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  • Winforms connection strings from App.config

    - by Geo Ego
    I have a Winforms app that I am developing in C# that will serve as a frontend for a SQL Server 2005 database. I rolled the executable out to a test machine and ran it. It worked perfectly fine on the test machine up until the last round of changes that I made. However, now on the test machine, it throws the following exception immediately upon opening: System.NullReferenceException: Object reference not set to an instance of an object. at PSRD_Specs_Database_Administrat.mainMenu.mainMenu_Load(Object sender, EventArgs e) at System.Windows.Forms.Form.OnLoad(EventArgs e) at System.Windows.Forms.Form.OnCreateControl() at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible) at System.Windows.Forms.Control.CreateControl() at System.Windows.Forms.Control.WmShowWindow(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ScrollableControl.WndProc(Message& m) at System.Windows.Forms.ContainerControl.WndProc(Message& m) at System.Windows.Forms.Form.WmShowWindow(Message& m) at System.Windows.Forms.Form.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) The only thing that I changed in this version that pertains to mainMenu_Load is the way that the connection string to the database is called. Previously, I had set a string with the connection string on every form that I needed to call it from, like: string conString = "Data Source = SHAREPOINT;Trusted_Connection = yes;" + "database = CustomerDatabase;connection timeout = 15"; As my app grew and I added forms to it, I decided to add an App.config to the project. I defined the connection string in it: <connectionStrings> <add name="conString" providerName="System.Data.SqlClient" connectionString="Data Source = SHAREPOINT;Trusted_Connection = yes;database = CustomerDatabase;connection timeout = 15" /> </connectionStrings> I then created a static string that would return the conString: public static string GetConnectionString(string conName) { string strReturn = string.Empty; if (!(string.IsNullOrEmpty(conName))) { strReturn = ConfigurationManager.ConnectionStrings[conName].ConnectionString; } else { strReturn = ConfigurationManager.ConnectionStrings["conString"].ConnectionString; } return strReturn; } I removed the conString variable and now call the connection string like so: PublicMethods.GetConnectionString("conString").ToString() It appears that this is giving me the error. I changed these instances to directly call the connection string from App.config without using GetConnectionString. For instance, in a SQLConnection: using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["conString"].ConnectionString)) This also threw the exception. However, when I went back to using the conString variable on each form, I had no issues. What I don't understand is why all three methods work fine on my development machine, while using the App.config directly or via the static string I created throw exceptions.

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  • StringIndexOutOfBoundsException error in main method

