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  • Select only the first rows for each unique value of a column in R

    - by dmvianna
    From a dataframe like this test <- data.frame('id'= rep(1:5,2), 'string'= LETTERS[1:10]) test <- test[order(test$id), ] rownames(test) <- 1:10 > test id string 1 1 A 2 1 F 3 2 B 4 2 G 5 3 C 6 3 H 7 4 D 8 4 I 9 5 E 10 5 J I want to create a new one with the first appearance of each id / string pair. If sqldf accepted R code within it, the query could look like this: res <- sqldf("select id, min(rownames(test)), string from test group by id, string") > res id string 1 1 A 3 2 B 5 3 C 7 4 D 9 5 E Is there a solution short of creating a new column like test$row <- rownames(test) and running the same sqldf query with min(row)?

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  • How to create unique user key

    - by Grayson Mitchell
    Scenario: I have a fairly generic table (Data), that has an identity column. The data in this table is grouped (lets say by city). The users need an identifier in order for printing on paper forms, etc. The users can only access their cites data, so if they use the identity column for this purpose they will see odd numbers (e.g. a 'New York' user might see 1,37,2028... as the listed keys. Idealy they would see 1,2,3... (or something similar) The problem of course is concurrency, this being a web application you can't just have something like: UserId = Select Count(*)+1 from Data Where City='New York' Has anyone come up with any cunning ways around this problem?

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  • How to use Groovy Set for unique elements?

    - by Guy
    As simple as this must be I still can't understand where am I wrong: class A { boolean equals(o) { true } } def s = [new A(), new A()] as Set assert s.size() == 1 // Assertion failed: actually gives 2 Which method should I override in order to get uniqueness?

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  • How to get unique value in jquery?

    - by jquerier
    I am learning jquery. I have following chunk of code in a html file: <table width="100%"> <tr> <td align='center'> <div> <a id='get_this' href='#'> <input type='hidden' id='id' value='1'><img src='images/1.gif'></a> </div> </td> <td align='center'> <div> <a id='get_this' href='#'> <input type='hidden' id='id' value='2'><img src='images/2.gif'></a> </div> </td> <td align='center'> <div> <a id='get_this' href='#'> <input type='hidden' id='id' value='3'><img src='images/3.gif'></a> </div> </td> </tr> What I want to do is, when I click any of the image, I can get the value, so that I can display the information. For example, I click the id=1, then I will display information on id1 in somewhere else. I tried this: $("a#get_this").click(function(){ var id = $('input[type=hidden]#id').val(); window.alert("You have chosen the id: " + id); }); It always return id: 1 to me.

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  • Remove a single non-unique value from a sequence in F#

    - by mavnn
    I have a sequence of integers representing dice in F#. In the game in question, the player has a pool of dice and can choose to play one (governed by certain rules) and keep the rest. If, for example, a player rolls a 6, 6 and a 4 and decides to play one the sixes, is there a simple way to return a sequence with only one 6 removed? Seq.filter (fun x -> x != 6) dice removes all of the sixes, not just one.

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  • mysql query to get unique value from one column

    - by vesselyp
    i have a table named locations of which i want to select and get values in such a way that it should select only distinct values from a column but select all other values . table name: locations column names 1: country values : America, India, India, India column names 2: state/Province : Newyork, Punjab, Karnataka, kerala when i select i should get India only once and all the three states listed under India . is ther any way..??? sombody please help

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  • Selecting unique elements using XSLT.

