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Search found 845 results on 34 pages for 'tricky'.

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  • Access to an "upper" instance of a class from another instance of a different class

    - by BorrajaX
    Hello everyone! I have a tricky question and probably what I want to do is not even possible but... who knows... Python seems very flexible and powerful... I'd like to know if there's a way to access to the class (or its fields) where an object is instanciated. Let's say I have: def Class1: def __init__(self): self.title = "randomTitle" self.anotherField = float() self.class2Field = Class2() and the class whose type will be the class2Field: def Class2: def __init__(self): self.field1 = "" self.field2 = "" # . . . # I'd like to know if there's a way to access the instance of Class1 from the instance of Class2 that is declared in Class1 (meaning, accessing the fields of Class1 from the variable self.class2Field in that Class1 instance) I know I can always change the init in Class2 to accept a Class1 parameter, but I'd like to know if there's another way of "climbing" through the class hierachy... Thank you very much!

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  • Field contains foreign IDs for different tables

    - by Rich
    I am developing a php/mysql driven facebook game. I am stuck on an element the table design. When a user completes a task I want to trigger any number of events. I was thinking of something like so: tbl_events *event_id - serogate primary ID *task_id - foreign ID of the task just completed *event_type - what type of event e.g is it a facebook stream publish or a message to the user or does it unlock a new element of the game? *event_param - this is where it gets tricky... the event parameter is a problem for two reasons, 1) it will contain different foreign ids... dependent on the event_type and thus it will not be possible to join to x table. Meaning I would have to call two queries. 2) Most events require a single id or text, however some events require multiple parameters - like the facebook stream publish.

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  • What to use to wait on a indeterminate number of tasks?

    - by Scott Chamberlain
    I am still fairly new to parallel computing so I am not too sure which tool to use for the job. I have a System.Threading.Tasks.Task that needs to wait for n number number of tasks to finish before starting. The tricky part is some of its dependencies may start after this task starts (You are guaranteed to never hit 0 dependent tasks until they are all done). Here is kind of what is happening Parent thread creates somewhere between 1 and (NUMBER_OF_CPU_CORES - 1) tasks. Parent thread creates task to be run when all of the worker tasks are finished. Parent thread creates a monitoring thread Monitoring thread may kill a worker task or spawn a new task depending on load. I can figure out everything up to step 4. How do I get the task from step 2 to wait to run until any new worker threads created in step 4 finish?

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  • PHP fetch all Twitter Followers and compare them to friends

    - by ArneRie
    Hi, iam looking for performant way to do the following: User login Fetch all Friends from Twitter Fetch all Followers from Twitter Display all Friends wich aren't Followers The Problem: How to do this in a performant way? An user can have up to 2 Million Friends or Followers. In the moment im Storing both inside an sqllite table an compare them through an loop. When the user comes back the table is cleared and process starts again. This works finde on 100 - 1000 Friends.. but will be tricky with 500000 Friends. I cant cache the lists because they can change every moment.. Does someone knows a good way to handle such big amount of data?

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  • Attention all SQL gods! Query help needed.

    - by gurun8
    I need a little help putting together a SQL query that will give me the following resultsets: and The data model looks like this: The tricky part for me is that the columns to the right of the "Product" in the resultset are really columns in the database but rather key/value pairs spanned across the data model. Table data is as follows: My apologies in advance for the image heavy question and the image quality. This just seemed like the easiest way to convey the information. It'll probably take someone less time to write the query statement to achieve the results. By the way, the "product_option" table image is truncated but it illustrated the general idea of the data structure. The MySQL server version is 5.1.45.

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  • super(type,subclass) in simple singleton implementation

    - by Tianchen Wu
    when I was implementing naive singleton in python, I came up with a problem with super key word. As usual the behavior of super is always tricky and buggy, hope someone can shed light on it. Thanks :) The problem is that: class Singleton(object): def __new__(cls,*args,**kw): if not hasattr(cls,'_instance'): #create a instance of type cls, origin=super(Singleton,Singleton).__new__(cls,*args,**kw) cls._instance=origin return cls._instance class B(Singleton): def __init__(self,b): self.b=b It actually works, but I am wondering Will it be better if I change line 5 to the below, like in most of the books? origin=super(Singleton,cls).__new__(cls,*args,**ks) what's the difference to make?

