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  • How can I check if a Perl array contains a particular value?

    - by Mel
    I am trying to figure out a way of checking for the existence of a value in an array without iterating through the array. I am reading a file for a parameter. I have a long list of parameters I do not want to deal with. I placed these unwanted parameters in an array @badparams. I want to read a new parameter and if it does not exist in @badparams, process it. If it does exist in @badparams, go to the next read.

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  • Virtual methods as Comp function to sort

    - by wilsongoncalo.mp
    Hello everyone! I'm new to C++ and i'm trying to use std::sort function to sort a vector of Solutions. The code is something like this (solution list is a *vector): void SolutionSet::sort(Comparator &comparator) { std::sort(solutionsList_->begin(), solutionsList_->end(), &comparator::compare); } The comparator param is a Comparator´s child class instance , and the compare method is virtual at Comparator class and implemented by all Comparator's child classes. And i want to use that function as a comparator function at std:sort(). Is this possible? If it is, can someone tell me how? Because with the previous code, it doesn't work. If i've not made myself clear, please just ask! Thank you guys!

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  • Compare Properties automatically

    - by juergen d
    I want to get the names of all properties that changed for matching objects. I have these (simplified) classes: public enum PersonType { Student, Professor, Employee } class Person { public string Name { get; set; } public PersonType Type { get; set; } } class Student : Person { public string MatriculationNumber { get; set; } } class Subject { public string Name { get; set; } public int WeeklyHours { get; set; } } class Professor : Person { public List<Subject> Subjects { get; set; } } Now I want to get the objects where the Property values differ: List<Person> oldPersonList = ... List<Person> newPersonList = ... List<Difference> = GetDifferences(oldPersonList, newPersonList); public List<Difference> GetDifferences(List<Person> oldP, List<Person> newP) { //how to check the properties without casting and checking //for each type and individual property?? //can this be done with Reflection even in Lists?? } In the end I would like to have a list of Differences like this: class Difference { public List<string> ChangedProperties { get; set; } public Person NewPerson { get; set; } public Person OldPerson { get; set; } } The ChangedProperties should contain the name of the changed properties.

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  • How to compare two structure strings in C++

    - by Arvandor
    Ok, so this week in class we're working with arrays. I've got an assignment that wanted me to create a structure for an employee containing an employee ID, first name, last name, and wages. Then it has me ask users for input for 5 different employees all stored in an array of this structure, then ask them for a search field type, then a search value. Lastly, display all the information for all positive search results. I'm still new, so I'm sure it isn't a terribly elegant program, but what I'm trying to do now is figure out how to compare a user entered string with the string stored in the structure... I'll try to give all the pertinent code below. struct employee { int empid, string firstname, string lastname, float wage }; employee emparray[] = {}; employee value[] = {}; //Code for populating emparray and structure, then determine search field etc. cout << "Enter a search value: "; cin >> value.lastname; for(i = 0; i < 5; i++) { if(strcmp(value.lastname.c_str, emparray[i].lastname.c_str) == 0) { output(); } } Which... I thought would work, but it's giving me the following error.. Error 1 error C3867: 'std::basic_string<_Elem,_Traits,_Alloc>::c_str': function call missing argument list; use '&std::basic_string<_Elem,_Traits,_Alloc>::c_str' to create a pointer to member d:\myfile Any thoughts on what's going on? Is there a way to compare two .name notated strings without totally revamping the program? IF you want to drill me on best practices, please feel free, but also please try to solve my particular problem.

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  • Beautify Integer values for comparing as strings

    - by Zahra
    Hi. For some reason I need to enter my integer values to database as string, then I want to run a query on them and compare those integers as strings. Is there any way to beautify integer numbers (between 1 and 1 US billion as an example) so I can compare them as strings? Thanks in advance.

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  • How do I get characters common to two vectors in C++?

    - by Sam Phelps
    I am trying to compare two vector objects, and return a single vector containing all the chars which appear in both vectors. How would I go about this without writing some horribly complex manual method which compares every char in the first vector to every char in the second vector and using an if to add it to a third vector (which would be returned) if they match. Maybe my lack of real experience with vectors is making me imagine this will be harder than it really is, but I suspect there is some simplier way which I have been unable to find through searching.