    - by AJ
    I have the following XML: <option> <title>ABC</title> <desc>123</desc> </option> <option> <title>ABC</title> <desc>12345</desc> </option> <option> <title>ABC</title> <desc>123</desc> </option> <option> <title>EFG</title> <desc>123</desc> </option> <option> <title>EFG</title> <desc>456</desc> </option> Using XSLT, I want to transform it into: <choice> <title>ABC</title> <desc>123</desc> <desc>12345</desc> </choice> <choice> <title>EFG</title> <desc>123</desc> <desc>456</desc> </choice>

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  • Print unique ascii characters in eclipse console

    - by Shaded
    Hey guys, Kind of a strange question but... here it goes. Recently my application threw an IOException that the text only had a clubs symbol in it (like the suit in cards) I know this is probably because there was a number in there that was cast to a char and printed to the screen, and I've found where that might have happened. The only problem is, I can't recreate it in eclipse because the eclipse console doesn't want to print those characters for me. All I get are boxes. I figure this is an encoding issue or something but I need eclipse to print out those characters just like the windows console would. Is there a setting I can change to do this?

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  • Create unique links for indvidual elements of a PHP generated table

    - by typoknig
    I have a table generated from some PHP code that lists a SMALL amount of important information for employees. I want to make it so each row, or at least one element in each row can be clicked on so the user will be redirected to ALL of the information (pulled from MySQL database) related to the employee who was clicked on. I am not sure how would be the best way to go about this, but I am open to suggestions. I would like to stick to PHP and/or JavaScript. Below is the code for my table: <table> <tr> <td id="content_heading" width="25px">ID</td> <td id="content_heading" width="150px">Last Name</td> <td id="content_heading" width="150px">First Name</td> <td id="content_heading" width="75px">SSN</td> </tr> <?php $user = 'user'; $pass = 'pass'; $server = 'localhost'; $link = mysql_connect($server, $user, $pass); if (!$link){ die('Could not connect to database!' . mysql_error()); } mysql_select_db('mydb', $link); $query = "SELECT * FROM employees"; $result = mysql_query($query); mysql_close($link); $num = mysql_num_rows($result); for ($i = 0; $i < $num; $i++){ $row = mysql_fetch_array($result); $class = (($i % 2) == 0) ? "table_odd_row" : "table_even_row"; echo "<tr class=".$class.">"; echo "<td>".$row[id]."</td>"; echo "<td>".$row[l_name]."</td>"; echo "<td>".$row[f_name]."</td>"; echo "<td>".$row[ssn]."</td>"; echo "</tr>"; } ?> </table>

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  • Unique identification string in php

    - by NardCake
    Currently me and my friend are developing a website, for what we will call 'projects' we just have a basic auto increment id in the database used to navigate to projects such as oururl.com/viewproject?id=1 but we started thinking, if we have alot of posted projects thats going to be a LONG url. So we need to somehow randomly generate a alphanumerical string about 6 characters long. We want the chance of the string being duplicated being extremely low and of course we will query the database before assigning an identifier. Thanks for anyhelp, means alot!

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  • Finding object count where a field is unique in Django

    - by Johnd
    I have a model that is something like this: class Input(models.Model): details = models.CharField(max_length=1000) user = models.ForeignKey(User) class Case(Input): title = models.CharField(max_length=200) views = models.IntegerField() class Argument(Input): case = models.ForeignKey(Case) side = models.BooleanField() A user can submit many arguments, per case. I want to be able to say how many users have submitted side=true arguments. I mean if 1 user had 10 arguments and another user had 2 arguments (both side=true) I'd want the count to be 2, not 12.

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  • only return random number when it is unique

    - by phil
    My brain is melting today and i cannot think how to do this simple bit of code. numberList is a string of numbers seperated by commas like '2, 34, 10' etc.. when i request a random number i need to check if the string has the number, if it does i want to keep requesting a random number until the random number is definitely not in the string. i cant think what kind of loop i would do to get this to work: Random r = new Random(); public int RandomPos(int max) { int i; do { i = r.Next(max) + 1; } while (!numberList.Contains(i.ToString())); return i; }

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  • Counting unique XML element attributes using XSLT

    - by patrick_corrigan
    I've just started using XSLT and am trying to figure this out. Your help would be greatly appreciated. Example XML file <purchases> <item id = "1" customer_id = "5"> </item> <item id = "2" customer_id = "5"> </item> <item id = "7" customer_id = "4"> </item> </purchases> Desired HTML Output: <table> <tr><th>Customer ID</th><th>Number of Items Purchased</th></tr> <tr><td>5</td><td>2</td></tr> <tr><td>4</td><td>1</td></tr> </table> Customer with id number 5 has bought 2 items. Customer with id number 4 has bought 1 item.