    - by Ro Siv
    I am obtaining a StringIndexOutOfBoundsError when running my main method. Here is the output of my program in the command line. "Please enter the shift, 1 for day, 2 for night" 1 "you entered a number for the shift" "Please enter the hourly pay Rate" 2 "you entered a number for the pay Rate" "Please enter the employees name" brenda "cat6b" "your value you entered is correct 0-9 or a - z" "Please enter the employee number" 100e "cat41" "your value you entered is correct 0-9 or a - z" "Please enter current date in XXYYZZZZ format, X is day, Y is month, Z is year" 10203933 "cat81 " "your value you entered is correct 0-9 or a - z" 90 1 valye of array is 1 81 0 value of array is 0 82 2 value of array is 2 83 0 value of array is 0 84 3 value of array is 3 85 9 value of array is 9 86 3 value of array is 3 87 3 value of array is 3 "Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 8 at java.lang.String.charAt(String.java:658) at ProductionWorker<init>(ProductionWorker.java:66) at labBookFiftyFour.main(labBookFiftyFour.java:58)" "Press any key to continue . . ." Ignore the cat parts in the code, i was using a println statement to test the code. Ignore the value of array output as well, as i wanted to use an array in the program later on. Here is my main method. import java.math.*; import java.text.DecimalFormat; import java.io.*; import java.util.*; public class labBookFiftyFour { public static void main(String[] args) { Scanner myInput = new Scanner(System.in); int shift = -1; double pRate = -2; String name = " "; String number = " "; String date = " "; while(shift < 0 || pRate < 0 ) { System.out.println("Please enter the shift, 1 for day, 2 for night"); if(myInput.hasNextInt()){ System.out.println("you entered a number for the shift"); shift = myInput.nextInt(); } System.out.println("Please enter the hourly pay Rate"); if(myInput.hasNextDouble()){ System.out.println("you entered a number for the pay Rate"); pRate = myInput.nextDouble(); } else if (myInput.hasNext()) { System.out.println("Please enter a proper value"); myInput.next(); } else { System.err.println("No more input"); System.exit(1); } } myInput.nextLine(); //consume newLine System.out.println("Please enter the employees name"); name = myInput.nextLine(); //use your isValid method if(isValid(name)) { System.out.println("your value you entered is correct 0-9 or a - z "); } System.out.println("Please enter the employee number"); number = myInput.nextLine(); //use your isValid method if(isValid(number)) { System.out.println("your value you entered is correct 0-9 or a - z "); } System.out.println("Please enter current date in XXYYZZZZ format, X is day, Y is month, Z is year"); date = myInput.nextLine(); //use your isValid method if(isValid(date)) { System.out.println("your value you entered is correct 0-9 or a - z "); } ProductionWorker myWorker = new ProductionWorker(shift, pRate, name, number, date); //int day and night , double payRate System.out.println("THis is the shift " + myWorker.getShift() + " This is the pay Rate " + myWorker.getPRate() + " " + myWorker.getName() + " " + myWorker.getNumber() + " " + myWorker.getDate()); } //Made this method for testing String input for 0-9 or a - z values , put AFTER main method, but before end of class public static boolean isValid(String stringName) //This method has to be static, for some reason? { System.out.println("cat" + stringName.length() + stringName.charAt(0)); boolean flag = true; int index = 0; while(index < stringName.length()) { if(Character.isLetterOrDigit(stringName.charAt(index))) { flag = true; } else { flag = false; } ++index; } return flag; } } Here is my employeeOne. java Superclass public class employeeOne { private String name; private String number; private String date; public employeeOne(String name, String number, String date) { this.name = name; this.number = number; this.date = date; } public String getName() { return name; } public String getNumber() { return number; } public String getDate() { return date; } } Here is my ProductionWorker.java subclass, which extends employeeOne public class ProductionWorker extends employeeOne { private int shift; //shift represents day or night, day = 1, night = 2 private double pRate; //hourly pay rate public ProductionWorker(int shift, double pRate, String name, String number, String date) { super(name, number, date); this.shift = shift; if(this.shift >= 3 || this.shift <= 0) { System.out.println("You entered an out of bounds shift date, enter 1 for day or 2 for night, else shift will be day"); this.shift = 1; } this.pRate = pRate; boolean goodSoFar = true; int indexNum = 0; int indexDate = 0; if(name.length() <= 10 && number.length() <= 4 && date.length() < 9 ) { goodSoFar = true; } else { goodSoFar = false; } while(goodSoFar && indexNum < 3) //XXXL XXX digits 1-9, L is a letter A -M { if(Character.isDigit(number.charAt(indexNum))) { goodSoFar = true; } else { goodSoFar = false; } ++indexNum; } while(goodSoFar && indexNum < 4) { if(Character.isLetter(number.charAt(indexNum))) { goodSoFar = true; } else if(Character.isDigit(number.charAt(indexNum))) { goodSoFar = false; } else if(Character.isDigit(number.charAt(indexNum)) == false && Character.isLetter(number.charAt(indexNum)) == false) { goodSoFar = false; } ++indexNum; } int[] dateValues = new int[date.length()]; while(goodSoFar && indexDate <= date.length()) //XXYYZZZZ { System.out.println("" + date.length() + indexDate + " " + date.charAt(indexDate)); if(Character.isDigit(date.charAt(indexDate))) { dateValues[indexDate] = Character.getNumericValue(date.charAt(indexDate)); System.out.println("value of array is " + dateValues[indexDate]); ++indexDate; } else { goodSoFar = false; } } if(goodSoFar) { System.out.println("your input is good so far"); } else { System.out.println("your input is wrong for name or number or date"); } } public int getShift() { return shift; } public double getPRate() { return pRate; } }

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  • Best practice Java - String array constant and indexing it

    - by Pramod
    For string constants its usual to use a class with final String values. But whats the best practice for storing string array. I want to store different categories in a constant array and everytime a category has been selected, I want to know which category it belongs to and process based on that. Addition : To make it more clear, I have a categories A,B,C,D,E which is a constant array. Whenever a user clicks one of the items(button will have those texts) I should know which item was clicked and do processing on that. I can define an enum(say cat) and everytime do if clickedItem == cat.A .... else if clickedItem = cat.B .... else if .... or even register listeners for each item seperately. But I wanted to know the best practice for doing handling these kind of problems.