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  • Get top 'n' records by report_id

    - by Skudd
    I have a simple view in my MSSQL database. It consists of the following fields: report_id INT ym VARCHAR -- YYYY-MM keyword VARCHAR(MAX) visits INT I can easily get the top 10 keyword hits with the following query: SELECT TOP 10 * FROM top_keywords WHERE ym BETWEEN '2010-05' AND '2010-05' ORDER BY visits DESC Now where it gets tricky is where I have to get the top 10 records for each report_id in the given date range (ym BETWEEN @start_date AND @end_date). How would I go about getting the top 10 for each report_id? I've stumbled across suggestions involving the use of ROW_NUMBER() and RANK(), but have been vastly unsuccessful in their implementation.

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  • Merging and splitting overlapping rectangles to produce non-overlapping ones

    - by uj
    I am looking for an algorithm as follows: Given a set of possibly overlapping rectangles (All of which are "not rotated", can be uniformly represented as (left,top,right,bottom) tuplets, etc...), it returns a minimal set of (non-rotated) non-overlapping rectangles, that occupy the same area. It seems simple enough at first glance, but prooves to be tricky (at least to be done efficiently). Are there some known methods for this/ideas/pointers? Methods for not necessarily minimal, but heuristicly small, sets, are interesting as well, so are methods that produce any valid output set at all.

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  • How to merge arrays with same key and different value in PHP?

    - by Martin
    Hi guys, I have arrays similarly to these: 0 => Array ( [0] => Finance / Shopping / Food, [1] => 47 ) 1 => Array ( [0] => Finance / Shopping / Food, [1] => 25 ) 2 => Array ( [0] => Finance / Shopping / Electronic, [1] => 190 ) I need to create one array with [0] as a key and [1] as value. The tricky part is that if the [0] is same it add [1] to existing value. So the result I want is: array ([Finance / Shopping / Food]=> 72, [Finance / Shopping / Electronic] => 190); thanks

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  • Maintaining Logging and/or stdout/stderr in Python Daemon

    - by dave mankoff
    Every recipe that I've found for creating a daemon process in Python involves forking twice (for Unix) and then closing all open file descriptors. (See http://www.jejik.com/articles/2007/02/a_simple_unix_linux_daemon_in_python/ for an example). This is all simple enough but I seem to have an issue. On the production machine that I am setting up, my daemon is aborting - silently since all open file descriptors were closed. I am having a tricky time debugging the issue currently and am wondering what the proper way to catch and log these errors are. What is the right way to setup logging such that it continues to work after daemonizing? Do I just call logging.basicConfig() a second time after daemonizing? What's the right way to capture stdout and stderr? I am fuzzy on the details of why all the files are closed. Ideally, my main code could just call daemon_start(pid_file) and logging would continue to work.

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  • Java generic Interface performance

    - by halfwarp
    Simple question, but tricky answer I guess. Does using Generic Interfaces hurts performance? Example: public interface Stuff<T> { void hello(T var); } vs public interface Stuff { void hello(Integer var); <---- Integer used just as an example } My first thought is that it doesn't. Generics are just part of the language and the compiler will optimize it as though there were no generics (at least in this particular case of generic interfaces). Is this correct?

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  • Saving substrings using Regular Expressions

    - by user362971
    I'm new to regular expressions in Java (or any language, for that matter) and I'm wanting to do a find using them. The tricky part that I don't understand how to do is replace something inside the string that matches. For example, if the line I'm looking for is Person item6 [can {item thing [wrap]}] I'm able to write a regex that finds that line, but finding what the word "thing" is (as it may differ among different lines) is my problem. I may want to either replace that word with something else or save it in a variable for later. Is there any easy way to do this using Java's regex engine?

