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  • How to set a __str__ method for all ctype Structure classes?

    - by Reuben Thomas
    [Since asking this question, I've found: http://www.cs.unc.edu/~gb/blog/2007/02/11/ctypes-tricks/ which gives a good answer.] I just wrote a __str__ method for a ctype-generated Structure class 'foo' thus: def foo_to_str(self): s = [] for i in foo._fields_: s.append('{}: {}'.format(i[0], foo.\_\_getattribute__(self, i[0]))) return '\n'.join(s) foo.\_\_str__ = foo_to_str But this is a fairly natural way to produce a __str__ method for any Structure class. How can I add this method directly to the Structure class, so that all Structure classes generated by ctypes get it? (I am using the h2xml and xml2py scripts to auto-generate ctypes code, and this offers no obvious way to change the names of the classes output, so simply subclassing Structure, Union &c. and adding my __str__ method there would involve post-processing the output of xml2py.)

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  • Alternative to 'where col in (list)' for MySQL

    - by user210481
    Hi I have the following table T: id 1 2 3 4 col a b a c I want to do a select that returns the id,col when group by(col) having count(col)1 One way of doing it is SELECT id,col FROM T WHERE col IN (SELECT col FROM T GROUP BY(col) HAVING COUNT(col)>1); The intern select (from the right) returns 'a' and main one (left) will return 1,a and 3,a The problem is that the where in statement seems to be extremely slow. In my real case, the results from the internal select has many 'col's, something about 70000 and it's taking hours. Right now it's much faster to do the internal select and the main select getting all ids and upcs and do the intersection locally. MySQL should be able to handle this kind of query efficiently. Can I substitute the where in for a join or something faster? Thanks

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  • java socket programming problem

    - by mk.persia
    Hi, what's wrong with my code? sorry about my bad English package sockettest; import java.io.*; import java.net.*; class sevr implements Runnable{ public void run() { ServerSocket sSkt = null; Socket skt = null; BufferedReader br = null; BufferedWriter bw = null; try{ System.out.println("Server: is about to create socket"); sSkt = new ServerSocket(6666); System.out.println("Server: socket created"); } catch(IOException e){ System.out.println("Server: socket creation failure"); } try{ System.out.println("Server: is listening"); skt = sSkt.accept(); System.out.println("Server: Connection Established"); } catch(IOException e){ System.out.println("Server: listening failed"); } try{ System.out.println("Server: creating streams"); br = new BufferedReader(new InputStreamReader(skt.getInputStream())); bw = new BufferedWriter(new OutputStreamWriter(skt.getOutputStream())); System.out.println("Server: stream done"); } catch(IOException e){ System.out.println("Server: stream failed"); } System.out.println("Server: reading the request"); try{ String line = null; while((line =br.readLine()) != null){ System.out.println("Server: client said- "+ line); } } catch(IOException e){ System.out.println("Server: reading failed"); } System.out.println("Server: reading fished"); System.out.println("Server: responding"); try{ bw.write("Hi! I am server!"); } catch(IOException e){ System.out.println("Server: responding failed"); } System.out.println("Server: responding finished"); System.out.println("Server: is finishing"); try { br.close(); bw.close(); skt.close(); sSkt.close(); } catch (IOException e) { System.out.println("Server: finishing failed"); } System.out.println("Server: done"); } } class clnt implements Runnable{ public void run() { Socket skt = null; BufferedReader br = null; BufferedWriter bw = null; try{ System.out.println("Client: about to create socket"); skt = new Socket(InetAddress.getLocalHost(),6666); System.out.println("Client: socket created"); } catch(IOException e){ System.out.println("Client: socket creation failure"); } try{ System.out.println("Client: creating streams"); br = new BufferedReader(new InputStreamReader(skt.getInputStream())); bw = new BufferedWriter(new OutputStreamWriter(skt.getOutputStream())); System.out.println("Client: stream done"); } catch(IOException e){ System.out.println("Client: stream failed"); } System.out.println("Client: requesting"); try{ bw.write("Hi! I am Client!"); } catch(IOException e){ System.out.println("Client: requesting failed"); } System.out.println("Client: requesting finished"); System.out.println("Client: reading the respond"); try{ String line = null; while((line =br.readLine()) != null){ System.out.println("Client: server said- "+ line); } } catch(IOException e){ System.out.println("Client: reading failed"); } System.out.println("Client: reading fished"); System.out.println("Clientrver: is finishing"); try { br.close(); bw.close(); skt.close(); } catch (IOException e) { System.out.println("Client: finishing failed"); } System.out.println("Client: done"); } } public class Main { public static void main(String[] args) { System.out.println("Main started"); Thread sThread = new Thread(new sevr()); Thread cThread = new Thread(new clnt()); sThread.start(); cThread.start(); try { sThread.join(); cThread.join(); } catch (InterruptedException ex) { System.out.println("joining failed"); } System.out.println("Main done"); } } output: Main started Server: is about to create socket Client: about to create socket Client: socket created Client: creating streams Server: socket created Server: is listening Server: Connection Established Server: creating streams Server: stream done Server: reading the request Client: stream done Client: requesting Client: requesting finished Client: reading the respond and it waits here forever!

