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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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  • 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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  • 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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  • Database design question

    - by Lijo
    Hi Team, I have an interesting database design problem that I formulated while travelling by a bus, coming back from my home. Design a normalized database for a bus ticketing system (not reservation system). In each trip, the conductor of the bus will give tickets to its passengers after collecting fare from them. Passengers travel from a various source places to various destination places. The system must be able to give a report of the places for which the number of passengers was more than 2. Suppose the stops for the bus are L1,L2, L3 and L4 Suppose passenger P1 travels from L1 to L4. P2 travels from L2 to L4. P3 travels from L3 to L4. The report should list only (L3-L4) for which it has more than 2 travelers. Can you please help me to solve the following problems 1) Design a normalized database 2) Write a query for the report 3) Is there any site that gives these kinds of interesting database design questions and answers? Thanks Lijo

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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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  • Populate JOIN into a list in one database query

    - by axio
    I am trying to get the records from the 'many' table of a one-to-many relationship and add them as a list to the relevant record from the 'one' table. I am also trying to do this in a single database request. Code derived from http://stackoverflow.com/questions/1580199/linq-to-sql-populate-join-result-into-a-list almost achieves the intended result, but makes one database request per entry in the 'one' table which is unacceptable. That failing code is here: var res = from variable in _dc.GetTable<VARIABLE>() select new { x = variable, y = variable.VARIABLE_VALUEs }; However if I do a similar query but loop through all the results, then only a single database request is made. This code achieves all goals: var res = from variable in _dc.GetTable<VARIABLE>() select variable; List<GDO.Variable> output = new List<GDO.Variable>(); foreach (var v2 in res) { List<GDO.VariableValue> values = new List<GDO.VariableValue>(); foreach (var vv in v2.VARIABLE_VALUEs) { values.Add(VariableValue.EntityToGDO(vv)); } output.Add(EntityToGDO(v2)); output[output.Count - 1].VariableValues = values; } However the latter code is ugly as hell, and it really feels like something that should be do-able in a single linq query. So, how can this be done in a single linq query that makes only a single database query? In both cases the table is set to preload using the following code: _dc = _db.CreateLinqDataContext(); var loadOptions = new DataLoadOptions(); loadOptions.LoadWith<VARIABLE>(v => v.VARIABLE_VALUEs); _dc.LoadOptions = loadOptions; I am using .NET 3.5, and the database back-end was generated using SqlMetal.

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  • Store database, good pattern for simultaneous access

    - by dygi
    I am kinda new to database designing so i ask for some advices or some kind of a good pattern. The situation is that, there is one database, few tables and many users. How should i design the database, or / and which types of queries should i use, to make it work, if users can interact with the database simultaneously? I mean, they have access to and can change the same set of data. I was thinking about transactions, but I am not sure, if that is the right / good / the only solution. I will appreciate some google keywords too.

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  • Android vs iPhone

    - by Moshe
    I know iPhone development fairly well. From personal experience, how hard would it be for me to get into Android. I am concerned less about code than I am about distribution of my software, given the fragmentation of the Android OS on compatible devices.

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  • Number of elements in Python Set

    - by Tim
    I have a list of phone numbers that have been dialed (nums_dialed). I also have a set of phone numbers which are the number in a client's office (client_nums) How do I efficiently figure out how many times I've called a particular client (total) For example: >>>nums_dialed=[1,2,2,3,3] >>>client_nums=set([2,3]) >>>??? total=4 Problem is that I have a large-ish dataset: len(client_nums) ~ 10^5; and len(nums_dialed) ~10^3.

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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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  • Looping Through Database Query

    - by DrakeNET
    I am creating a very simple script. The purpose of the script is to pull a question from the database and display all answers associated with that particular question. We are dealing with two tables here and there is a foreign key from the question database to the answer database so answers are associated with questions. Hope that is enough explanation. Here is my code. I was wondering if this is the most efficient way to complete this or is there an easier way? <html> <head> <title>Advise Me</title> <head> <body> <h1>Today's Question</h1> <?php //Establish connection to database require_once('config.php'); require_once('open_connection.php'); //Pull the "active" question from the database $todays_question = mysql_query("SELECT name, question FROM approvedQuestions WHERE status = active") or die(mysql_error()); //Variable to hold $todays_question aQID $questionID = mysql_query("SELECT commentID FROM approvedQuestions WHERE status = active") or die(mysql_error()); //Print today's question echo $todays_question; //Print comments associated with today's question $sql = "SELECT commentID FROM approvedQuestions WHERE status = active"; $result_set = mysql_query($sql); $result_num = mysql_numrows($result_set); for ($a = 0; $a < $result_num; $a++) { echo $sql; } ?> </body> </html>

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  • Menu MouseOver Image & Image Description Dsiplay from SQL Database

    - by Julu
    Hello, I don't know if this is the right place to post this but here I go. I'm working on a project as a student for my internship and I need help. I have a masterPage with horizontal menu items as shown in the attached screen-captured. What I want to achieved is: Have a default image and description from SQL server database When a user mouse-over the menu item, display an image from a SQL server database and it description based on the mouse-over menu item. When user mouse-out, display default image and description from sql database. I have a also created user interface for inserting images to the database. How do I go about displaying the image and its description based on menu item is my main issue. Here is the link to the screen-captured. http://tinyurl.com/y4p3p32 Thanks a million time

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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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  • Database design for business numbers

    - by Rob Morris
    I'm in need of some help, I need to store the information below into a database, what would the relational database structure be for this: Then I need to create a dropdown for the insurance company followed by another dropdown depending on what the first dropdown selected value was, then once both selects have been chosen display the relevant telephone number. I guess i need to query the database, then display the dropdowns using javascript(jquery) or Ajax?

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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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  • Python - alternative to list.remove(x)?

    - by Seafoid
    Hi, I wish to compare two lists. Generally this is not a problem as I usually use a nested for loop and append the intersection to a new list. In this case, I need to delete the intersection of A and B from A. A = [['ab', 'cd', 'ef', '0', '567'], ['ghy5'], ['pop', 'eye']] B = [['ab'], ['hi'], ['op'], ['ej']] My objective is to compare A and B and delete A intersection B from A, i.e., delete A[0][0] in this case. I tried: def match(): for i in A: for j in i: for k in B: for v in k: if j == v: A.remove(j) list.remove(x) throws a ValueError.

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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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