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  • How can I calculate the sum of all positive integers less than n? [closed]

    - by Adrian Godong
    I have the following function: f(n) = f(n - 1) + (n - 1) f(0) = 0 n >= 0 I have n declared on column A, and need the result of f(n) on column B. I'm trying to find the Excel formula equivalent for this function. Sample Result: A | B --+-- 0 | 0 or: A | B --+-- 1 | 0 or: A | B --+-- 4 | 6 but never: A | B --+-- 0 | 0 1 | 0 2 | 1 ... The biggest problem is, I can't simulate the value of f(n - 1). So referencing the previous row like the above example is invalid. I'm almost sure the answer is trivial, I just can't find it.

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  • How to convert List<int> to string[]?

    - by George Edison
    I need an easy way to convert a List<int> to a string array. I have: var the_list = new List<int>(); the_list.Add(1); the_list.Add(2); the_list.Add(3); string[] the_array = new string[the_list.Count]; for(var i = 0 ; i < the_array.Count; ++i) the_array[i] = the_list[i].ToString(); ...which looks to be very ugly to me. Is there an easier way? Note: I'm looking for an easier way - not necessarily a faster way.

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  • Conditional Batch file renaming with mysql data

    - by Paul Stevens
    Hello, I wonder if anyone knows how could I rename multiple files, all of them originally named with same structure, and add some data extracted from a mysql DB according to specifics rules. For example I have 500 files named with this vars: ID NAME ADDRESS PHONE.wav = 1234567 PAULSIMON WESTDR122 9942213456.wav Now I need to rename files taking some data from the databases for each file, and append the data from a query appended to the filename. For example add the data resulting from a query Where some conditions match, and the data to build the query is taked from original file name, as ID or NAME. i other words, lets say that I want to build a query taking ID & NAME from file 1234567 PAULSIMON WESTDR123 9942213456.wav as WHERE statements to take another value as BirthDATE and add this to new filename, so final result should be: ID NAME ADDRESS PHONE BIRTHDATE.wav I will appreciate any help on this. I need this to be done on a LINUX server.

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  • Regex expression with leading zero

    - by user1874087
    I'm rather new to regex expressions and need help with a simple expression. I'm using Pentaho for ETL (Replace in String transformation) and I have column values that I need to add leading zeros to and parse out text as part of the database import. So far I have been unable to add the leading zero. The column is called Region and the values are "region 8", "region 10", "region 11". My regex expression is ['Region'] which will eliminate the region text but produces results = "8", "10", "11". I need values to produce "08", "10", "11". So all the single digit numbers must have leading zeros.

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  • How can we copy datacolumn with data from one table to another ?

    - by Harikrishna
    I have one Datatable like DataTable addressAndPhones; And there are four columns name,address,phoneno,and other details and I only want two columns Name and address from that so I do for that is DataTable addressAndPhones2; addressAndPhones2.Columns.Add(new DataColumn(addressAndPhones.Columns["name"].ColumnName)); addressAndPhones2.Columns.Add(new DataColumn(addressAndPhones.Columns["address"].ColumnName)); But it gives me error so how can I copy fix no of columns data from one table to another table ? ERROR :Object reference not set to an instance of an object. EDIT : Only column is copied to another table, data of that column is not copied to another table.

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  • Visual Studio: Link executable

    - by smerlin
    Lets say I have: a static library project called "LIB" a application project called "LIBAPP" a application project called "APP" a application project called "APPTEST" When i add "LIB" to LIBAPP Project Dependencies, Visual Studio automatically links "LIBAPP" against LIB. But when i add APP to APPTEST Project Dependencies, it doesnt. Since i am doing unit tests of APP's classes in APPTEST, i have to link against APP, therefore i am currently manually linking against all *.obj files of APP (hundreds...) Since i have to change the link targets of APPTEST everytime i add or remove a *.cpp file from APP, this isnt a nice solution. So is there a way to force Visual Studio to do this for me automatically, like it does when adding a static library Project Dependency ?

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  • tkinter python entry not being displayed

    - by user1050619
    I have created a Form with labels and entries..but for some reason the entries are not being created, peoplegui.py from tkinter import * from tkinter.messagebox import showerror import shelve shelvename = 'class-shelve' fieldnames = ('name','age','job','pay') def makewidgets(): global entries window = Tk() window.title('People Shelve') form = Frame(window) form.pack() entries = {} for (ix, label) in enumerate(('key',) + fieldnames): lab = Label(form, text=label) ent = Entry(form) lab.grid(row=ix, column=0) lab.grid(row=ix, column=1) entries[label] = ent Button(window, text="Fetch", command=fetchRecord).pack(side=LEFT) Button(window, text="Update", command=updateRecord).pack(side=LEFT) Button(window, text="Quit", command=window.quit).pack(side=RIGHT) return window def fetchRecord(): print('In fetch') def updateRecord(): print('In update') if __name__ == '__main__': window = makewidgets() window.mainloop() When I run it the labels are created but not the entries.