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  • stop the CSS filter property cascading

    - by Ayoub
    I tried to make box-shadow affect work cross browsers, in order to make ie work I used "filter" property but the effect cascades to the child element (in my case a span) I tried to stop it by using filter : none but it didn't work searched the web but I couldn't find a solution. please help me solve this problem. HTML code : <div id="shadow"> <span>text text</span> </div> CSS code : #shadow{ -moz-box-shadow: 3px 3px 4px #000; -webkit-box-shadow: 3px 3px 4px #000; box-shadow: 3px 3px 4px #000; /* For IE 8 */ -ms-filter: "progid:DXImageTransform.Microsoft.Shadow(Strength=4, Direction=135, Color='#000000')"; /* For IE 5.5 - 7 */ filter: progid:DXImageTransform.Microsoft.Shadow(Strength=4, Direction=135, Color='#000000'); }

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  • Help needed in AdventureWorks in a sql query.

    - by vaibhav
    I was just playing with adventureworks database in sqlserver. I got stuck in a query. I wanted to Select all titles from HumanResources.Employee which are either 'Male' or 'Female' but not both. i.e if title Accountant is Male and Female both I want to leave that title. I need only those titles where Gender is either Male or Female. I have done this till yet. select distinct(title) from humanresources.employee where gender='M' select distinct(title) from humanresources.employee where gender='F' Probably a join between these two queries, would work. But If you have any other solution, please let me know. It is not a homework. :) Thanks in advance.

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  • How to retrieve row count of one-to-many relation while also include original entity?

    - by kaa
    Say I have two entities Foo and Bar where Foo has-many Bar's, class Foo { int ImportantNumber { get; set; } IEnumerable<Bar> Bars { get; set; } } class FooDTO { Foo Foo { get; set; } int BarCount { get; set; } } How can I efficiently sum up the number of Bars per Foo in a DTO using a single query, preferrably only with the Criteria interface. I have tried any number of ways to get the original entity out of a query with ´SetProjection´ but no luck. The current theory is to do something like SELECT Foo.*, BarCounts.counts FROM Foo LEFT JOIN ( SELECT fooId, COUNT(*) as counts FROM Bar GROUP BY fooId ) AS BarCounts ON Foo.id=BarCounts.fooId but with Criterias, and I just can't seem to figure out how.

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  • What grid distributed computing frameworks are currently favoured for trading systems

    - by Rich
    There seems to a quite a few grid computing frameworks out there, but which ones are actually being used to any great extent by the investment banks for purposes of low latency distributing calculation? I'd be interested to hear answers covering both windows,Linux and cross platform. Also, what RPC mechanisms seem to be favoured most? I've heard that for reason of low latency and speed, the calculations themselves are quite often written in C++/C as calculations running on VMs are several orders of magnitude slower than native code. Does this seem to be a common scenario in practice? e.g distributed .NET grid framework running calculations written in native c++/c?

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  • How to automaticly add a page number to all internal links on the HTML page?

    - by Tomasz
    In print mode, I would like to render such a links: <a href="#targetPage">link</a> like this: <a href="#targetPage">link (page 11)</a> (suppose the target page is on 11. page in print preview). It is possible to add page number using counters to the page footer with plain CSS, but could I use this in more "the way I want it" way? The solution doesn't need to be cross-browser (FF/Chrome is enough), any CSS/Javascript tricks are allowed...

