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Search found 765 results on 31 pages for 'discriminated union'.

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• good methods for boolean operations on overlapping polygons

  - by BenjaminGolder

  What is the best open source library for performing boolean operations (union, intersect, subtract) on shapefiles? What do you like to use? OGR looks like it probably has this capability, though I'm having trouble finding the particular commands in their documentation. Shapely definitely does this, and is easy to understand. PostGIS appears to also have some commands for this. But there must be more, and I'm having trouble finding them. I don't have much experience with any of the, and would appreciate any opinions on these or other libraries. Thanks!

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• Theory of Computation - Showing that a language is regular..

  - by Tony

  I'm reviewing some notes for my course on Theory of Computation and I'm a little bit stuck on showing the following statement and I was hoping somebody could help me out with an explanation :) Let A be a regular language. The language B = {ab | a exists in A and b does not exist in A*} Why is B a regular language? Some points are obvious to me. If b is simply a constant string, this is trivial. Since we know a is in A and b is a string, regular languages are closed under union, so unioning the language that accepts these two strings is obviously regular. I'm not sure that b is constant, however. Maybe it is, and if so, then this isn't really an issue. I'm having a hard time making sense of it. Thanks!

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• Building a clip area in a UIView from path objects in its subviews

  - by hkatz

  I'm trying to produce a clipping area in a UIView that's generated from path objects in its subviews. For example, I might have one subview containing a square and another containing a circle. I want to be able to produce a clip in the parent superview that's the union of both these shapes. Can someone explain how to do this? About all I've been able to figure out so far is that: 1 - the superview's drawRect: method is called before its subviews' drawRects are, and 2 - the ContextRef that's accessible in all three instances is the same. Other than that I'm stumped. Thanks, Howard

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• Generating a list of Strings in Obj C

  - by eco_bach

  Hi It seems that Objective C jumps thru hoops to make seemingly simple tasks extremely difficult. I simply need to create a sequence of strings, image1.jpg, image2.jpg, etc etc ie in a loop var imgString:String='image'+i+'.jpg; I assume a best practice is to use a NSMutableString with appendString method? What am I doing wrong?? NSMutableString *imgString; for(int i=1;i<=NUMIMAGES;i++){ imgString.appendString(@"image"+i+@".jpg"); } I get the following error error: request for member 'appendString' in something not a structure or union

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• Set Theory and .NET

  - by MasterMax1313

  Recently I came across a situation where set theory and set math fit what I was doing to the letter (granted there was an easier way to accomplish what I needed - i.e. LINQ - but I didn't think of that at the time). However I didn't know of any generic set libraries. Granted IEnumerables provide some set operations (Union, etc.), but nothing like Intersection or set comparison. Can anyone point out something that fits here? Something that implements set math using a generic type?

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• ExecuteStoreQuery passing parameter to StoreProcedure

  - by KDM

  Could someone help with passing a parameter object into my ExecuteStoreQuery. Im executing this from my Entities db and then creating my procedure on the fly is this possible and is my SQL correct. i need to pass a Id paramater value into my sql statement var node = db.ExecuteStoreQuery<Node>(@" @Id int // not sure about this declaration for paramater with c as ( select Id, Name, ParentId,[0] as level from Department d union all select d.Id, d.Name, d.ParentId, [level] + 1 from Department d join c on d.ParentId = c.Id) select * from c where c.Id = @Id" "Departments", System.Data.Objects.MergeOption.NoTracking, new object{ Id: department.Id} // <--paramater object not working);

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• iBatis get executed sql

  - by qaxi

  Hi all. Is there any way where I can get the executed query of iBatis? I want to reuse the query for an UNION query. For example: <sqlMap namespace="userSQLMap"> <select id="getUser" resultClass="UserPackage.User"> SELECT username, password FROM table WHERE id=#value# </select> </sqlMap> And when I execute the query through int id = 1 List<User> userList = queryDAO.executeForObjectList("userSQLMap.getUser",id) I want to get SELECT username, password FROM table WHERE id=1 Is there any way I could get the query? Thanks.