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  • From the Coalface - 4 - Getting a connection string

    - by TATWORTH
    Creating a connection string by hand is quite difficult, however you create a connection string as follows: 1) Create an empty text file in windows explorer and rename it to X.UDL 2) Double click on it and the datalink provider dialog will appear. 3) Select the provider tab. Find the provider for your data access method and click next. 4) Select your source  5) Test the connection and save it. 6) Open X.UDL with a text editor to see your connections string. You can also look at http://www.connectionstrings.com/ for examples of connection strings.

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  • Regex to String generation

    - by Mifmif
    Let's say that we have a regex and an index i , if we suppose that the set of string that match our regex are sorted in a lexicographical order, how could we get the i element of this list ? Edit : I added this simple example for more explanation : input : regex="[a-c]{1,2}"; index=4; in this case the ordered list of string that matches this regex contains those elements : a aa ab ac b ba bb bc c ca cb cc output : the 4th element which is ac ps: it's known that the string list that match the regex have infinite element, this doesn't have an impact on the proccess of extracting the element in the given index.

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  • how to use string::find to look for a word rather each character seperately

    - by RubyKing
    Hello how would I look through a string for a word rather then each character in that word. I have my code here and it always seems to find everything that is .obj even if its o or b or j or "." is there anyway to get passed this here is my code? I checked the docuementation here link but nothing returned any results I craved so hard string &str = *it; if(it->find(".obj")) { cout << "Found .Obj" << endl; } I also tried to use string::compare but that failed :(

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  • How to parse json string to dataset in C#

    - by Samir R. Bhogayta
    // Serialization of DataSet to json string StringWriter sw = new StringWriter(); versionUpGetData.WriteXml(sw, XmlWriteMode.WriteSchema); XmlDocument xd = new XmlDocument(); xd.LoadXml(sw.ToString()); String jsonText = JsonConvert.SerializeXmlNode(xd); File.WriteAllText(“d:/datasetJson.txt”,jsonText); //Deserialization of Json String to DataSet XmlDocument xd1 = new XmlDocument(); xd1 = (XmlDocument)JsonConvert.DeserializeXmlNode(jsonText); DataSet jsonDataSet = new DataSet(); jsonDataSet.ReadXml(new XmlNodeReader(xd1));

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  • Appropriate design / technologies to handle dynamic string formatting?

    - by Mark W
    recently I was tasked with implementing a way of adding support for versioning of hardware packet specifications to one of our libraries. First a bit of information about the project. We have a hardware library which has classes for each of the various commands we support sending to our hardware. These hardware modules are essentially just lights with a few buttons, and a 2 or 4 digit display. The packets typically follow the format {SOH}AADD{ETX}, where AA is our sentinel action code, and DD is the device ID. These packet specs are different from one command to the next obviously, and the different firmware versions we have support different specifications. For example, on version 1 an action code of 14 may have a spec of {SOH}AADDTEXT{ETX} which would be AA = 14 literal, DD = device ID, TEXT = literal text to display on the device. Then we come out with a revision with adds an extended byte(s) onto the end of the packet like this {SOH}AADDTEXTE{ETX}. Assume the TEXT field is fixed width for this example. We have now added a new field onto the end which could be used to say specify the color or flash rate of the text/buttons. Currently this java library only supports one version of the commands, the latest. In our hardware library we would have a class for this command, say a DisplayTextArgs.java. That class would have fields for the device ID, the text, and the extended byte. The command class would expose a method which generates the string ("{SOH}AADDTEXTE{ETX}") using the value from the class. In practice we would create the Args class as needed, populate the fields, call the method to get our packet string, then ship that down across the CAN. Some of our other commands specification can vary for the same command, on the same version, depending on some runtime state. For example, another command for version 1 may be {SOH}AA{ETX}, where this action code clears all of the modules behind a specific controller device of their text. We may overload this packet to have option fields with multiple meanings like {SOH}AAOC{ETX} where OC is literal text, which tells the controller to only clear text on a specific module type, and to leave the others alone, or the spec could also have an option format of {SOH}AADD{ETX} to clear the text off a a specific device. Currently, in the method which generates the packet string, we would evaluate fields on the args class to determine which spec we will be using when formatting the packet. For this example, it would be along the lines of: if m_DeviceID != null then use {SOH}AADD{ETX} else if m_ClearOCs == true then use {SOH}AAOC{EXT} else use {SOH}AA{ETX} I had considered using XML, or a database to store String.format format strings, which were linked to firmware version numbers in some table. We would load them up at startup, and pass in the version number of the hardwares firmware we are currently using (I can query the devices for their firmware version, but the version is not included in all packets as part of the spec). This breaks down pretty quickly because of the dynamic nature of how we select which version of the command to use. I then considered using a rule engine to possibly build out expressions which could be interpreted at runtume, to evaluate the args class's state, and from that select the appropriate format string to use, but my brief look at rule engines for java scared me away with its complexity. While it seems like it might be a viable solution, it seems overly complex. So this is why I am here. I wouldn't say design is my strongest skill, and im having trouble figuring out the best way to approach this problem. I probably wont be able to radically change the args classes, but if the trade off was good enough, I may be able to convince my boss that the change is appropriate. What I would like from the community is some feedback on some best practices / design methodologies / API or other resources which I could use to accomplish: Logic to determine which set of commands to use for a given firmware version Of those command, which version of each command to use (based on the args classes state) Keep the rules logic decoupled from the application so as to avoid needing releases for every firmware version Be simple enough so I don't need weeks of study and trial and error to implement effectively.