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  • Loop through different sets of unique permutations

    - by user558610
    Hi I'm having a hard time getting started to layout code for this problem. I have a fixed amount of random numbers, in this case 8 numbers. R[] = { 1, 2, 3, 4, 5, 6, 7, 8 }; That are going to be placed in 3 sets of numbers, with the only constraint that each set contain minimum one value, and each value can only be used once. For example: R1[] = { 1, 4 } R2[] = { 2, 8, 5, 6 } R3[] = { 7, 4 } I need to loop through all possible combinations of a set R1, R2, R3. Order is not important, so if the above example happened, I don't need R1[] = { 4, 1 } R2[] = { 2, 8, 5, 6 } R3[] = { 7, 4 } NOR R1[] = { 2, 8, 5, 6 } R2[] = { 7, 4 } R3[] = { 1, 4 } What is a good method?

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  • Calculate sum of objects for each unique object property in Ruby

    - by macek
    I was helping with an answer in this question and it sparked a question of my own. Pie is an object that has a pieces array made of of PiePiece objects. Each PiePiece has a flavor attribute How do I create a hash that looks like this: # flavor => number of pieces { :cherry => 3 :apple => 1 :strawberry => 2 } This works, but I think it could be improved def inventory hash = {} pieces.each do |p| hash[p.flavor] ||= 0 hash[p.flavor] += 1 end hash end Any ideas?

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  • Many Buttons on a Page, Need to send back Unique Post Data with each

    - by CoffeeAddict
    I'm listing out a bunch of cars with a button next to them that when clicked will need to perform a GET but also sends over that item's model.Name: @using (Html.BeginForm("GetCarUrl", "Car", FormMethod.Get, new { model = Model })) { if(Model.Cars != null && Model.Cars.Count > 0) { foreach (CarContent car in Model.Cars) { <p>@car.Name</p> } <input type="button" value="Get Car Url" class="submit" /> } So the page renders a bunch of hyperlinks and buttons: [hyperlink1] [submit] [hyperlink2] [submit] [hyperlink3] [submit] [hyperlink4] [submit] [hyperlink5] [submit] ... When a user clicks on any of the submits, I need to pass back its corresponding @car.CarType for that specific hyperlink Not sure how to go about this. My action method expects a @car.CarType for that specific car hyperlink to be sent to it

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  • Trouble move-capturing std::unique_ptr in a lambda using std::bind

    - by user2478832
    I'd like to capture a variable of type std::vector<std::unique_ptr<MyClass>> in a lambda expression (in other words, "capture by move"). I found a solution which uses std::bind to capture unique_ptr (http://stackoverflow.com/a/12744730/2478832) and decided to use it as a starting point. However, the most simplified version of the proposed code I could get doesn't compile (lots of template mistakes, it seems to try to call unique_ptr's copy constructor). #include <functional> #include <memory> std::function<void ()> a(std::unique_ptr<int>&& param) { return std::bind( [] (int* p) {}, std::move(param)); } int main() { a(std::unique_ptr<int>(new int())); } Can anybody point out what is wrong with this code? EDIT: tried changing the lambda to take a reference to unique_ptr, it still doesn't compile. #include <functional> #include <memory> std::function<void ()> a(std::unique_ptr<int>&& param) { return std::bind( [] (std::unique_ptr<int>& p) {}, // also as a const reference std::move(param)); } int main() { a(std::unique_ptr<int>(new int())); }

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  • MS SQL Return 1 Row Per Boat

    - by Tyler
    Basically, what I want to do is join 4 tables together and return 1 row for each boat. Table Layouts [Boats] id, date, section, raft [Photos] id, boatid, pthurl, purl [River_Company] id, sort, company, company_short [River_Section] id, section Its very simple as far as structure, however, I've having the time of my life trying to get it to return only 1 row. No boat will ever be on the same day, the only thing that's messing this up is the photo table. If you know a better way for it to return the record table for all the boats boats and only 1 photo from the photo table, please, please post it!!

