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  • Problem with initializing a hash in ruby

    - by Cyborgo
    Hi, I have a text file from which I want to create a Hash for faster access. My text file is of format (space delimited) author title date popularity I want to create a hash in which author is the key and the remaining is the value as an array. created_hash["briggs"] = ["Manup", "Jun,2007", 10] Thanks in advance.

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  • List comprehension, map, and numpy.vectorize performance

    - by mcstrother
    I have a function foo(i) that takes an integer and takes a significant amount of time to execute. Will there be a significant performance difference between any of the following ways of initializing a: a = [foo(i) for i in xrange(100)] a = map(foo, range(100)) vfoo = numpy.vectorize(foo) a = vfoo(range(100)) (I don't care whether the output is a list or a numpy array.) Is there a better way?

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  • Confusion over C++ new operator and classes

    - by Nils
    Hi all I created a simple class in C++ which has a private dynamic array. In the constructor I initialize the array using new and in the destructor I free it using delete. When I instantiate the class using Class a = Class(..); it works as expected, however it seems I cannot instantiate it using the new operator (Like Class *a = new Class(..);), I always get a segmentation fault. What I don't understand is when I should use new to instantiate a class and when just call the constructor or should it be possible to instantiate a class either with new or by just calling the constructor. float** A = new float*[3]; for (int i=0; i<3; i++) { A[i] = new float[3]; } A[0][0] = 3; A[0][1] = 3; A[0][2] = 4; A[1][0] = 5; A[1][1] = 6; A[1][2] = 7; A[2][0] = 1; A[2][1] = 2; A[2][2] = 3; Matrix *M = new Matrix(A, 3, 3); delete[] A; delete M; Below the class definition.. class Matrix { private: int width; int height; int stride; float* elements; public: Matrix(float** a, int n, int m); ~Matrix(); }; Matrix::Matrix(float** a, int n, int m) { // n: num rows // m: elem per rows elements = new float[n*m]; for (int i=0; i<n; i++) { for (int j=0; j<m; j++) { elements[i*n + j] = a[n][m]; } } } Matrix::~Matrix() { delete[] elements; }

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  • How do you label output variables in an IDL FOR loop for further processing outside the loop in the same program?

    - by user610769
    I have a FOR loop like this: FOR k = 1,216 DO atom = G[,0::(215+k)] END What I would like to be able to do is to store in memory the array for each atom, say, atom_k and then call these different variables to perform further operations outside the FOR loop. Conceptually, I want to label the "atom" variable with the "k" counter somewhat like this: FOR k = 1,216 DO atom(k) = G[,0::(215+k)] END Of course, this doesn't work because "k" is no longer a label in this case. Does anyone know?

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  • Air/Flex concatenating a variable with a property

    - by Deyon
    I have three text boxes on the stage id=red, blue, green same as the keys in my cars Object/Array public function carsToBox():void { var cars:Object={red:"300zx",blue:"Skyline",green:"Supra"}; for(var tempObj:String in cars) { tempObj.text= cars[tempObj];//this trows errors } } So I'm thinking "tempObj.text" would equal red.text but I can't stick "tempObj" with ".text" is there a way this can be done?

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  • get data using junction table with linq-sql confused :$

    - by raklos
    Im using linq-sql .I have 3 tables. e.g Project, People and a ProjectsPeople(fk's ProjectID and PeopleID) (junction) Table. given a set of peopleIDArray (an array of ints as people ID's) how can i get only Projects that have atleast one of the peopleId's associated with them? i.e there will be atleast one (may be more) record in the ProjectsPeople table that will have a ProjectId and an id from the peopleIDArray ) thanks

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  • read lenght of string from stdin

    - by teoz
    I want to take a string from stdin but I don't want a static array of fixed size i knew that scanf need something where save the stdin input, but i can't do something like this: char string[10] scanf("%s",string); becouse i need to knew before how long will be the string in order to allocate the right memory space can you help me to resolve this problem?

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  • memcached vs. internal caching in PHP?

    - by waitinforatrain
    Hey, I'm working on some old(ish) software in PHP that maintains a $cache array to reduce the number of SQL queries. I was thinking of just putting memcached in its place and I'm wondering whether or not to get rid of the internal caching. Would there still be a worthwihle performance increase if I keep the internal caching, or would memcached suffice?

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  • PHP - not sure how to ask - regarding variables and $_POST

    - by Phil
    I have a PHP form. The form works but I'm trying to test to see if a value other than the first item has been selected. I can't figure out how to write the If statement. $products = array( '' => 1, 'Item 2' => 2, 'Item 3' => 3, 'Item 4' => 4, 'Item 5' => 5, 'Item 6' => 6 ); $html = generateSelect('products', $products); function generateSelect($name = '', $options = array()) { $html = '<select name="'.$name.'">'; foreach ($options as $option => $value) { $html .= '<option value='.$value.'>'.$option.'</option>'; } $html .= '</select>'; return $html; } In my table, the drop down box is displayed: <tr> <td style="width:{$left_col_width}; text-align:left; vertical-align:center; padding:{$cell_padding}; font-weight:bold; {$product[3]}">{$product[0]}</td> <td style="text-align:left; vertical-align:top; padding:{$cell_padding};"><select name="{$product[1]}"> <option value="1"></option> <option value="2">Item 2</option> <option value="3">Item 3</option> <option value="4">Item 4</option> <option value="5">Item 5</option> <option value="6">Item 6</option> </select></td> </tr> I use the following if statement to check to see if someone has entered a phone number. if they have not entered a phone number, then the "Phone:" text turns red. How do I do an if statement similar to this to verify that someone has selected a product option from the drop down box? if(!empty($_POST['phone'])) { $phone[2] = clean_var($_POST['phone']); if (function_exists('htmlspecialchars')) $phone[2] = htmlspecialchars($phone[2], ENT_QUOTES); } else { $error = 1; $phone[3] = 'color:#d20128;'; } it seems simple but I can't figure it out.