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  • Database Design Primay Key, ID vs String

    - by LnDCobra
    Hi, I am currently planning to develop a music streaming application. And i am wondering what would be better as a primary key in my tables on the server. An ID int or a Unique String. Methods 1: Songs Table: SongID(int), Title(string), Artist*(string), Length(int), Album*(string) Genre Table Genre(string), Name(string) SongGenre: SongID*(int), Genre*(string) Method 2 Songs Table: SongID(int), Title(string), ArtistID*(int), Length(int), AlbumID*(int) Genre Table GenreID(int), Name(string) SongGenre: SongID*(int), GenreID*(int) Key: Bold = Primary Key, Field* = Foreign Key I'm currently designing using method 2 as I believe it will speed up lookup performance and use less space as an int takes a lot less space then a string. Is there any reason this isn't a good idea? Is there anything I should be aware of?

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  • Is the Contains Method in java.lang.String Case-sensitive?

    - by Kamikaze Mercenary
    Say I have 2 strings, String s1 = "AbBaCca"; String s2 = "bac"; I want to preform a check returning that s2 is contained within s1. I can do this with: return s1.contains(s2); I am pretty sure that contains() is case sensitive, however I can't determine this for sure from reading the documentation. If it is then I suppose my best method would be something like: return s1.toLowerCase().contains(s2.toLowerCase()); All this aside, does anyone know of another (possibly better) way to accomplish this without caring about case-sensitivity?

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  • Is it possible to temporarily disable Python's string interpolation?

    - by dangerouslyfacetious
    I have a python logger set up, using python's logging module. I want to store the string I'm using with the logging Formatter object in a configuration file using the ConfigParser module. The format string is stored in a dictionary of settings in a separate file that handles the reading and writing of the config file. The problem I have is that python still tries to format the file and falls over when it reads all the logging-module-specific formatting flags. { "log_level":logging.debug, "log_name":"C:\\Temp\\logfile.log", "format_string": "%(asctime)s %(levelname)s: %(module)s, line %(lineno)d - %(message)s" } My question is simple: how can I disable the formatting functionality here while keeping it elsewhere. My initial reaction was copious use of the backslash to escape the various percent symbols, but that of course permanently breaks the formatting such that it wont work even when I need it to. Also, general pointers on good settings-file practices would be nice. This is the first time I've done anything significant with ConfigParser (or logging for that matter). Thanks in advance, Dominic

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  • How to perform a literal match with regex using wildcard

    - by kashif4u
    I am trying to perform literal match with regular expression using wildcard. string utterance = "Show me customer id 19"; string pattern 1 = "*tom*"; string patter 2 = "*customer id [0-9]*"; Desired results: if (Regex.IsMatch(utterance, pattern 1 )) { MATCH NOT FOUND } if (Regex.IsMatch(utterance, pattern 2 )) { MATCH FOUND } I have tried looking for literal match solution/syntax in wildcard but having difficulty. Could you also enlighten me with with an example on possible Pattern Matching Strength algorithm i.e. if code match 90 select? Note: I have table with 100000 records to perform literal matches from user utterances. Thanks in advance.