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  • dataset using where condition from another query

    - by refer
    here's my code. I have a dataset that has its values and then i run an independent query which uses the same tables as dataset. now when i run the dataset, i want it to get a where condition on the query result. here's the code - sql = "SELECT ID, name FROM books WITH(NOLOCK) WHERE id =" & Session("ID") ds = FillDataset(sql) Sql1 = "SELECT n.id as id,a.name as title FROM books n WITH(NOLOCK)" & _ "LEFT JOIN new_books a WITH(NOLOCK) ON a.id = n.book_id " rd = ExecuteReader(SqlCnn, SqlStr) Now after this i make an htmltable and all the cells are loaded with the data from datareader(rd). but 1 dropdown is loaded from the dataset. i want that dropdown to have the selectedvalue which is the value from the datareader(rd). how can i do that?

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  • Is it hard problem?

    - by Lukasz Lew
    I can't solve it: You are given 8 integers: A, B, C representing a line on a plane with equation A*x + B*y = C a, b, c representing another line x, y representing a point on a plane The two lines are not parallel therefore divide plane into 4 pieces. Point (x, y) lies inside of one these pieces. Problem: Write a fast algorithm that will find a point with integer coordinates in the same piece as (x,y) that is closest to the cross point of the two given lines. Note: This is not a homework, this is old Euler-type task that I have absolutely no idea how to approach.

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  • Reducing a normalized table to one value

    - by Dio
    Hello, I'm sure this has been asked but I'm not quite sure how to properly search for this question, my apologies. I have two tables, Foo and Bar. For has one row per Food, bar has many rows per food matching descriptors. Foo name id Apple 1 Orange 2 Bar id description 1 Tasty 1 Ripe 2 Sweet etc (sorry for the somewhat contrived example). I'm trying to return a query where if, for each row in Foo, Bar contains a descriptor in ('Tasty', 'Juicy') return true ex: Output Apple True Orange False I had been solving this somewhat trivially with a case when I only had one item to match select Foo.name, case bar.description when 'Tasty' then True else 'False' end from Foo left join Bar on foo.id = bar.id where bar.description = 'Tasty' But with multiple items, I keep ending up with extra rows: Output Apple True Apple False etc etc Can someone point me in the right direction on how to think about this problem or what I should be doing? Thank you.

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  • Denormalize for Simplicity: Ungood idea?

    - by yar
    After reading this question, I've learned that denormalization is not a solution for simplicity. What about this case? I have news-articles which have a list of sites-article-will-be-published-to. The latter can be expressed in normalized fashion either by table and a many-to-many relationship (via a cross-table, I think). But the simple solution is to just throw a bunch of booleans for the sites-article-will-be-published-to. Assuming the sites are: small in number will not change over time have no fields themselves, except a name Is this still a terrible idea? The many-to-many relationship seems somewhat cumbersome, but I've done it before in cases like this (and it seemed cumbersome). Note: I'm doing this in Rails, where it's not that painful.

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  • Django: How do I get logging working?

    - by swisstony
    I've added the following to my settings.py file: import logging ... logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(levelname)s %(message)s', filename=os.path.join(rootdir, 'django.log'), filemode='a+') And in views.py, I've added: import logging log = logging.getLogger(__name__) ... log.info("testing 123!") Unfortunately, no log file is being created. Any ideas what I am doing wrong? And also is their a better method I should be using for logging? I am doing this on Webfaction.

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  • Project Euler #163 understanding

    - by Paul
    I spent quite a long time searching for a solution to this problem. I drew tons of cross-hatched triangles, counted the triangles in simple cases, and searched for some sort of pattern. Unfortunately, I hit the wall. I'm pretty sure my programming/math skills did not meet the prereq for this problem. So I found a solution online in order to gain access to the forums. I didn't understand most of the methods at all, and some just seemed too complicated. Can anyone give me an understanding of this problem? One of the methods, found here: http://www.math.uni-bielefeld.de/~sillke/SEQUENCES/grid-triangles (Problem C) allowed for a single function to be used. How did they come up with that solution? At this point, I'd really just like to understand some of the concepts behind this interesting problem. I know looking up the solution was not part of the Euler spirit, but I'm fairly sure I would not have solved this problem anyhow.

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  • To capture Tv tuner/webcam output

    - by mawia
    Hi! all, We are developting a tool for live video streaming in which we want to broadcast the output of tv tuner on a network.Our project is at it's nascent stage.Our main concern at this moment is to how to capture the output of a tv tuner card.Plz guide us regarding this or provide a pointer where I can detail about the topic. All help will be highly appreciated. Thanks Mawia ps:project is for cross-platform but at the moment even if you tell me of any one platform it will be enough!

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  • Why does derivative trading position always require C++ knowledge?