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• Error: CLLocationManager headingAvailable

  - by Bubu4711

  I have the following code: In my .h-Header-File: #import <UIKit/UIKit.h> #import <CoreLocation/CoreLocation.h> @interface Compass : UIViewController <CLLocationManagerDelegate> { [...] CLLocationManager *locationManager; } [...] @property(nonatomic, retain) CLLocationManager *locationManager; @end And my .m-File: #import "[FILENAME].h" [...] @synthesize locationManager; - (void)viewDidLoad { [super viewDidLoad]; self.locationManager = [[[CLLocationManager alloc] init] autorelease]; if(locationManager.headingAvailable == NO) { [...] } [...] } And I get the following error Message for "locationManager.headingAvailable": error:request for member 'headingAvailable' in something not a structure or union I've added the CoreLocation framework to my app... Who can help me?

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• When and how should custom hierarchies be used in clojure?

  - by Rob Lachlan

  Clojure's system for creating an ad hoc hierarchy of keywords is familiar to most people who have spent a bit of time with the language. For example, most demos and presentations of the language include examples such as (derive ::child ::parent) and they go on to show how this can be used for multi-method dispatch. In all of the slides and presentations that I've seen, they use the global hierarchy. But it is possible to keyword relationships in custom hierarchies. Some questions, therefore: Are there any guidelines on when this is useful or necessary? Are there any functions for manipulating hierarchies? Merging is particularly useful, so I do this: (defn merge-h [& hierarchies] (apply merge-with (cons #(merge-with clojure.set/union %1 %2) hierarchies)) But I was wondering if such functions already exist somewhere.

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• starting flash game development

  - by wefwgeweg

  where to begin ? i want to create multiplayer flash games using Union (any experience?) but which IDE and prerequisites do i need to begin ? also, what does Flex mean ? thank you. p.s. what is the best way to purchase Game assets ? ex) 2d sprites...i've given up trying to design my own. i need to outsource (any dedicated place for finding offshore artists?) or buy some package.

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• C++/CLI .ToString() returning error

  - by George Johnston

  I am a beginner to C++/CLI as I come from a C# background. I am currently writing a wrapper for some native C++ code. I have the following methods: void AddToBlockList(System::String^ address) { char* cAddress = (char*)(void*)Marshal::StringToHGlobalAnsi(address); _packetFilter->AddToBlockList(cAddress); } void AddToBlockList(IPAddress^ address) { char* cAddress = (char*)(void*)Marshal::StringToHGlobalAnsi(address.ToString()); _packetFilter->AddToBlockList(cAddress); } ...The first method works fine and converts my string into the character array. However, the second function with the IPAddress object as the signiture gives me the following error: error C2228: left of '.ToString' must have class/struct/union ...When I type ? address.ToString() ...in the command window, the IP Address prints. Not sure where I'm going wrong. Any ideas?

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• Assigning to struct in different class

  - by 4thSpace

  I have a struct in ClassA and want to assign it to the same struct in ClassB (the two structs are the same with different names). ClassA and ClassB are view controllers. Basically, I need to pass this struct to another class. However, structs don't seem to be exposed as members, which means I can't access them. Here is ClassA's struct declared in its header file: typedef struct { NSString *startDate; NSString *endDate; NSString *classId; } selectedItemsClassAStruct; selectedItemsClassAStruct selectedItemsClassA; and the same for ClassB (just with ClassA text replaced) It doesn't appear in code hints for ClassB. I see this error if I try to access it: request for member 'selectedItemsClassBStruct' in something not a structure or union How should it be done?

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• C# -Interview Question Anonymous Type

  - by Amutha

  Recently i was asked to prove the power of C# 3.0 in a single line( might be tricky) i wrote new int[] { 1, 2, 3 }.Union(new int[]{10,23,45}). ToList().ForEach(x => Console.WriteLine(x)); and explained you can have (i) anonymous array (ii) extension method (iii)lambda and closure all in a single line.I got spot offer. But..... The interviewer asked me how will you convert an anonymous type into know type :( I am 100% sure ,we can not do that.The interviewer replied there is 200% chance to do that if you have a small work around.I was clueless. As usual,I am waiting for your valuable reply(Is it possible?).

