better. > system.time(lapply(loci, foo)) utilisateur système écoulé 0.236 0.024 110.512 > system.time(foo2(loci)) utilisateur système écoulé 0.208 0.040 116.099 > system.time(foo(loci)) utilisateur système écoulé 0.028 0.000 6.193

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  • Passing models between controllers in MVC4

    - by wtfsven
    I'm in the middle of my first foray into web development with MVC4, and I've run into a problem that I just know is one of the core issues in web development in general, but can't seem to wrap my mind around it. So I have two models: Employee and Company. Employee has a Company, therefore /Employee/Create contains a field that is either a dropdown list for selecting an existing Company, or an ActionLink to /Company/Create if none exists. But here's the issue: If a user has to create a Company, I need to preserve the existing Employee model across both Views--over to /Company/Create, then back to /Employee/Create. So my first approach was to pass the Employee model to /Company/Create with a @Html.ActionLink("Add...", "Create", "Organization", Model , null), but then when I get to Company's Create(Employee emp), all of emp's values are null. The second problem is that if I try to come back to /Employee/Create, I'd be passing back an Employee, which would resolve to the POST Action. Basically, the whole idea is to save the state of the /Employee/Create page, jump over to /Company/Create to create a Company record, then back to /Employee/Create to finish creating the Employee. I know there is a well understood solution to this because , but I can't seem to phase it well enough to get a good Google result out of it. I've though about using Session, but it seems like doing so would be a bit of a kludge. I'd really like an elegant solution to this.

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  • Efficiently select top row for each category in the set

    - by VladV
    I need to select a top row for each category from a known set (somewhat similar to this question). The problem is, how to make this query efficient on the large number of rows. For example, let's create a table that stores temperature recording in several places. CREATE TABLE #t ( placeId int, ts datetime, temp int, PRIMARY KEY (ts, placeId) ) -- insert some sample data SET NOCOUNT ON DECLARE @n int, @ts datetime SELECT @n = 1000, @ts = '2000-01-01' WHILE (@n>0) BEGIN INSERT INTO #t VALUES (@n % 10, @ts, @n % 37) IF (@n % 10 = 0) SET @ts = DATEADD(hour, 1, @ts) SET @n = @n - 1 END Now I need to get the latest recording for each of the places 1, 2, 3. This way is efficient, but doesn't scale well (and looks dirty). SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 1 ORDER BY ts DESC ) t1 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 2 ORDER BY ts DESC ) t2 UNION ALL SELECT * FROM ( SELECT TOP 1 placeId, temp FROM #t WHERE placeId = 3 ORDER BY ts DESC ) t3 The following looks better but works much less efficiently (30% vs 70% according to the optimizer). SELECT placeId, ts, temp FROM ( SELECT placeId, ts, temp, ROW_NUMBER() OVER (PARTITION BY placeId ORDER BY ts DESC) rownum FROM #t WHERE placeId IN (1, 2, 3) ) t WHERE rownum = 1 The problem is, during the latter query execution plan a clustered index scan is performed on #t and 300 rows are retrieved, sorted, numbered, and then filtered, leaving only 3 rows. For the former query three times one row is fetched. Is there a way to perform the query efficiently without lots of unions?

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  • Behavior of Struts2 and convention-plugin when there is Index(extends ActionSupport)

    - by hanishi
    We have an Action class named 'Index' immediately under com.example.common.action and is annotated @ParentPackage('default') which is declared in package directive in struts.xml and has "/" for its namespace and extends "struts-default". It also declares @Result so that it responses with jsp files corresponding the string values returned by its execute() method. In our struts.xml, the following struts setting is configured along with other necessary configurations that are needed for convention-plugin. <constant name="struts.action.extension" value=","/> When accessing /my_context/none_existing_path, the request apparently hits this Index class and the contents of the jsp declared in the Index's @Result section gets returned. However, if we provide /my_context/, we receive the following error: HTTP Status 404-There is no Action mapped for namespace[/] and action name [] associated with context path [/my_context]. We want to know the reason why accessing /my_context/none_existing_path, where none_existing_path has no matching action, can fallback to Index class, but error is returned when when the URL requested is just /my_context/. Currently, our convention-plugin settings are declared as follows: <constant name="struts.convention.package.locators.basePackage" value="com.example"/> <constant name="struts.convention.package.locators" value="action"/> Strangely, if we changed the value of the struts.convention.package.locators.basePackage to om.example.common, in which the aforementioned Index file can be immediately found by narrowing the search scope, requesting /my_context/ displays the content of the jsps declared in @Result section of the Index class. However, as our action classes are distributed throughout the com.example.[a-z].action packages, where [a-z] represents the large volume of directories we have in our package structure, we cannot use this trick as a workaround. We have also tried placing index.jsp at the top level of the class path, and have the index.jsp redirect to /my_context/index, which worked but not what we want. Could this be a bug? We appreciate your responses. Thank you in advance. EDIT: JIRA registered, problem solved (from Struts 2.3.12 up)