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  • How to discover table properties from SQLAlchemy mapped object

    - by ssaboum
    Hi, My point is i have a class mapped with a table, in my case in a declarative way, and i want to "discover" table properties, columns, names, relations, from this class : engine = create_engine('sqlite:///' + databasePath, echo=True) # setting up root class for declarative declaration Base = declarative_base(bind=engine) class Ship(Base): __tablename__ = 'ships' id = Column(Integer, primary_key=True) name = Column(String(255)) def __init__(self, name): self.name = name def __repr__(self): return "<Ship('%s')>" % (self.name) So now my goal is from the "Ship" class to get the table columns and their properties from another piece of code. I guess i can deal with it using instrumentation but is there any way provided by the SQLAlchemy API ? Thank you.

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  • PHP/MySQL: Check if something 'belongs-to' something else?

    - by Nebs
    I have two tables: Stores and Items. The relationship is: Stores 1---* Items In PHP/MySQL what would be the best (fastest/simplest) way to check if a particular item belongs to a particular store. In other words given for example: $store_id = 1; $item_id = 12; I want to check if item 12 belongs to store 1 (and not some other store). I usually do a select on Items matching both the store_id and item_id and limit the results to 1. Then check how many rows (0 or 1) were returned with mysql_num_rows. Is there a better way? Update: Both tables have an "id" column. The Items table has a "store_id" column.

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  • SQLite subquery syntax/error/difference from MySQL

    - by Rudie
    I was under the impression this is valid SQLite syntax: SELECT *, (SELECT amount AS target FROM target_money WHERE start_year <= p.bill_year AND start_month <= p.bill_month ORDER BY start_year ASC, start_month ASC LIMIT 1) AS target FROM payments AS p; But I guess it's not, because SQLite returns this error: no such column: p.bill_year What's wrong with how I refer to p.bill_year? Yes, I am positive table payments hosts a column bill_year. Am I crazy or is this just valid SQL syntax? It would work in MySQL wouldn't it?? I don't have any other SQL present so I can't test others, but I thought SQLite was quite standardlike.

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  • How to detect crashing tabed webbrowser and handle it?

    - by David Eaton
    I have a desktop application (forms) with a tab control, I assign a tab and a new custom webrowser control. I open up about 10 of these tabs. Each one visits about 100 - 500 different pages. The trouble is that if 1 webbrowser control has a problem it shuts down the entire program. I want to be able to close the offending webbrowser control and open a new one in it's place. Is there any event that I need to subscribe to catch a crashing or unresponsive webbrowser control ? I am using C# on windows 7 (Forms), .NET framework v4 =============================================================== UPDATE: 1 - The Tabbed WebBrowser Example Here is the code I have and How I use the webbrowser control in the most basic way. Create a new forms project and name it SimpleWeb Add a new class and name it myWeb.cs, here is the code to use. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows.Forms; using System.Security.Policy; namespace SimpleWeb { //inhert all of webbrowser class myWeb : WebBrowser { public myWeb() { //no javascript errors this.ScriptErrorsSuppressed = true; //Something we want set? AssignEvents(); } //keep near the top private void AssignEvents() { //assign WebBrowser events to our custom methods Navigated += myWeb_Navigated; DocumentCompleted += myWeb_DocumentCompleted; Navigating += myWeb_Navigating; NewWindow += myWeb_NewWindow; } #region Events //List of events:http://msdn.microsoft.com/en-us/library/system.windows.forms.webbrowser_events%28v=vs.100%29.aspx //Fired when a new windows opens private void myWeb_NewWindow(object sender, System.ComponentModel.CancelEventArgs e) { //cancel all popup windows e.Cancel = true; //beep to let you know canceled new window Console.Beep(9000, 200); } //Fired before page is navigated (not sure if its before or during?) private void myWeb_Navigating(object sender, System.Windows.Forms.WebBrowserNavigatingEventArgs args) { } //Fired after page is navigated (but not loaded) private void myWeb_Navigated(object sender, System.Windows.Forms.WebBrowserNavigatedEventArgs args) { } //Fired after page is loaded (Catch 22 - Iframes could be considered a page, can fire more than once. Ads are good examples) private void myWeb_DocumentCompleted(System.Object sender, System.Windows.Forms.WebBrowserDocumentCompletedEventArgs args) { } #endregion //Answer supplied by mo. (modified)? public void OpenUrl(string url) { try { //this.OpenUrl(url); this.Navigate(url); } catch (Exception ex) { MessageBox.Show("Your App Crashed! Because = " + ex.ToString()); //MyApplication.HandleException(ex); } } //Keep near the bottom private void RemoveEvents() { //Remove Events Navigated -= myWeb_Navigated; DocumentCompleted -= myWeb_DocumentCompleted; Navigating -= myWeb_Navigating; NewWindow -= myWeb_NewWindow; } } } On Form1 drag a standard tabControl and set the dock to fill, you can go into the tab collection and delete the pre-populated tabs if you like. Right Click on Form1 and Select "View Code" and replace it with this code. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using mshtml; namespace SimpleWeb { public partial class Form1 : Form { public Form1() { InitializeComponent(); //Load Up 10 Tabs for (int i = 0; i <= 10; i++) { newTab("Test_" + i, "http://wwww.yahoo.com"); } } private void newTab(string Title, String Url) { //Create a new Tab TabPage newTab = new TabPage(); newTab.Name = Title; newTab.Text = Title; //create webbrowser Instance myWeb newWeb = new myWeb(); //Add webbrowser to new tab newTab.Controls.Add(newWeb); newWeb.Dock = DockStyle.Fill; //Add New Tab to Tab Pages tabControl1.TabPages.Add(newTab); newWeb.OpenUrl(Url); } } } Save and Run the project. Using the answer below by mo. , you can surf the first url with no problem, but what about all the urls the user clicks on? How do we check those? I prefer not to add events to every single html element on a page, there has to be a way to run the new urls thru the function OpenUrl before it navigates without having an endless loop. Thanks.