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  • Is there a way to check if a host is up?

    - by Rob
    I'm trying to do this in PHP. I need to check if a specified host is "up" I thought of pinging the specified host (though I'm not sure how I would, since that would require root. --help here?) I also though of using fsockopen() to try to connect on a specified port, but that would fail too, if the host wasn't listening for connections on that port. Additionally, some hosts block ping requests, so how might I get around this? This part isn't a necessity, though, so don't worry about this too much. I realize this one might get tricky.

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  • How to deal with the Hibernate hql multi-join query result in an Object-Oriented Way?

    - by EugeneP
    How to deal with the Hibernate hql multi-join query result in an Object-Oriented Way? As I see it returns a list of Objects. yes, it is tricky and only you who write the query know what should the query return (what objects). But are there ways to simplify things, so that it returned specific objects with no need in casting Object to a specific class according to its position in the query ? Maybe Spring can simplify things here? It has the similar functionality for JDBC, but I don't see if it can help in a similar way with Hibernate.

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  • Rails: How to have dynamic association

    - by Aaron Dufall
    I'll use an example to explain what behaviour I would like to achieve. If you had a project management app and you added a task, but not all the contributors are users of the app. So when you adding contributors to the task you can enter a user name or email address. Here is the part that I'm finding a little tricky. The task model has many contributors which are linked through the user model, but from this point on I want to achieve 2 things. Store the non members email(this would obviously be quite simple) If that email address was to create an account it would then link that user to the task and remove the temporally saved email. This way, when that user creates an account all the related tasks will already be associated with their email. Is this something that i could achieve with a polymorphic association? or is there something else I should be looking at?

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  • jQuery selector depending on children

    - by wiradikusuma
    Hi guys, I have an HTML form consisting of some text-inputs. I'm using jqTransform to prettify them. Now I want to add two buttons that will add and remove text-input dynamically. Adding is easy: $('#container').append(''); $('input[name=foo]:last-child').jqTransInputText(); But removing is tricky: $('WHAT-TO-SELECT').remove(); I can't do "input[name=foo]:last-child" since it's already wrapped (some divs) by jqTransform. To put this question in another way: How do I select based on "who has child of type input with 'foo' as its name"?

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  • Minimizing calls to database in rails

    - by ming yeow
    Hi guys, i am familiar with memcached and eager loading, but neither seems to solve the problem i am facing. My main performance lag comes from hundreds of data retrieval calls from the database. The tricky thing is that I do not know which set of users i need to retrieve until i have several steps of computation. I can refactor my code, but i was wondering how you experts handle this situation? I think it should be a fairly common situation def newsfeed - find out which users i need - retrieve those users via DB - find out which events happened for these users - for each of those events - retrieve new set of users - find out which groups are relevant - for each of those groups - retrieve new set of users - etc, etc end

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  • Is it possible to make an online registration process for a course in Google Docs with a cap on registrations?

    - by user61551
    I am trying to build an online registration form for an institute I intern at that is running a training programme with multiple courses and hundreds of applicants. I've done registration forms with Google Docs Forms before, but the tricky spot this time round is that I'm trying to put a registration cap on each of the courses. Every person needs to register for one course in every timeslot, and there are seven or so timeslots. However, as seating space in every venue is limited, we would like to cap registrations per course (venue) to 200 per course, after which either a) the applicant will be informed that they need to register for another course in that timeslot if they apply to a full course, or b) ideal case scenario, the option will be greyed out. Is this possible using Google Docs Forms at all? If not, is there a free alternative that might do the job properly?

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  • Amazon SimpleDB - Is there a way to list all Attributes in a Domain?