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  • When I try to pass large amounts of information using jquery $.ajax(post) method. it throws potenti

    - by dotnetrocks
    I am trying to create a preview window for my texteditor in my blog page. I need to send the content to the server to clean up the text entered before I can preview it on the preview window. I was trying to use $.ajax({ type: method, url: url, data: values, success: LoadPageCallback(targetID), error: function(msg) { $('#' + targetID).attr('innerHTML', 'An error has occurred. Please try again.'); } }); Whenever I tried to click on the preview button it returns an XMLHTTPRequest error. The error description - Description: Request Validation has detected a potentially dangerous client input value, and processing of the request has been aborted. This value may indicate an attempt to compromise the security of your application, such as a cross-site scripting attack. You can disable request validation by setting validateRequest=false in the Page directive or in the configuration section. However, it is strongly recommended that your application explicitly check all inputs in this case. The ValidateRequest for the page is set to false. Is there a way I can set validaterequest to false for the ajax call.Please advise Thank you for reading my post.

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  • Change index order in array (php)

    - by Trikks
    Hi Been kind of stuck on this one for a while now, so any help would be appreciated. I have one array (left) that contains a list of elements, the goal is to sort another arrays (right) keys with the values from the left array. The left array Array ( [0] => ID [1] => FirstName [2] => LastName [3] => Address ) The right array Array ( [0] => Array ( [FirstName] => Pim [Address] => Finland [LastName] => Svensson [ID] => 3 ) [1] => Array ( [FirstName] => Emil [Address] => Sweden [LastName] => Malm [ID] => 5 ) ) What I'm trying to accomplish would be similar to this Array ( [0] => Array ( [ID] => 3 [FirstName] => Pim [LastName] => Svensson [Address] => Finland ) Anyone? :) Oh, I'm running php 5.3, if it helps!

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  • power and modulo on the fly for big numbers

    - by user unknown
    I raise some basis b to the power p and take the modulo m of that. Let's assume b=55170 or 55172 and m=3043839241 (which happens to be the square of 55171). The linux-calculator bc gives the results (we need this for control): echo "p=5606;b=55171;m=b*b;((b-1)^p)%m;((b+1)^p)%m" | bc 2734550616 309288627 Now calculating 55170^5606 gives a somewhat large number, but since I have to do a modulooperation, I can circumvent the usage of BigInt, I thought, because of: (a*b) % c == ((a%c) * (b%c))%c i.e. (9*7) % 5 == ((9%5) * (7%5))%5 => 63 % 5 == (4 * 2) %5 => 3 == 8 % 5 ... and a^d = a^(b+c) = a^b * a^c, therefore I can divide b+c by 2, which gives, for even or odd ds d/2 and d-(d/2), so for 8^5 I can calculate 8^2 * 8^3. So my (defective) method, which always cut's off the divisor on the fly looks like that: def powMod (b: Long, pot: Int, mod: Long) : Long = { if (pot == 1) b % mod else { val pot2 = pot/2 val pm1 = powMod (b, pot, mod) val pm2 = powMod (b, pot-pot2, mod) (pm1 * pm2) % mod } } and feeded with some values, powMod (55170, 5606, 3043839241L) res2: Long = 1885539617 powMod (55172, 5606, 3043839241L) res4: Long = 309288627 As we can see, the second result is exactly the same as the one above, but the first one looks quiet different. I'm doing a lot of such calculations, and they seem to be accurate as long as they stay in the range of Int, but I can't see any error. Using a BigInt works as well, but is way too slow: def calc2 (n: Int, pri: Long) = { val p: BigInt = pri val p3 = p * p val p1 = (p-1).pow (n) % (p3) val p2 = (p+1).pow (n) % (p3) print ("p1: " + p1 + " p2: " + p2) } calc2 (5606, 55171) p1: 2734550616 p2: 309288627 (same result as with bc) Can somebody see the error in powMod?