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• Insert rows into MySQL table while changing one value

  - by Jonathan

  Hey all- I have a MySQL table that defines values for a specific customer type. | CustomerType | Key Field 1 | Key Field 2 | Value | Each customer type has 10 values associated with it (based on the other two key fields). I am creating a new customer type (TypeB) that is exactly the same as another customer type (TypeA). I want to insert "TypeB" as the CustomerType but then just copy the values from TypeA's rows for the other three fields. Is there an SQL insert statement to make this happen? Somthing like: insert into customers(customer_type, key1, key2, value) values "TypeB" union select key1, key2, value from customers where customer_type = "TypeA" Thanks- Jonathan

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• 'whatever' has no declared type

  - by mihirpmehta

  i am developing parser using bison...in my grammar i am getting this error Here is a code extern NodePtr CreateNode(NodeType, ...); extern NodePtr ReplaceNode(NodeType, NodePtr); extern NodePtr MergeSubTrees(NodeType, ...); ................... NodePtr rootNodePtr = NULL; /* pointer to the root of the parse tree */ NodePtr nodePtr = NULL; /* pointer to an error node */ ........................... NodePtr mainMethodDecNodePtr = NULL; ................ /* YYSTYPE */ %union { NodePtr nodePtr; } i am getting this error whenever i use like $$.nodePtr or $1.nodePtr ... I am getting Parser.y:1302.32-33: $1 of `Expressi on' has no declared type

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• LINQ and set difference

  - by Pierre

  I have two collections a and b. I would like to compute the set of items in either a or b, but not in both (a logical exclusive or). With LINQ, I can come up with this: IEnumerable<T> Delta<T>(IEnumerable<T> a, IEnumerable<T> b) { return a.Except (b).Union (b.Except (a)); } I wonder if there are other more efficient or more compact ways of producing the difference between the two collections.

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• static arrays defined with unspecified size, empty brackets?

  - by ahmadabdolkader

  For the C++ code fragment below: class Foo { int a[]; // no error }; int a[]; // error: storage size of 'a' isn't known void bar() { int a[]; // error: storage size of 'a' isn't known } why isn't the member variable causing an error too? and what is the meaning of this member variable? I'm using gcc version 3.4.5 (mingw-vista special) through CodeBlocks 8.02. On Visual Studio Express 2008 - Microsoft(R) C/C++ Optimizing Compiler 15.00.30729.01 for 80x86, I got the following messages: class Foo { int a[]; // warning C4200: nonstandard extension used : zero-sized array in struct/union - Cannot generate copy-ctor or copy-assignment operator when UDT contains a zero-sized array }; int a[]; void bar() { int a[]; // error C2133: 'a' : unknown size } Now, this needs some explaination too.

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• SQL syntax Newbie student

  - by sammysmall

  Describe the output of the following SQL query: select custId, name from customer where region = "New York" UNION select cust.custId, cust.name from customer cust where cust.custId IN (select cust_order.custId from customer_order cust_order, company_employee comp_emp where cust_order.salesEmpId = comp_emp.empId AND comp_emp.name = 'DANIEL'); My question is: at line from customer cust is cust referring to a column in the customer table... This is a homework question I have identified the components leading up to this line and I think that cust is a column in the customer table... I am not asking for an overall solution just a bit of encouragement if I am on the right track...

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• Conditional Join - join 1 tables 2 ways

  - by Jon H

  I have a set of (not very well normalised or relational) tables named PLAN, GROUP, PRODUCT CLIENT Most have linkage i.e. PLAN - CLIENT on clno GROUP to PRODUCT on PRODCD However, the linkage between PLAN and GROUP is tricky. A plan has 2 field of interest GRPNO and PRODCD. What I want to do is if GRPNO != 0 then join GROUP on GRPNO. However if GRPNO = 0 then I want to join GROUP on PRODCD. The frustrating thing is that the fileds I want to return in my queries are the same across the board I just need to be able to vary the join, or join the same table twice. The best I can come up with is 2 queries and merge them using datasets, or possibly using a union. Is there a nifty way to do this in one select? I should point out I am access Foxpro over ODBC to do this. Thank you!

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• warning in Eclipse

  - by lego69

  hello, I have some problems with Eclipse, I have structure struct Account{ const char* strLastName; //Client's last name const char* strFirstName; //Client's first name int nID; //Client's ID number int nLines; //Number of lines related to account double lastBill; //Client's last bill for all lines List linesDataBase; }; And I can't compile my code eclipse gives me an errors: Syntax error before List no semicolon at end of struct or union ISO does not allow extra ";" outside a function I have no idea how to change it, thanks in advance for any help

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• SQL latest/top items in category

  - by drozzy

  What is a scalable way to select latest 10 items from each category. I have a schema list this: item category updated so I want to select 10 last update items from each category. The current solution I can come up with is to query for categories first and then issue some sort of union query: query = none for cat in categories: query += select top 10 from table where category=cat order by updated I am not sure how efficient this will be for bigger databases (1 million rows). If there is a way to do this in one go - that would be nice. Any help appreciated.