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  • What to Return? Error String, Bool with Error String Out, or Void with Exception

    - by Ranger Pretzel
    I spend most of my time in C# and am trying to figure out which is the best practice for handling an exception and cleanly return an error message from a called method back to the calling method. For example, here is some ActiveDirectory authentication code. Please imagine this Method as part of a Class (and not just a standalone function.) bool IsUserAuthenticated(string domain, string user, string pass, out errStr) { bool authentic = false; try { // Instantiate Directory Entry object DirectoryEntry entry = new DirectoryEntry("LDAP://" + domain, user, pass); // Force connection over network to authenticate object nativeObject = entry.NativeObject; // No exception thrown? We must be good, then. authentic = true; } catch (Exception e) { errStr = e.Message().ToString(); } return authentic; } The advantages of doing it this way are a clear YES or NO that you can embed right in your If-Then-Else statement. The downside is that it also requires the person using the method to supply a string to get the Error back (if any.) I guess I could overload this method with the same parameters minus the "out errStr", but ignoring the error seems like a bad idea since there can be many reasons for such a failure... Alternatively, I could write a method that returns an Error String (instead of using "out errStr") in which a returned empty string means that the user authenticated fine. string AuthenticateUser(string domain, string user, string pass) { string errStr = ""; try { // Instantiate Directory Entry object DirectoryEntry entry = new DirectoryEntry("LDAP://" + domain, user, pass); // Force connection over network to authenticate object nativeObject = entry.NativeObject; } catch (Exception e) { errStr = e.Message().ToString(); } return errStr; } But this seems like a "weak" way of doing things. Or should I just make my method "void" and just not handle the exception so that it gets passed back to the calling function? void AuthenticateUser(string domain, string user, string pass) { // Instantiate Directory Entry object DirectoryEntry entry = new DirectoryEntry("LDAP://" + domain, user, pass); // Force connection over network to authenticate object nativeObject = entry.NativeObject; } This seems the most sane to me (for some reason). Yet at the same time, the only real advantage of wrapping those 2 lines over just typing those 2 lines everywhere I need to authenticate is that I don't need to include the "LDAP://" string. The downside with this way of doing it is that the user has to put this method in a try-catch block. Thoughts? Is there another way of doing this that I'm not thinking of?

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  • Using C preprocessor to construct a string literal for scanf?

    - by Brett
    I'm attempting to create an sscanf string literal to aid in buffer overrun prevention in C99. The goal is something like: #define MAX_ARG_LEN 16 char arg[MAX_ARG_LEN] = ""; if (sscanf(arg, "%"(MAX_ARG_LEN-1)"X", &input) > 0) The obvious "manual" solution is something like: #define MAX_ARG_LEN 16 #define MAX_ARG_CHARS "15" char arg[MAX_ARG_LEN] = ""; if (sscanf(arg, "%"MAX_ARG_CHARS"X", &input) > 0) However, I would prefer something to automatically generate "%15X" given a buffer size of 16. This link is almost works for my application: http://stackoverflow.com/questions/240353/convert-a-preprocessor-token-to-a-string but it does not handle the -1. Suggestions?

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  • Where to put constant strings in C++: static class members or anonymous namespaces

    - by stone
    I need to define some constant strings that will be used only by one class. It looks like I have three options: Embed the strings directly into locations where they are used. Define them as private static constant members of the class: //A.h class A { private: static const std::string f1; static const std::string f2; static const std::string f3; }; //A.cpp const std::string f1 = "filename1"; const std::string f2 = "filename2"; const std::string f3 = "filename3"; //strings are used in this file Define them in an anonymous namespace in the cpp file: //A.cpp namespace { const std::string f1 = "filename1"; const std::string f2 = "filename2"; const std::string f3 = "filename3"; } //strings are used in this file Given these options, which one would you recommend and why? Thanks.

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  • XSLT string with HTML entities - How can I get it to render as HTML?

    - by Kache4
    I'm completely new to using XSL, so if there's any information that I'm neglecting to include, just let me know. I have a string in my XSLT file that I can display like this: <xsl:value-of select="@Description/> and it shows up, rendered in a browser like: <div>My text has html entities within it</div> <div>This includes quotes, like &quot;Hello World&quot; and sometimes whitespaces.&nbsp;</div> What can I do to get this string rendered as html, so that <div></div> results in newlines, &quot; gives me ", and &nbsp gives me a space? I could elaborate on things I've already tried that haven't worked, but I don't know if that's relevant.