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  • Type parameterization in Scala

    - by horatius83
    So I'm learning Scala at the moment, and I'm trying to create an abstract vector class with a vector-space of 3 (x,y,z coordinates). I'm trying to add two of these vectors together with the following code: package math class Vector3[T](ax:T,ay:T,az:T) { def x = ax def y = ay def z = az override def toString = "<"+x+", "+y+", "+z+">" def add(that: Vector3[T]) = new Vector3(x+that.x, y+that.y, z+that.z) } The problem is I keep getting this error: error: type mismatch; found : T required: String def add(that: Vector3[T]) = new Vector3(x+that.x, y+that.y, z+that.z) I've tried commenting out the "toString" method above, but that doesn't seem to have any effect. Can anyone tell me what I'm doing wrong?

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  • Constant in Hibernate Mapping Files

    - by bertolami
    I would like to add a value object to a mapped class where one column is fixed depending of the class that contains the component. How can I do something like this? <component name="aComponent"> <property name="abc" column="cde"/> <property name="xyz" value="FIXED"/> </component> Unfortunatly, the value attribute does not exist. Is there another way to apply a constant value to property? Thanks in advance.

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  • What other Freemarker JSP Tag libraries are out-there?

    - by Mat Banik
    I have been using Freemarker for a while and found displaytag library very useful. I just wondering if there are any other libraries that could be used in similar means as displaytag, which have been very helpful to you in development: FTL page <#assign display=JspTaglibs["/WEB-INF/tlds/displaytag.tld"]/> <@display.table uid="items" name="items" pagesize=10 class="table"> <@display.column title="Category" property="category.name"/> <@display.column title="Delivery" property="delivery"/> </@display.table> Example of usage would be appreciated since most of the JSP tag libs don't have them.

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  • Is there a way to query if array field contains a certain value in Doctrine2?

    - by dpimka
    Starting out with Symfony2 + Doctrine. I have a table with User objects (fos_user), for which my schema contains a roles column of an 'array' type. Doctrine saves fields of this type by serializing them from php 'array' to 'longtext' (in mysql's case). So let's say I have the following users saved into DB: **User1**: array(ROLE_ADMIN, ROLE_CUSTOM1) **User2**: array(ROLE_ADMIN, ROLE_CUSTOM2) **User3**: array(ROLE_CUSTOM2) Now in my controller I want to select all users with ROLE_ADMIN set. Is there a way to write a DQL query which would directly return me User1 and User2? Or do I need to fetch all users to have Doctrine to unserialize roles column and then for each of them do in_array('ROLE_ADMIN', $user-getRoles())? I have searched the DQL part of the manual, but so far did not find anything similar to my needs...