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  • c# How to find if two objects are equal

    - by Simon G
    Hi, I'm needing to know the best way to compare two objects and to find out if there equal. I'm overriding both GethashCode and Equals. So a basic class looks like: public class Test { public int Value { get; set; } public string String1 { get; set; } public string String2 { get; set; } public override int GetHashCode() { return Value ^ String1.GetHashCode() ^ String2.GetHashCode(); } public override bool Equals( object obj ) { return GetHashCode() == obj.GetHashCode(); } } So for testing purposes I created two objects: Test t = new Test() { Value = 1, String1 ="One", String2 = "One" }; Test t2 = new Test() { Value = 1, String1 = "Two", String2 = "Two" }; bool areEqual = t.Equals( t2 ); In testing this areEqual returns true event though both objects are different. I realise this is because String1 and String2 are the same value in each object and thus cancels each other out when hashing. Is there a better way off hashing object that the method I have that will resolve my issue?

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  • Quickest way to compare a buch of array or list of values.

    - by zapping
    Can you please let me know on the quickest and efficient way to compare a large set of values. Its like there are a list of parent codes(string) and each code has a series of child values(string). The child lists have to be compared with each other and find out duplicates and count how many times they repeat. code1(code1_value1, code1_value2, code3_value3, ..., code1_valueN); code2(code2_value1, code1_value2, code2_value3, ..., code2_valueN); code3(code2_value1, code3_value2, code3_value3, ..., code3_valueN); . . . codeN(codeN_value1, codeN_value2, codeN_value3, ..., codeN_valueN); The lists are huge say like there are 100 parent codes and each has about 250 values in them. There will not be duplicates within a code list. Doing it in java and the solution i could figure out is. Store the values of first set of code in as codeMap.put(codeValue, duplicateCount). The count initialized to 0. Then compare the rest of the values with this. If its in the map then increment the count otherwise append it to the map. The downfall of this is to get the duplicates. Another iteration needs to be performed on a very large list. An alternative is to maintain another hashmap for duplicates like duplicateCodeMap.put(codeValue, duplicateCount) and change the initial hashmap to codeMap.put(codeValue, codeValue). Speed is what is requirement. Hope one of you can help me with it.

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  • Comparing objects and inheritance

    - by ereOn
    Hi, In my program I have the following class hierarchy: class Base // Base is an abstract class { }; class A : public Base { }; class B : public Base { }; I would like to do the following: foo(const Base& one, const Base& two) { if (one == two) { // Do something } else { // Do something else } } I have issues regarding the operator==() here. Of course comparing an instance A and an instance of B makes no sense but comparing two instances of Base should be possible. (You can't compare a Dog and a Cat however you can compare two Animals) I would like the following results: A == B = false A == A = true or false, depending on the effective value of the two instances B == B = true or false, depending on the effective value of the two instances My question is: is this a good design/idea ? Is this even possible ? What functions should I write/overload ? My apologies if the question is obviously stupid or easy, I have some serious fever right now and my thinking abilities are somewhat limited :/ Thank you.

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  • Efficient and accurate way to compact and compare Python lists?

    - by daveslab
    Hi folks, I'm trying to a somewhat sophisticated diff between individual rows in two CSV files. I need to ensure that a row from one file does not appear in the other file, but I am given no guarantee of the order of the rows in either file. As a starting point, I've been trying to compare the hashes of the string representations of the rows (i.e. Python lists). For example: import csv hashes = [] for row in csv.reader(open('old.csv','rb')): hashes.append( hash(str(row)) ) for row in csv.reader(open('new.csv','rb')): if hash(str(row)) not in hashes: print 'Not found' But this is failing miserably. I am constrained by artificially imposed memory limits that I cannot change, and thusly I went with the hashes instead of storing and comparing the lists directly. Some of the files I am comparing can be hundreds of megabytes in size. Any ideas for a way to accurately compress Python lists so that they can be compared in terms of simple equality to other lists? I.e. a hashing system that actually works? Bonus points: why didn't the above method work?

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  • C#, Fastest (Best?) Method of Identifying Duplicate Files in an Array of Directories

    - by Nate Greenwood
    I want to recurse several directories and find duplicate files between the n number of directories. My knee-jerk idea at this is to have a global hashtable or some other data structure to hold each file I find; then check each subsequent file to determine if it's in the "master" list of files. Obviously, I don't think this would be very efficient and the "there's got to be a better way!" keeps ringing in my brain. Any advice on a better way to handle this situation would be appreciated.