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• iPhone Setting ViewController nested in NSMutableArray

  - by Peter George

  Hello I'm trying to set attributes for a viewcontroller nested inside a NSMutableArray, for example I have 3 ViewController inside this array: FirstViewController *firstViewController = [FirstViewController alloc]; SecondViewController *secondViewController = [SecondViewController alloc]; ThirdViewController *thirdViewController = [ThirdViewController alloc]; NSMutableArray *viewControllerClasses = [[NSMutableArray alloc] initWithObjects: firstViewController, secondViewController, thirdViewController, nil]; for (int x=0; x<[viewControllerClasses count]; x++) { // as an example to set managedObjectContext I otherwise would set firstViewController.managedObjectContext = context; [viewControllerClasses objectAtIndex:x].managedObjectContext = context; } But this results in an error: Request for member "managedObjectContext" in something not a structure or union. Shouldn't be "firstViewController" be the same as [viewControllerClasses objectAtIndex:0]?

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• Ordering recursive result set in SQL Server

  - by Ben

  I am having extreme difficulty constructing a query which returns an XML style hierarchy. We have a database table which contains a hierarchy of URLs for our website. The table contains the columns: ID, URL, DisplayName, ParentID, ItemOrder The parent ID forms a recursive relationship between the current item and it's parent. The item should site below it's parent in the hierarchy and it should also be ordered using the item order against items at the same level in the hierarchy. I have managed to get a recursive query working so it drills down the hierarchy sequentially but I cannot order this by the item order as well. My current query is below: WITH Parents AS ( SELECT MenuItemId, URL, ParentItemId, ItemOrder FROM CambsMenu UNION ALL SELECT si.MenuItemId, si.URL, si.ParentItemId, si.ItemOrder FROM CambsMenu si INNER JOIN Parents p ON si.ParentItemId = p.MenuItemId ) SELECT DISTINCT * FROM Parents

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• Create view or SP, only if the DB contains a pattern

  - by Randall Salas

  Hi all: I am working on a script, that needs to be run in many different SQL servers. Some of them, shared the same structure, in other words, they are identical, but the filegroups and the DB names are different. This is because is one per client. Anyway, I would like when running a script, If I chose the wrong DB, it should not be executed. I am trying to mantain a clean DB. here is my example, which only works for dropping a view if exists, but does not work for creating a new one. I also wonder how it would be for creating a stored procedure. Thx a lot. if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[ContentModDate]') and OBJECTPROPERTY(id, N'IsView') = 1) AND CHARINDEX('Content', DB_NAME()) 0 drop view [dbo].[ContentModDate] GO IF (CHARINDEX('Content', DB_NAME()) 0)BEGIN CREATE VIEW [dbo].[Rx_ContentModDate] AS SELECT 'Table1' AS TableName, MAX(ModDate) AS ModDate FROM Tabl1 WHERE ModDate IS NOT NULL UNION SELECT 'Table2', MAX(ModDate) AS ModDate FROM Table2 WHERE ModDate IS NOT NULL END END GO

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• SQL server - climb up in the tree structure

  - by Vytas999

  Hello. I have some sql table, named Object, which saves tree data in fields ObjectID, ParentID, and others. I have implemented recurse procedure, which select everything down by objectID from tree, like this: 1. 1.1. 1.2. 1.2.1. ... Now o need to "Climb up" - by some ObjectID i need to select everything Up, like this: 1.2.1. 1.2. 1. How i can do that? In example, my "down" procedure looks like: ALTER PROCEDURE [dbo].[Object_SelectDownByRoot_Simple] @ObjectID int AS WITH tree (ObjectID, ParentID, ObjectName, ObjectCode) AS ( SELECT ObjectID, ParentID, ObjectName, ObjectCode FROM dbo.[ObjectQ] ofs WHERE( ObjectID = @ObjectID ) UNION ALL SELECT ofs.ObjectID, ofs.ParentID, ofs.ObjectName, ofs.ObjectCode FROM dbo.[ObjectQ] ofs JOIN tree ON tree.ObjectID = ofs.ParentID ) SELECT ObjectID, ParentID, ObjectName, ObjectCode FROM tree

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