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  • ASP.NET MVC: trying out a script injection hangs Visual Studio 2010 completely?

    - by Mark Redman
    Wondering if anyone has an idea of whats going on: I am new to ASP.NET MVC and am trying out a few things with jquery/ajax. The basic scenario is a dropdownlist with an add button next to it. Clicking the add button launches a jquery ui dialog with a textbox form, entering a value saves the item to the database and refreshes the drop-downlist. The dropdownlist is re-populated using a JSON result. This all works ok. I thought I would try a script injetion attack, ie add the text: alert("oh dear") to seee what would happen and to check if I need to encode anything. When I try and save this item (similar to the same process of adding a plain text entry) Visual Studio 2010 Beta 2 hangs completely. Any ideas? UPDATE: It happens when posting: "</"

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  • addDoubleClickHandler to a FixedWidthGrid !!

    - by MArio
    Hello so I got a FixedWidthGrid table which is made from a pagingtable FixedWidthGrid dataTable = x.getDataTable(); I could add alot of handlers to the dataTables rows like selected or sort policies. but I cant add a double click handler ... anyway idea's ?! thank you I do have a class which I made to try to add a double click hander but it didn't work. class: public class DoubleClickTable extends FixedWidthGrid implements HasDoubleClickHandlers { public DoubleClickTable() { super(); } public HandlerRegistration addDoubleClickHandler(DoubleClickHandler handler) { return addDomHandler(handler, DoubleClickEvent.getType()); } } Thank you so much for your help.

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  • numberOfSectionsInTableView is requested in/after viewDidLoad ONLY if tableview is empty

    - by Ben Packard
    A simple tableviewController, empty. A modal that can be launched from a button. No data in the data source for the tableview, and no rows displayed. I open the modal, use it to add an item, and return to the tableview controller. The tableview updates itself automatically, and the new row is displayed. I add a second item. The table view does NOT update automatically. I can tell by logging inside numberOfSectionsInTableView that even if I go to add the first item and cancel, the tableview refreshes - it asks for the number of sections, rows, and the cell to display (if there is one). But not if there is one pre-existing row in the table. I've scoured my code but can't find anything that would cause the tableview to know when the first item is added, but none afterwards. Any ideas? EDIT - I have further narrowed my issue so will close this shortly and post a more specific question

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  • Get DataGridView checkbox cell value?

    - by George
    Hello guys. I'm having a strange issue here. I have a 3 column datagrid that is filled by a connection with the database. So far so good. I have an extra column, of checkbox type. I need to get it's value for perfoming a bulk operation on it. Here is the catch: When all cells are selected, it works fine. But when an user selects any cell that its not the first, software gives me a object reference exception. Here is the code public List<String> GetSelected() { List<String> selected = new List<String>(); foreach(DataGridViewRow row in datagrid.rows) { if ((Boolean)row.Cells[wantedCell].Value == true) { selected.Add(row.Cells[anotherCell]); } } } I tracked down the failure to the if-test, throwing a exception, because the value of the cell is read as null. Any thougths? Thanks

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  • Data frame linear fit in R

    - by user1247384
    This is perhaps a simple question, but I am n00b.Say I have a data frame with a bunch of columns. I need to call lm function over the column 1 and 2, 1 and 3, and so on. So basically I need to loop over all columns and store the results of the fit as I build the model. The problem I am running into is that lm(df[1]~df[2], data = df) doesnt work. In this case df is the data frame object and df[1] is the first column. What is a good way to do this in a loop, as in access the columns of df in an iterative fashion. Thanks.

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  • disable a form in asp.net..

    - by rohit
    hi iam working on asp.net using c# project...iam facing a problem...the problem is,i had a master page in which iam using collapse pannel(ajax control)... in collapse pannel i had folders like:- xyz abc def ghi.... and in xyz folder i had some forms.... nw the problem is that i had a search menu in my main page(comes after login)...after searching a grid view is open and in that there is a column name (suppose) XYZ...so when i click on items in that column then only i want xyz folder to be enable or viewed so that i acess forms in that folder....hw cud i do that..i search alot but didn't get the solution..plz help me go through this...

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  • Can MySQL reasonably perform queries on billions of rows?