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  • Which connection string for MySql ODBC connector 5.2.6?

    - by stighy
    it seems i can't make work a connection to MySql using ODBC connector 5.2.6. In a 64 bit environment, in a VBA excel application, i use this string, but it not work: "Driver={MySQL ODBC 5.2 Driver}; Server=myserver;Database=mydb;User=readonly;Password=mypass;Option=3" I have also used Driver={MySQL ODBC 5.2w Driver} and Driver={MySQL ODBC 5.2a Driver} But the error is: ODBC driver unknow. Can someone help me ? Ps: it works with a DSN setted, but i would like to use a connection string so i don't go to each user computer and set a DSN. Thanks

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  • compile time if && return string reference optimization

    - by Truncheon
    Hi. I'm writing a series classes that inherit from a base class using virtual. They are INT, FLOAT and STRING objects that I want to use in a scripting language. I'm trying to implement weak typing, but I don't want STRING objects to return copies of themselves when used in the following way (instead I would prefer to have a reference returned which can be used in copying): a = "hello "; b = "world"; c = a + b; I have written the following code as a mock example: #include <iostream> #include <string> #include <cstdio> #include <cstdlib> std::string dummy("<int object cannot return string reference>"); struct BaseImpl { virtual bool is_string() = 0; virtual int get_int() = 0; virtual std::string get_string_copy() = 0; virtual std::string const& get_string_ref() = 0; }; struct INT : BaseImpl { int value; INT(int i = 0) : value(i) { std::cout << "constructor called\n"; } INT(BaseImpl& that) : value(that.get_int()) { std::cout << "copy constructor called\n"; } bool is_string() { return false; } int get_int() { return value; } std::string get_string_copy() { char buf[33]; sprintf(buf, "%i", value); return buf; } std::string const& get_string_ref() { return dummy; } }; struct STRING : BaseImpl { std::string value; STRING(std::string s = "") : value(s) { std::cout << "constructor called\n"; } STRING(BaseImpl& that) { if (that.is_string()) value = that.get_string_ref(); else value = that.get_string_copy(); std::cout << "copy constructor called\n"; } bool is_string() { return true; } int get_int() { return atoi(value.c_str()); } std::string get_string_copy() { return value; } std::string const& get_string_ref() { return value; } }; struct Base { BaseImpl* impl; Base(BaseImpl* p = 0) : impl(p) {} ~Base() { delete impl; } }; int main() { Base b1(new INT(1)); Base b2(new STRING("Hello world")); Base b3(new INT(*b1.impl)); Base b4(new STRING(*b2.impl)); std::cout << "\n"; std::cout << b1.impl->get_int() << "\n"; std::cout << b2.impl->get_int() << "\n"; std::cout << b3.impl->get_int() << "\n"; std::cout << b4.impl->get_int() << "\n"; std::cout << "\n"; std::cout << b1.impl->get_string_ref() << "\n"; std::cout << b2.impl->get_string_ref() << "\n"; std::cout << b3.impl->get_string_ref() << "\n"; std::cout << b4.impl->get_string_ref() << "\n"; std::cout << "\n"; std::cout << b1.impl->get_string_copy() << "\n"; std::cout << b2.impl->get_string_copy() << "\n"; std::cout << b3.impl->get_string_copy() << "\n"; std::cout << b4.impl->get_string_copy() << "\n"; return 0; } It was necessary to add an if check in the STRING class to determine whether its safe to request a reference instead of a copy: Script code: a = "test"; b = a; c = 1; d = "" + c; /* not safe to request reference by standard */ C++ code: STRING(BaseImpl& that) { if (that.is_string()) value = that.get_string_ref(); else value = that.get_string_copy(); std::cout << "copy constructor called\n"; } If was hoping there's a way of moving that if check into compile time, rather than run time.

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  • How do I replace values within a data frame with a string in R?