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  • VB.Net HTTPWebRequest Speed is slow comparing Python URLOpen

    - by regexhacks
    Hi I am coding a web-crawler which will crawl the websites and selectively parse different sections of a web site. I am a .Net developer so the choice was obvious that I did it in .Net but the speed was very slow which included downloading and parsing of HTMLPages Then I tried to just download the contents first using .Net and then same domains using python but the python was very impressive in downloading data. I have achieved downloading using python but the later part is not that easy to code in python, which obviously i don't want to do. The same batch of domain which took 100 seconds in Python was taking 20 minutes in .Net based crawler I tried http://www.eqlit.com/ to download and in took 8 seconds in Python and same was taking 100 Seconds in .Net crawler Does anyone anyone have any idea why this is slow in .Net but fast in python?

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  • How to compare DateTime Objects while looping through a list?

    - by Taniq
    I'm trying to loop through a list (csv) containing two fields; a name and a date. There are various duplicated names and various dates in the list. I'm trying to deduce for each name in the list, where there are multiple instances of the same name, which corresponding date is the latest. I realise, from looking at another answer, that I need to use the DateTime.Compare method which is fine, but my problem is working out which date is later. Once I know this I need to produce a file with unique names and the latest date relating to it. This is my first question which makes me a newbie. EDIT: Initially I thought it would be 'ok' to set the LatestDate object to a date that wouldn't show up in my file, therefore making any later dates in the file the LatestDate. Here's my coding so far: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; namespace flybe_overwriter { class Program { static DateTime currentDate; static DateTime latestDate = new DateTime(1000,1,1); static HashSet<string> uniqueNames = new HashSet<string>(); static string indexpath = @"e:\flybe test\indexing.csv"; static string[] indexlist = File.ReadAllLines(indexpath); static StreamWriter outputfile = new StreamWriter(@"e:\flybe test\match.csv"); static void Main(string[] args) { foreach (string entry in indexlist) { uniqueNames.Add(entry.Split(',')[0]); } HashSet<string>.Enumerator fenum = new HashSet<string>.Enumerator(); fenum = uniqueNames.GetEnumerator(); while (fenum.MoveNext()) { string currentName = fenum.Current; foreach (string line in indexlist) { currentDate = new DateTime(Convert.ToInt32(line.Split(',')[1].Substring(4, 4)), Convert.ToInt32(line.Split(',')[1].Substring(2, 2)), Convert.ToInt32(line.Split(',')[1].Substring(0, 2))); if (currentName == line.Split(',')[0]) { if(DateTime.Compare(latestDate.Date, currentDate.Date) < 1) { // Console.WriteLine(currentName + " " + latestDate.ToShortDateString() + " is earlier than " + currentDate.ToShortDateString()); } else if (DateTime.Compare(latestDate.Date, currentDate.Date) > 1) { // Console.WriteLine(currentName + " " + latestDate.ToShortDateString() + " is later than " + currentDate.ToShortDateString()); } else if (DateTime.Compare(latestDate.Date, currentDate.Date) == 0) { // Console.WriteLine(currentName + " " + latestDate.ToShortDateString() + " is the same as " + currentDate.ToShortDateString()); } } } } } } } Any help appreciated. Thanks.

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  • WSDL vs DLL. Which is better?

    - by Lopper
    I would like to create a reusable interface to transfer some proprietary information over the TCP/IP connection. If given only the choice of either WSDL or DLL, what are the pros and cons of using each? This is assuming that Windows OS is used.

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  • Is Linq Faster, Slower or the same?

    - by Vaccano
    Is this: Box boxToFind = AllBoxes.Where(box => box.BoxNumber == boxToMatchTo.BagNumber); Faster or slower than this: Box boxToFind ; foreach (Box box in AllBoxes) { if (box.BoxNumber == boxToMatchTo.BoxNumber) { boxToFind = box; } } Both give me the result I am looking for (boxToFind). This is going to run on a mobile device that I need to be performance conscientious of.

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  • What are provenly scalable data persistence solutions for consumer profiles?