    - by Jeffrey
    I’ve never worked in trading environment before and I was curious to see that few of the trading houses seem to use C# but most of them do heavily rely on C++. Why is it? Is it because C++ is better performance wise? Is it because of legacy code base? Is it because cross platform issue? What about dynamic languages (ruby, python)? Are they too slow for this kind of work in terms of performance? Updated: If realibility and performance are important would "Erlang" be the "next big thing" in trading platform?

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  • How can I pull data from a SQL Database that spans an academic year?

    - by Eric Reynolds
    Basically, I want to pull data from August to May for a given set of dates. Using the between operator works as long as I do not cross the year marker (i.e. BETWEEN 8 AND 12 works -- BETWEEN 8 AND 5 does not). Is there any way to pull this data? Here is the SQL Query I wrote: SELECT count(*), MONTH(DateTime) FROM Downloads WHERE YEAR(DateTime) BETWEEN 2009 AND 2010 AND MONTH(DateTime) BETWEEN 8 AND 5 GROUP BY MONTH(DateTime) ORDER BY MONTH(DateTime)" Any help is appreciated. Thanks, Eric R.

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  • Combining 2 Linq queries into 1

    - by Mike Fielden
    Given the following information, how can I combine these 2 linq queries into 1. Having a bit of trouble with the join statement. 'projectDetails' is just a list of ProjectDetails ProjectDetails (1 to many) PCardAuthorizations ProjectDetails (1 to many) ExpenditureDetails Notice I am grouping by the same information and selecting the same type of information var pCardAccount = from c in PCardAuthorizations where projectDetails.Contains(c.ProjectDetail) && c.RequestStatusId == 2 group c by new { c.ProjectDetail, c.ProgramFund } into g select new { Key = g.Key, Sum = g.Sum(x => x.Amount) }; var expenditures = from d in ExpenditureDetails where projectDetails.Contains(d.ProjectDetails) && d.Expenditures.ExpenditureTypeEnum == 0 group d by new { d.ProjectDetails, d.ProgramFunds } into g select new { Key = g.Key, Sum = g.Sum(y => y.ExpenditureAmounts.FirstOrDefault(a => a.IsCurrent && !a.RequiresAudit).CommittedMonthlyRecords.ProjectedEac) };

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  • running Hadoop software on office computers (when they are idle)

    - by Shahbaz
    Is there a project which helps setup a Hadoop cluster on office desktops, when they are idle? I'd like to experiment with Hadoop/MR/hbase but don't have acces to 5-10 computers. The computers at work are idle after hours and are connected to each other through a very high speed connection. What's more, data on these computers stays within our network so there is no privacy issue. In order for this to work I need a fairly light weight monitor running on each machine. When the computer has been idle for X hours, it will join the cluster. If the user logs on, it has to drop out of the cluster and return all CPU/memory back. Does something like this exist?

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  • Error(2,7): PLS-00428: an INTO clause is expected in this SELECT statement

    - by omgzor
    I'm trying to create this trigger and getting the following compiler errors: create or replace TRIGGER RESTAR_PLAZAS AFTER INSERT ON PLAN_VUELO BEGIN SELECT F.NRO_VUELO, M.CAPACIDAD, M.CAPACIDAD - COALESCE(( SELECT count(*) FROM PLAN_VUELO P WHERE P.NRO_VUELO = F.NRO_VUELO ), 0) as PLAZAS_DISPONIBLES FROM VUELO F INNER JOIN MODELO M ON M.ID = F.CODIGO_AVION; END RESTAR_PLAZAS; Error(2,7): PL/SQL: SQL Statement ignored Error(8,5): PL/SQL: ORA-00933: SQL command not properly ended Error(8,27): PLS-00103: Encountered the symbol "end-of-file" when expecting one of the following: begin case declare end exception exit for goto if loop mod null pragma raise return select update while with <an identifier> <a double-quoted delimited-identifier> <a bind variable> << close current delete fetch lock insert open rollback savepoint set sql execute commit forall merge pipe Error(2,1): PLS-00428: an INTO clause is expected in this SELECT statement What's wrong with this trigger?

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  • How do I do multiple has_and_belongs_to_many associations between the same two classes?

    - by Ermin
    I have the following setup: class Publication < ActiveRecord::Base has_and_belongs_to_many :authors, :class_name=>'Person', :join_table => 'authors_publications' has_and_belongs_to_many :editors, :class_name=>'Person', :join_table => 'editors_publications' end class Person < ActiveRecord::Base has_and_belongs_to_many :publications end With this setup I can do stuff like Publication.first.authors. But if I want to list all publications in which a person is involved Person.first.publications, an error about a missing join table people_publications it thrown. How could I fix that? Should I maybe switch to separate models for authors and editors? It would however introduce some redundancy to the database, since a person can be an author of one publication and an editor of another.

