c# - Issue when trying to determine common elements in two List<T> -

-

i have class, called classx purposes of question, declared follows:

class x  {      public guid id { get; set; }      public string name { get; set; }      public string description { get; set; }  }

if have 2 instances (instanceone , instancetwo) of list<t> of these classes, how can find elements same in both instances:

assume there 2 elements in instanceone , 4 elements in instancetwo. 2 of elements same (as defined fact have same guid id) in each of instances

i thought should able linq way isn't doing me

// what's common 2 instances? var commonelements = (     in instancetwo     join b in instanceone on a.id equals b.id     select b).tolist();  // what's not in instanceone , in instancetwo?  var notininstanceone = instancetwo.except(commonelements)

in situation instancetwo superset of instanceone may not case should able flip original linq statement elements in instanceone not in instancetwo viz:

var notininstancetwo = instanceone.except(commonelements)

frustratingly original linq statement (where attempt determine common elements) isn't working, can spot i'm doing wrong?

edit 2012-06-08 11:00 utc

per @nikhil agrawal , @trust me - i'm doctor have used intersect method doesn't produce expected results:

    var commonitems = instancetwo.intersect(instanceone); // returns nothing     var itemsintwonotone= instancetwo.except(instanceone); // returns in instancetwo

fwiw implementation of equals() method is:

public bool equals(guid x, guid y) {    if (x == y)    {       return true;    }    return false; }

use can use intersect list of common elements. should create iequalitycomparer, since want identify elements id.

example:

class program {     class x     {         public guid id { get; set; }         public string name { get; set; }         public string description { get; set; }     }      class xequalitycomparer : iequalitycomparer<x>     {         //note: maybe add null check in these methods         public bool equals(x x, x y) { return x.id.equals(y.id); }         public int gethashcode(x obj) { return obj.id.gethashcode(); }     }      static void main(string[] args)     {         var instanceone = new list<x>() {              new x() { id = guid.newguid() },              new x() { id = guid.parse("ef42ee32-1b9e-493c-9d39-4610e0fb29d0") }          };         var instancetwo = new list<x>() {              new x() { id = guid.newguid() },              new x() { id = guid.parse("ef42ee32-1b9e-493c-9d39-4610e0fb29d0") }          };          var common = instanceone.intersect(instancetwo, new xequalitycomparer());     } }

Comments

Post a Comment

Popular posts from this blog

django - How can I change user group without delete record -

-
on website user have 1 group. , user can change group. it's made user.groups.clear() and user.groups.add(new_group) but it's not efficient, because there 2 sql query: delete, insert. how can change group update query? user , group related each other using manytomanyfield . means intersection table exists relating both entities, , if don't specify model map (using through attribute) django creates 1 you. looking @ sources django.contrib.auth.models see that's case. fortunatly, can access intermediary model using through attribute of manager (in case, user.groups.through ). can use regular model. example: >>> alice = user.objects.create_user('alice', 'alice@example.com', 'alicepw') >>> employee = group.objects.create(name='employee') >>> manager = group.objects.create(name='manager') >>> alice.groups.add(employee) >>> alice.groups.all() [<group: employee...
Read more

java - Need to add SOAP security token -

-
i need set custom soap header attribute on jax-ws generated webservice client. case webservice calls must go through proxy server requiring specific token (recieved web request header) present in soap request header. e.g.: 1 carserviceservice service = null; 2 service = new carserviceservice(new url(url), new qname(qname); 3 carserviceendpoint port = service.getcarserviceport(); it seems in line 3 wsdl retrieved , call fails due missing security token. 1 point direction on how done? a detailed example has been mentioned here: creating , deploying jax-ws web service on tomcat 6 this article shows how create , use security token .
Read more

java - EclipseLink JPA Object is not a known entity type -

-
i have strange problem eclipselink , object want persist. have 1 object (keypointlistimpl) stores object keypointimpl in list. persisting keypointimpl objects works great if try persist keypointlistimpl object java.lang.illegalargumentexception says object keypointimpl isn't known entity type. here keypointimpl code: @entity @table(name="keypoints") public class keypointimpl implements keypoint { @id @generatedvalue(strategy = generationtype.identity) private int id; @enumerated(enumtype.string) private detectortype keypointtype; private float x; private float y; private float size; private float angle; private float response; private int octave; private int classid; ... } here keypointlistimpl code: @entity @table(name="keypointlists") public class keypointlistimpl implements keypointlist { @id @generatedvalue(strategy = generationtype.identity) private int id; @onetoone(cascade={ca...
Read more