    - by Hubbard
    Consumer profiles with analytical scores [ConsumerID, 1..n demographical variables, 1...n analytical scores e.g. "likely to churn" "likely to buy an item 100$ in worth" etc.] have to be possible to query fast if they are to be used in customizing web-sites, consumer communications etc. Well. If you have: Large number of consumers Large profiles with a huge set of variables (as profiles describing human behaviour are likely to be..) ...you are in trouble. If you really have a physical relational database to which you target a query and then a physical disk starts to rotate someplace to give you an individual profile or a set of profiles, the profile user (a web site customizing a page, a recommendation engine making a recommendation..) has died of boredom before getting any observable results. There is the possibility of having the profiles in memory, which would of course increase the performance hugely. What are the most proven solutions for a fast-response, scalable consumer profile storage? Is there a shootout of these someplace?

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  • How do I compare vectors in C++?

    - by Sam Phelps
    I am trying to compare two vector objects, and return a single vector containing all the chars which appear in both vectors. How would I go about this without writing some horribly complex manual method which compares every char in the first vector to every char in the second vector and using an if to add it to a third vector (which would be returned) if they match. Maybe my lack of real experience with vectors is making me imagine this will be harder than it really is, but I suspect there is some simplier way which I have been unable to find through searching.

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  • Tree data structure gems compared?

    - by huug
    I want to you use a tree structure for my navigation. I was thinking about using Ancestry, but then I found this article about 7 plugins for providing a tree structure to your models. What are the pros/cons for each plugin/gem and above all: which one do you recommend? Tnx!

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  • Why does Ordered[A] use a compare method instead of reusing compareTo?

    - by soc
    trait Ordered[A] extends java.lang.Comparable[A] { def compare(that: A): Int def < (that: A): Boolean = (this compare that) < 0 def > (that: A): Boolean = (this compare that) > 0 def <= (that: A): Boolean = (this compare that) <= 0 def >= (that: A): Boolean = (this compare that) >= 0 def compareTo(that: A): Int = compare(that) } Isn't it a bit useless to have both compare and compareTo? What is the huge benefit I'm missing here? If they had just used compareTo I could just had replaced Comparable with Ordered in my code and be done.

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  • Spring 3, Java EE 6

    - by arg20
    I'm learning Java EE 6. I've seen how much progress it has achieved in this release of the umbrella specification. EJBs 3.1 are far easier and more lightweight than previous versions, and CDI is amazing. I'm not familiar with Spring, but I often read that it offered some neat features that the Java EE stack didn't. Yet I also read now that JEE has caught up, and can now fully compete with Spring. I know that choosing from both depends on many factors, but if we only focus on features, say the latest trends etc. Which one has the leading edge?. Can Spring 3 offer some assets The JAVA EE 6 stack can't? Also, what about Seam framework? From what I read it's like java ee 6 but with some additions?

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  • Python 3 order of testing undetermined

    - by user578598
    string='a' p=0 while (p <len(string)) & (string[p]!='c') : p +=1 print ('the end but the process already died ') while (p <1) & (string[p]!='c') : IndexError: string index out of range I want to test a condition up to the end of a string (example string length=1) why are both parts of the and executed is the condition is already false! as long as p < len(string). the second part does not even need executing. if it does a lot of performance can be lost

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  • How can I use Perl to determine whether the contents of two files are identical?

    - by Zaid
    This question comes from a need to ensure that changes I've made to code doesn't affect the values it outputs to text file. Ideally, I'd roll a sub to take in two filenames and return 1or return 0 depending on whether the contents are identical or not, whitespaces and all. Given that text-processing is Perl's forté, it should be quite easy to compare two files and determine whether they are identical or not (code below untested). use strict; use warnings; sub files_match { my ( $fileA, $fileB ) = @_; open my $file1, '<', $fileA; open my $file2, '<', $fileB; while (my $lineA = <$file1>) { next if $lineA eq <$file2>; return 0 and last; } return 1; } The only way I can think of (sans CPAN modules) is to open the two files in question, and read them in line-by-line until a difference is found. If no difference is found, the files must be identical. But this approach is limited and clumsy. What if the total lines differ in the two files? Should I open and close to determine line count, then re-open to scan the texts? Yuck. I don't see anything in perlfaq5 relating to this. I want to stay away from modules unless they come with the core Perl 5.6.1 distribution.

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