    - by haxney
    I am planning on storing scans from a mass spectrometer in a MySQL database and would like to know whether storing and analyzing this amount of data is remotely feasible. I know performance varies wildly depending on the environment, but I'm looking for the rough order of magnitude: will queries take 5 days or 5 milliseconds? Input format Each input file contains a single run of the spectrometer; each run is comprised of a set of scans, and each scan has an ordered array of datapoints. There is a bit of metadata, but the majority of the file is comprised of arrays 32- or 64-bit ints or floats. Host system |----------------+-------------------------------| | OS | Windows 2008 64-bit | | MySQL version | 5.5.24 (x86_64) | | CPU | 2x Xeon E5420 (8 cores total) | | RAM | 8GB | | SSD filesystem | 500 GiB | | HDD RAID | 12 TiB | |----------------+-------------------------------| There are some other services running on the server using negligible processor time. File statistics |------------------+--------------| | number of files | ~16,000 | | total size | 1.3 TiB | | min size | 0 bytes | | max size | 12 GiB | | mean | 800 MiB | | median | 500 MiB | | total datapoints | ~200 billion | |------------------+--------------| The total number of datapoints is a very rough estimate. Proposed schema I'm planning on doing things "right" (i.e. normalizing the data like crazy) and so would have a runs table, a spectra table with a foreign key to runs, and a datapoints table with a foreign key to spectra. The 200 Billion datapoint question I am going to be analyzing across multiple spectra and possibly even multiple runs, resulting in queries which could touch millions of rows. Assuming I index everything properly (which is a topic for another question) and am not trying to shuffle hundreds of MiB across the network, is it remotely plausible for MySQL to handle this? UPDATE: additional info The scan data will be coming from files in the XML-based mzML format. The meat of this format is in the <binaryDataArrayList> elements where the data is stored. Each scan produces = 2 <binaryDataArray> elements which, taken together, form a 2-dimensional (or more) array of the form [[123.456, 234.567, ...], ...]. These data are write-once, so update performance and transaction safety are not concerns. My naïve plan for a database schema is: runs table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | start_time | TIMESTAMP | | name | VARCHAR | |-------------+-------------| spectra table | column name | type | |----------------+-------------| | id | PRIMARY KEY | | name | VARCHAR | | index | INT | | spectrum_type | INT | | representation | INT | | run_id | FOREIGN KEY | |----------------+-------------| datapoints table | column name | type | |-------------+-------------| | id | PRIMARY KEY | | spectrum_id | FOREIGN KEY | | mz | DOUBLE | | num_counts | DOUBLE | | index | INT | |-------------+-------------| Is this reasonable?

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  • How do you access the value of an SQL count () query in a Java program

    - by Ankur
    I want to get to the value I am finding using the COUNT command of SQL. Normally I enter the column name I want to access into the getInt() getString() method, what do I do in this case when there is no specific column name. I have used 'AS' in the same manner as is used to alias a table, I am not sure if this is going to work, I would think not. Statement stmt3 = con.createStatement(); ResultSet rs3 = stmt3.executeQuery("SELECT COUNT(*) FROM "+lastTempTable+") AS count"); while(rs3.next()){ count = rs3.getInt("count"); }

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  • alter mysqldump file before import

    - by julio
    Hi-- I have a mysqldump file created from an earlier version of a product that can't be imported into a new version of the product, since the db structure has changed slightly (mainly altering a column that was NOT NULL DEFAULT 0 to UNIQUE KEY DEFAULT NULL). If I just import the old dump file, it will error out since the column that has default values of 0 now breaks the UNIQUE constraint. It would be easy enough to either manually alter the mysqldump file, or import into a temp table and change it, then copy to the new table. However, is there a way to do this programatically, so it will be repeatable and not manual? (this will need to happen for many instances of this product). I'm thinking something like disabling key constraints for the import, then setting all values that = 0 to NULL, then re-enabling the key constraints? Is this possible? Any help appreciated.

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  • Java JPA @OneToMany neededs to reciprocate @ManyToOne?

    - by bguiz
    Create Table A ( ID varchar(8), Primary Key(ID) ); Create Table B ( ID varchar(8), A_ID varchar(8), Primary Key(ID), Foreign Key(A_ID) References A(ID) ); Given that I have created two tables using the SQL statements above, and I want to create Entity classes for them, for the class B, I have these member attributes: @Id @Column(name = "ID", nullable = false, length = 8) private String id; @JoinColumn(name = "A_ID", referencedColumnName = "ID", nullable = false) @ManyToOne(optional = false) private A AId; In class A, do I need to reciprocate the many-to-one relationship? @Id @Column(name = "ID", nullable = false, length = 8) private String id; @OneToMany(cascade = CascadeType.ALL, mappedBy = "AId") private List<B> BList; //<-- Is this attribute necessary? Is it a necessary or a good idea to have a reciprocal @OneToMany for the @ManyToOne? If I make the design decision to leave out the @OneToMany annotated attribute now, will come back to bite me further down.

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