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  • Rails Association issue with NoMethodError in event_controller

    - by pmanning
    Kinda a noob trying to understand I think I need to define rsvps but not sure what to put... I'm trying to add a Join/Unjoin button to user created Events, similar to a Follow/Unfollow button for Users. NoMethodError in Events#show undefined method `model_name' for NilClass:Class in line #1 _unjoin.html.erb 1: <%= form_for(current_user.rsvps.find_by_joined_id(@event), 2: html: { method: :delete }) do |f| %> 3: <%= f.submit "Leave", class: "btn btn-large" %> 4: <% end %> events_controller.rb def show @event = Event.find(params[:id]) @user = current_user end Here's the models rsvp.rb class Rsvp < ActiveRecord::Base attr_accessible :joined_id belongs_to :joiner, class_name: "User" belongs_to :joined, class_name: "User" validates :joiner_id, presence: true validates :joined_id, presence: true end user.rb has_many :rsvps, foreign_key: "joiner_id", dependent: :destroy has_many :joined_events, through: :rsvps, source: :joined has_many :reverse_rsvps, foreign_key: "joined_id", class_name: "Rsvp", dependent: :destroy has_many :joiners, through: :reverse_rsvps, source: :joiner event.rb belongs_to :user has_many :rsvps, foreign_key: "joiner_id", dependent: :destroy has_many :joined_events, through: :rsvps, source: :joined has_many :reverse_rsvps, foreign_key: "joined_id", class_name: "Rsvp", dependent: :destroy has_many :joiners, through: :reverse_rsvps, source: :joiner

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  • is XULRUNNER suitable as a replacement for other C++ desktop applications frameworks such as QT?

    - by Gabriel Cuvillier
    XulRunner/Gecko seems to be really interesting for developing gui-intensive applications (by using widely used technologies such as HTML / CSS / SVG / XUL / Javascript). But the underlaying C++ APIS (XPCOM, NECKO, ...) looks so old and complex. Moreover the general lack of documentation/developper tools is really frightening. On the other hand, QT have a quite nice platform, and is well documented and supported. The UI part is really "traditional" though. What are your experiences with XULRUNNER, specially compared to other C++ desktop applications frameworks such as QT/GTK/MFC...? What is missing? What is awesome? Side question: If I wanted to migrate an existing MFC app to a cross platform C++ desktop application framework, would it be wise to use XULRUNNER instead of QT or GTK?

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  • Add all lines multiplied by another line in another table

    - by russell
    Hi, I hope I can explain this good enough. I have 3 tables. wo_parts, workorders and part2vendor. I am trying to get the cost price of all parts sold in a month. I have this script. $scoreCostQuery = "SELECT SUM(part2vendor.cost*wo_parts.qty) as total_score FROM part2vendor INNER JOIN wo_parts ON (wo_parts.pn=part2vendor.pn) WHERE workorder=$workorder"; What I am trying to do is each part is in wo_parts (under partnumber [pn]). The cost of that item is in part2vendor (under part number[pn]). I need each part price in part2vendor to be multiplied by the quantity sold in wo_parts. The way all 3 tie up is workorders.ident=wo_parts.workorder and part2vendor.pn=wo_parts.pn. I hope someone can assist. The above script does not give me the same total as when added by calculator.

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  • Gluing tiles together using imagemagick's montage command

    - by AP257
    This seems like it might be a reasonably common question, so I'm going to ask it using as many keywords as I can think of! I have a bunch of (well, nine) tile jpegs, with standard tile filenames. Each jpeg is 220x175 pixels: (top row) tile_1_0_0.jpg tile_1_1_0.jpg tile_1_2_0.jpg (middle row) tile_1_0_1.jpg tile_1_1_1.jpg tile_1_2_1.jpg (bottom row) tile_1_0_2.jpg tile_1_1_2.jpg tile_1_2_2.jpg How can I use imagemagick/montage to 'glue' or join them all together to make a single, coherent image? I don't want to resize them at all, so I guess the final image should be 660x525. That would be montage with no framing, shadowing, bordering, etc - just the nine original images, glued together to make a single jpeg. I know it should be something along these lines, but I'm struggling with getting the order and sizing right: montage +frame +shadow +label -tile 3x3 -geometry <options> *.jpg joined.jpg

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