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  • php array_unique

    - by dotty
    HAy, i have an array Array( [0] => Array ( [0] => 33 [user_id] => 33 [1] => 3 [frame_id] => 3 ) [1] => Array ( [0] => 33 [user_id] => 33 [1] => 3 [frame_id] => 3 ) [2] => Array ( [0] => 33 [user_id] => 33 [1] => 8 [frame_id] => 8 ) [3] => Array ( [0] => 33 [user_id] => 33 [1] => 3 [frame_id] => 3 ) [4] => Array ( [0] => 33 [user_id] => 33 [1] => 3 [frame_id] => 3 ) ) As you can see key 0 is the same as 1,3 and 4. And key 2 is different from them all. When running the array_unique function on them, the only left is Array ( [0] => Array ( [0] => 33 [user_id] => 33 [1] => 3 [frame_id] => 3 ) ) any ideas why array_unique isn't working as expected?

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  • So can unique_ptr be used safely in stl collections?

    - by DanDan
    I am confused with unique_ptr and rvalue move philosophy. Let's say we have two collections: std::vector<std::auto_ptr<int>> autoCollection; std::vector<std::unique_ptr<int>> uniqueCollection; Now I would expect the following to fail, as there is no telling what the algorithm is doing internally and maybe making internal pivot copies and the like, thus ripping away ownership from the auto_ptr: std::sort(autoCollection.begin(), autoCollection.end()); I get this. And the compiler rightly disallows this happening. But then I do this: std::sort(uniqueCollection.begin(), uniqueCollection.end()); And this compiles. And I do not understand why. I did not think unique_ptrs could be copied. Does this mean a pivot value cannot be taken, so the sort is less efficient? Or is this pivot actually a move, which in fact is as dangerous as the collection of auto_ptrs, and should be disallowed by the compiler? I think I am missing some crucial piece of information, so I eagerly await someone to supply me with the aha! moment.

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  • C# dictionary uniqueness for sibling classes using IEquatable<T>

    - by anthony
    I would like to store insances of two classes in a dictionary structure and use IEquatable to determine uniqueness of these instances. Both of these classes share an (abstract) base class. Consider the following classes: abstract class Foo { ... } class SubFoo1 : Foo { ... } class SubFoo2 : Foo { ... } The dictionary will be delcared: Dictionary<Foo, Bar> Which classes should be declared as IEquatable? And what should the generic type T be for those declarations? Is this even possible?

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  • How can I get this code involving unique_ptr to compile?!

    - by Neil G
    #include <vector> #include <memory> using namespace std; class A { public: A(): i(new int) {} A(A const& a) = delete; A(A &&a): i(move(a.i)) {} unique_ptr<int> i; }; class AGroup { public: void AddA(A &&a) { a_.emplace_back(move(a)); } vector<A> a_; }; int main() { AGroup ag; ag.AddA(A()); return 0; } does not compile... (says that unique_ptr's copy constructor is deleted) I tried replacing move with forward. Not sure if I did it right, but it didn't work for me.

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  • Validate uniqueness within a recent set

    - by Matchu
    Is there a standard Rails 3 way of detecting uniqueness within a particular scope, or is this custom validation all I can do? class Post < ActiveRecord::Base # [named scope for recent posts] validates do |post| if Post.recent.where('url = ?', post.url).count > 0 errors[:url] = 'has already been posted recently - thanks anyway!' end end end (Haven't yet tried that exact code, so there may be errors, but you get the idea.)

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