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  • How to find same-value rectangular areas of a given size in a matrix most efficiently?

    - by neo
    My problem is very simple but I haven't found an efficient implementation yet. Suppose there is a matrix A like this: 0 0 0 0 0 0 0 4 4 2 2 2 0 0 4 4 2 2 2 0 0 0 0 2 2 2 1 1 0 0 0 0 0 1 1 Now I want to find all starting positions of rectangular areas in this matrix which have a given size. An area is a subset of A where all numbers are the same. Let's say width=2 and height=3. There are 3 areas which have this size: 2 2 2 2 0 0 2 2 2 2 0 0 2 2 2 2 0 0 The result of the function call would be a list of starting positions (x,y starting with 0) of those areas. List((2,1),(3,1),(5,0)) The following is my current implementation. "Areas" are called "surfaces" here. case class Dimension2D(width: Int, height: Int) case class Position2D(x: Int, y: Int) def findFlatSurfaces(matrix: Array[Array[Int]], surfaceSize: Dimension2D): List[Position2D] = { val matrixWidth = matrix.length val matrixHeight = matrix(0).length var resultPositions: List[Position2D] = Nil for (y <- 0 to matrixHeight - surfaceSize.height) { var x = 0 while (x <= matrixWidth - surfaceSize.width) { val topLeft = matrix(x)(y) val topRight = matrix(x + surfaceSize.width - 1)(y) val bottomLeft = matrix(x)(y + surfaceSize.height - 1) val bottomRight = matrix(x + surfaceSize.width - 1)(y + surfaceSize.height - 1) // investigate further if corners are equal if (topLeft == bottomLeft && topLeft == topRight && topLeft == bottomRight) { breakable { for (sx <- x until x + surfaceSize.width; sy <- y until y + surfaceSize.height) { if (matrix(sx)(sy) != topLeft) { x = if (x == sx) sx + 1 else sx break } } // found one! resultPositions ::= Position2D(x, y) x += 1 } } else if (topRight != bottomRight) { // can skip x a bit as there won't be a valid match in current row in this area x += surfaceSize.width } else { x += 1 } } } return resultPositions } I already tried to include some optimizations in it but I am sure that there are far better solutions. Is there a matlab function existing for it which I could port? I'm also wondering whether this problem has its own name as I didn't exactly know what to google for. Thanks for thinking about it! I'm excited to see your proposals or solutions :)

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  • UITabBarController not showing all view controllers

    - by rounak
    My UITabBarcontroller has two view controllers -Favorites -Keypad I add these two controllers in an array in the order Favorites,Keypad,nil. When the app is launched only the Favorites tab appears in the tabbar, I have to click the second tab for the "Keypad" (Title of the viewController) text to appear on the tabbar. How do I make the tabbar have the title of both the view controllers at startup itself?

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  • cakePHP, multiple hasOne in a single model

    - by jason
    say you have 3 models : user, hair_color, and eye_color user hasOne hair_color user also hasOne eye_color however var $hasOne = 'hair_color'; var $hasOne = 'eye_color'; obviously wont work. So how do you implement many hasOne relationships in a single model? I assume the answer is in the cookbook, Im going over that area now, I suspect it has something to do with passing an array to $hasOne, but no example of doing this.

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  • apache mod_rewrite making permanent url problem

    - by Yc Zhang
    In file .htaccess <IfModule mod_rewrite.c> RewriteEngine on RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^\/*get_post\/(.*)$ get_post.php?slug=$0 [L] </IfModule> If I type http://example.com/get_post/abcde, I get an empty array of $_GET variable. How can I achieve the effect like this: http://example.com/get_post?slug=abcde

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  • A question about matrix manipulation

    - by appi
    Given a 1*N matrix or an array, how do I find the first 4 elements which have the same value and then store the index for those elements? PS: I'm just curious. What if we want to find the first 4 elements whose value differences are within a certain range, say below 2? For example, M=[10,15,14.5,9,15.1,8.5,15.5,9.5], the elements I'm looking for will be 15,14.5,15.1,15.5 and the indices will be 2,3,5,7.

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  • Hibernate Native Query problem with named parameters

    - by dime
    I have a problem with Hibernate Native Query. I have one SELECT that selects array slice (PostgreSQL database). The problem is that hibernate recognizes the following part: ":300" from "SELECT my_array[1:300]..." as named parameter and I get the following exception: Not all named parameters have been set. I tried to escape the colon (:) with '\:' , '::' but with no success. The Hibernate version is 3.2

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  • Circular increment: Which is "better"?

    - by Helper Method
    When you have a circular buffer represented as an array, and you need the index to wraparound (i.e., when you reach the highest possible index and increment it), is it "better" to: return (i++ == buffer.length) ? 0: i; Or return i++ % buffer.length; Has using the modulo operator any drawbacks? Is it less readable than the first solution?

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  • Change UITableView Cell Image using IF Statement?

    - by Graeme
    I want to add an image using the cell.imageView setImage: method. However, depending on field from an array (in the form of an NSString and called using [dog types]) I need the image to change to an image which reflects the type of dog. How do I go about doing this? Thanks.

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  • How to apply a function to a collection of elements

    - by Cue
    Consider I have an array of elements out of which I want to create a new 'iterable' which on every next applies a custom 'transformation'. What's the proper way of doing it under python 2.x? For people familiar with Java, the equivalent is Iterables#transform from google's collections framework.

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