    - by beer-drinker
    Hi, I'm using C# and the AWSSDK library form Amazon to test a few things in SimpleDB. All going well so far. However, I am trying to come up with a neat way of retrieving all Attributes that are applicable to a Domain. This is proving to be tricky without having to retrieve an Item, and obviously I can get the list of attributes then. But what if I have 100,000 Items in a Domain. Let's say the first 70,000 Items in a "Person" Domain have: FirstName, LastName, Address And then I hit a Item that has FirstName, LastName, Address, Phone And then I hit another Item around the 80,000 mark which has: FirstName, LastName, Email, Phone In the above example, for the Person Domain, how would I get a list that contains: FirstName, LastName, Address, Email, Phone ...without performing a ridiculous number of select statements? Many thanks!

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  • How do customize the g:sortableColumn?

    - by kakaotalk
    Well, I have one column in my list that I need to customize, the thing is grails' own g:sortable doesn't work. For instance, my first column shows employee ids, then my second column, shows the employees full name where full name is a combination of first name and last name. I got it to work, sorting and all, but when I try to place it in a table with g:sortable, the g:sortable just wouldn't work. I'm thinking about passing params around but it's a bit tricky. Any suggestions? I've looked around the internet, and seems like nothing. :\

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  • Customizing Document library web part

    - by Sushant
    Hi, I am developing a website in Sharepoint 2007. I came across a bit tricky problem. I have a document library web part in a web part page. I am using the summary toolbar view. I dont want users to add new documents on first screeen where it shows folders. I want them to open the folders and add documents there. I cannot do a No toolbar view because it will remove the link from every subsequent page. Has anyone implemented something like this. Please help.

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  • How do you pass an enum by reference?

    - by Darkenor
    I have an enum with four keys I'm taking as input for an interface program and I'd like to pass the enum by value to the interface function, which has become quite long. The enum is like this: enum MYKEYS { W, S, O, L }; There's also a boolean array that I have to pass by reference, which is also a little tricky. bool key[4] = { false, false, false, false }; Does anyone know the proper syntax to pass both of these as reference in a function, similar to: function(int & anintreference);

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  • How can I define a one-time event so that new handlers fire (once) even after the event has already occurred?

    - by harpo
    You know how this $(function() { ... }); will fire whether or not the "document ready" event has already occurred? I want to define an event like that. That event is a special case in jQuery. I'm wondering if a custom event can behave in the same way, using only the standard event mechanisms. Ideally, I'd like to be able to define handlers in the "normal" way: $(document).on("init.mything", function() { ... }); This works now if the above runs before init.mything is triggered. But if it doesn't, then the handler never runs. What makes this tricky is, I don't want to assume anything except that jQuery has loaded. Any ideas?

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  • mySQL .NET API - Delete all data from table

    - by keynesiancross
    Hi all, I'm trying to figure out if there is an easy way to delete all the data in a table using the mySQL .NET API. The only slightly more tricky part to this is that in the C# code, the business logic can be run in both cases where there is, or isn't, data in teh table. So in some regards I almost need an If statement... Currently I am using the following code, but it doesn't seem to ever delete data... string deleteSQL = "DELETE FROM `data`.`currentData`"; MySqlCommand cmd2 = new MySqlCommand(deleteSQL, conn); Any thoughts would be much appreciated! Cheers

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  • Java, UnmarshallingException caused by XML attribute with special chars: ;ìè+òàù-<^èç°§_>!£$%&/()=?~

    - by segolas
    Hi, my xml file has a tag with an attribute "containsValue" which contains the "special" characters you can see in the subject: <original_msg_body id="msgBodySpecialCharsRule" containsValue=";ìè+òàù-<^èç°§_>!£$%&/()=?~`'#;" /> in my xml schema the attribute has xs:string: <xs:attribute name="containsValue" type="xs:string" /> I use this value inside a Java software which check if this value is contained inside another String. but I always obtain this Exception: javax.xml.bind.UnmarshalException - with linked exception: [org.xml.sax.SAXParseException: The value of attribute "containsValue" associated with an element type "original_msg_body" must not contain the '<' character.] How can I solve it? I've tried changing the attribute type to xs:NMTOKEN, ut I get the same exception. Is there any other type? I think I could change the characters encoding, for example using the HTML representation, like <, but than could be tricky for the string comparison...

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