    - by Arturito
    short version: How do I replace values within a data frame with a string found within another data frame? longer version: I'm a biologist working with many species of bees. I have a data set with many thousands of bees. Each row has a unique bee ID # along with all the relevant info about that specimen (data of capture, GPS location, etc). The species information for each bee has not been entered because it takes a long time to ID them. When IDing, I end up with boxes of hundred of bees, all of the same species. I enter these into a separate data frame. I am trying to write code that will update the original data file with species information (family, genus, species, sex, etc) as I ID the bees. Currently, in the original data file, the species info is blank and is interpreted as NA within R. I want to have R find all unique bee ID #'s and fill in the species info, but I am having trouble figuring out how to replace the NA values with a string (e.g. "Andrenidae") Here is a simple example of what I am trying to do: rawData<-data.frame(beeID=c(1:20),family=rep(NA,20)) speciesInfo<-data.frame(beeID=seq(1,20,3),family=rep("Andrenidae",7)) rawData[rawData$beeID == 4,"family"] <- speciesInfo[speciesInfo$beeID == 4,"family"] So, I am replacing things as I want, but with a number rather than the family name (a string). What I would eventually like to do is write a little loop to add in all the species info, e.g.: for (i in speciesInfo$beeID){ rawData[rawData$beeID == i,"family"] <- speciesInfo[speciesInfo$beeID == i,"family"] } Thanks in advance for any advice! Cheers, Zak EDIT: I just noticed that the first two methods below add a new column each time, which would cause problems if I needed to add species info multiple times (which I typically do). For example: rawData<-data.frame(beeID=c(1:20),family=rep(NA,20)) Andrenidae<-data.frame(beeID=seq(1,20,3),family=rep("Andrenidae",7)) Halictidae<-data.frame(beeID=seq(1,20,3)+1,family=rep("Halictidae",7)) # using join library(plyr) rawData <- join(rawData, Andrenidae, by = "beeID", type = "left") rawData <- join(rawData, Halictidae, by = "beeID", type = "left") # using merge rawData <- merge(x=rawData,y=Andrenidae,by='beeID',all.x=T,all.y=F) rawData <- merge(x=rawData,y=Halictidae,by='beeID',all.x=T,all.y=F) Is there a way to either collapse the columns so that I have one, unified data frame? Or a way to update the rawData rather than adding a new column each time? Thanks in advance!

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  • How do I select and group by a portion of a string?

    - by Russ Bradberry
    Given I have data like the following, how can I select and group by portions of a string? Version Users 1.1.1 1 1.1.23 3 1.1.45 1 2.1.24 3 2.1.12 1 2.1.45 3 3.1.10 1 3.1.23 3 What I want is to sum up the users using version 1.1.x and 2.2.x and 3.3.x etc, but I'm not sure how I can group on a partial string in a select statement. edit What the data should return like is this: Version Users 1.1.XX 5 2.1.XX 7 3.1.XX 4 There is an infinite variable number of versions, some are in this format (major, minor, build) some are just major, minor and some are just major, the only time I want to "roll up" the versions is when there is a build.

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  • access EF classes from a Class Library - exactly how do configure/test the connection string in the

    - by Greg
    Hi, I'm getting very confused about how to call my EF classes in a Class Library from the Client Project I have? Things worked fine when they were in the same project. Now I'm getting errors such as "Unable to load the specified metadata resource ". I've see various ideas / suggestions re how to fix the connection string (e.g. create an App.config in your client project & copy the connection string config from your class library, something about change the connection settings to copy to output, etc) QUESTION - Can someone provide a solid way on how to get EF class access from a separate project working? (i.e. how to get the correct connection information to the client somehow) thanks

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  • Help! Obj-C/Iphone programming: extracting string from html text and reading off line by line

    - by royden
    hihi, I have this html text response from a particular website: <tr><td valign="top"><img src="/icons/image2.gif" alt="[IMG]"></td><td><a href="crsdsdfs2221.jpg">crash-2221.jpg</a></td><td align="right">14-Jun-2010 14:29 Notice for every line, there is this href=".__", which is an image file with random name and random format. I would like to extract that string within the inverted commas out so that i can append it into a URL path and download the image. I've been looking through this documentation from apple: http://developer.apple.com/mac/library/documentation/cocoa/conceptual/strings/Articles/SearchingStrings.html#//apple_ref/doc/uid/20000149-CJBBGBAI on String programming but couldn't find one that fits my bill. Also after reading it, what code can I use to ensure that I will be reading the next line the next time my function is called( because I want to download the next picture). Hope some kind soul can help me out, thanks!

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