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  • Rationale in selecting Hash Key type

    - by Amrish
    Guys, I have a data structure which has 25 distinct keys (integer) and a value. I have a list of these objects (say 50000) and I intend to use a hash table to store/retrieve them. I am planning to take one of these approaches. Create a integer hash from these 25 integer keys and store it on a hash table. (Yeah! I have some means to handle collisions) Make a string concatenation on the individual keys and use it as a hash key for the hash table. For example, if the key values are 1,2,4,6,7 then the hash key would be "12467". Assuming that I have a total of 50000 records each with 25 distinct keys and a value, then will my second approach be a overkill when it comes to the cost of string comparisons it needs to do to retrieve and insert a record? Some more information! Each bucket in the hash table is a balanced binary tree. I am using the boost library's hash_combine method to create the hash from the 25 keys.

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  • How to convert "0" and "1" to false and true

    - by Chris
    I have a method which is connecting to a database via Odbc. The stored procedure which I'm calling has a return value which from the database side is a 'Char'. Right now I'm grabbing that return value as a string and using it in a simple if statement. I really don't like the idea of comparing a string like this when only two values can come back from the database, 0 and 1. OdbcCommand fetchCommand = new OdbcCommand(storedProc, conn); fetchCommand.CommandType = CommandType.StoredProcedure; fetchCommand.Parameters.AddWithValue("@column ", myCustomParameter); fetchCommand.Parameters.Add("@myReturnValue", OdbcType.Char, 1). Direction = ParameterDirection.Output; fetchCommand.ExecuteNonQuery(); string returnValue = fetchCommand.Parameters["@myReturnValue"].Value.ToString(); if (returnValue == "1") { return true; } What would be the proper way to handle this situation. I've tried 'Convert.ToBoolean()' which seemed like the obvious answer but I ran into the 'String was not recognized as a valid Boolean. ' exception being thrown. Am I missing something here, or is there another way to make '1' and '0' act like true and false? Thanks!

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  • Display contact pictures in list view

    - by user1068400
    I need to display the contact pictures in a list view. In my custom_row_view.xml I have: <ImageView android:id="@+id/contact_image" android:layout_width="60dp" android:layout_height="50dp" /> and then in my activity i have: final SimpleAdapter adapter = new SimpleAdapter( this, list, R.layout.custom_row_view, new String[] {"avatar","telnumber","date","name","message","sent"}, new int[] {R.id.contact_image,R.id.text1,R.id.text2,R.id.text3,R.id.text4,R.id.isent} ); I have a hashmap HashMap temp2 = new HashMap(); where i put all the values of each line. ("list" is a list of Hashmap) But when I do: Cursor photo2 = managedQuery( Data.CONTENT_URI, new String[] {Photo.PHOTO}, // column for the blob Data._ID + "=?", // select row by id new String[]{photoid}, // filter by photoId null); Bitmap photoBitmap = null; if(photo2.moveToFirst()) { byte[] photoBlob = photo2.getBlob(photo2.getColumnIndex(Photo.PHOTO)); photoBitmap = BitmapFactory.decodeByteArray(photoBlob, 0, photoBlob.length); if (photoBitmap != null) temp2.put("avatar",photoBitmap); else temp2.put("avatar",R.drawable.unknowncontact); } photo2.close(); Nothing is displayed! "temp2.put("avatar",photoBitmap);" does not display anything but when I try to display something from the drawable folder it works!!! Please help me, i have been locked on this problem for several days! Thanks a lot!

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  • Understanding C++ pointers (when they point to a pointer)

    - by Stephano
    I think I understand references and pointers pretty well. Here is what I (think I) know: int i = 5; //i is a primitive type, the value is 5, i do not know the address. int *ptr; //a pointer to an int. i have no way if knowing the value yet. ptr = &i; //now i have an address for the value of i (called ptr) *ptr = 10; //go get the value stored at ptr and change it to 10 Please feel free to comment or correct these statements. Now I'm trying to make the jump to arrays of pointers. Here is what I do not know: char **char_ptrs = new char *[50]; Node **node_ptrs = new Node *[50]; My understanding is that I have 2 arrays of pointers, one set of pointers to chars and one to nodes. So if I wanted to set the values, I would do something like this: char_ptrs[0] = new char[20]; node_ptrs[0] = new Node; Now I have a pointer, in the 0 position of my array, in each respective array. Again, feel free to comment here if I'm confused. So, what does the ** operator do? Likewise, what is putting a single * next to the instantiation doing (*[50])? (what is that called exactly, instantiation?)

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  • Java Newbie can't do simple Math, operator error

    - by elguapo-85
    Trying to do some really basic math here, but my lack of understanding of Java is causing some problems for me. double[][] handProbability = new double[][] {{0,0,0},{0,0,0},{0,0,0}}; double[] handProbabilityTotal = new double[] {0,0,0}; double positivePot = 0; double negativePot = 0; int localAhead = 0; int localTied = 1; int localBehind = 2; //do some stuff that adds values to handProbability and handProbabilityTotal positivePot = (handProbability[localBehind][localAhead] + (handProbability[localBehind][localTied] / 2.0) + (handProbability[localTied][localAhead] / 2.0) ) / (handProbabilityTotal[localBehind] + (handProbability[localTied] / 2.0)); negativePot = (handProbability[localAhead][localBehind] + (handProbability[localAhead][localTied] / 2.0) + (handProbability[localTied][localBehind] / 2.0) ) / (handProbabilityTotal[localAhead] + (handProbabilityTotal[localTied] / 2.0)); The last two lines are giving me problems (sorry for their lengthiness). Compiler Errors: src/MyPokerClient/MyPokerClient.java:180: operator / cannot be applied to double[],double positivePot = ( handProbability[localBehind][localAhead] + (handProbability[localBehind][localTied] / 2.0) + (handProbability[localTied][localAhead] / 2.0) ) / (handProbabilityTotal[localBehind] + (handProbability[localTied] / 2.0) ); ^ src/MyPokerClient/MyPokerClient.java:180: operator + cannot be applied to double, positivePot = ( handProbability[localBehind][localAhead] + (handProbability[localBehind][localTied] / 2.0) + (handProbability[localTied][localAhead] / 2.0) ) / (handProbabilityTotal[localBehind] + (handProbability[localTied] / 2.0) ); ^ src/MyPokerClient/MyPokerClient.java:180: operator / cannot be applied to double, positivePot = ( handProbability[localBehind][localAhead] + (handProbability[localBehind][localTied] / 2.0) + (handProbability[localTied][localAhead] / 2.0) ) / (handProbabilityTotal[localBehind] + (handProbability[localTied] / 2.0) ); Not really sure what the problem is. You shouldn't need anything special for basic math, right?

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  • How do you convert bytes of bitmap into x, y location of pixels?

    - by Jon
    I have a win32 program that creates a bitmap screenshot. I am trying to figure out the x and y coordinates of the bmBits. Below is the code I have so far: UINT32 nScreenX = GetSystemMetrics(SM_CXSCREEN); UINT32 nScreenY = GetSystemMetrics(SM_CYSCREEN); HDC hdc = GetDC(NULL); HDC hdcScreen = CreateCompatibleDC(hdc); HBITMAP hbmpScreen = CreateDIBSection( hdcDesk, ( BITMAPINFO* )&bitmapInfo.bmiHeader,DIB_RGB_COLORS, &bitmapDataPtr, NULL, 0 ); SelectObject(hdcScreen, hbmpScreen); BitBlt(hdcScreen, 0, 0, nScreenX , nScreenY , hdc, 0, 0, SRCCOPY); ReleaseDC(NULL, hdc); BITMAP bmpScreen; GetObject(hbmpScreen, sizeof(bmpScreen), &bmpScreen); DWORD *pScreenPixels = (DWORD*)bmpScreen.bmBits, UINT32 x = 0; UINT32 y = 0; UINT32 nCntPixels = nScreenX * nScreenY; for(int n = 0; n < nCntPixels; n++) { x = n % nScreenX; y = n / nScreenX; //do stuff with the x and y vals } The code seem correct to me but, when I use this code the x and y values appear to be off. Where does the first pixel of bmBits start? When x and y are both 0. Is that the top left, bottom left, bottom right or top right? Thanks.

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