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  • Is there a way to define a List<> of two elements string array?

    - by Alexander Prokofyev
    I want to build two-dimentional array of strings where length of one dimention is 2. Similar to this string[,] array = new string[,] { {"a", "b"}, {"c", "d"}, {"e", "f"}, {"g", "h"} } Doing List<string[]> list = new List<string[]>(); list.Add(new string[2] {"a", "b"}); list.Add(new string[2] {"c", "d"}); list.Add(new string[2] {"e", "f"}); list.Add(new string[2] {"g", "h"}); list.ToArray(); gives me string[][] but not string[,] array. Just curious, is there some trick to build dynamically string[,] array somehow?

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  • Efficiently compute the row sums of a 3d array in R

    - by Gavin Simpson
    Consider the array a: > a <- array(c(1:9, 1:9), c(3,3,2)) > a , , 1 [,1] [,2] [,3] [1,] 1 4 7 [2,] 2 5 8 [3,] 3 6 9 , , 2 [,1] [,2] [,3] [1,] 1 4 7 [2,] 2 5 8 [3,] 3 6 9 How do we efficiently compute the row sums of the matrices indexed by the third dimension, such that the result is: [,1] [,2] [1,] 12 12 [2,] 15 15 [3,] 18 18 ?? The column sums are easy via the 'dims' argument of colSums(): > colSums(a, dims = 1) but I cannot find a way to use rowSums() on the array to achieve the desired result, as it has a different interpretation of 'dims' to that of colSums(). It is simple to compute the desired row sums using: > apply(a, 3, rowSums) [,1] [,2] [1,] 12 12 [2,] 15 15 [3,] 18 18 but that is just hiding the loop. Are there other efficient, truly vectorised, ways of computing the required row sums?

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  • Do applescript repeat loops reflect changes instantly?

    - by user1159454
    I'm making a script to open multiple folders in a directory, and it's not working as planned. I've tried outlining it and walking through the steps one by one pretending I'm the computer executing it but when I run it the outcome is very different. It uses repeat and repeat with a lot. The repeat repeats for as long as there is ANYTHING in a certain array (I mean List) and the repeat with is INSIDE of the first repeat, which repeats it's own loop with everything in the array at that time. Now, one of the actions of the repeat with loop is to change the array. Which I think would change the loop would it not? Example (foldList is A, B, C) repeat until {} repeat with folder_name in foldList do something set foldList to 1, 2, 3 end repeat end repeat What I would THINK that does is iterate through the first loop as "A", but before hitting the end it would change foldList to 1, 2, 3. So instead of going through the next loop as "B" I'd think it would go as "1" instead. But if it did that then I don't think my manual walkthrough would be off by so much. So I'm under the assumption that in Applescript when you're in a repeat with, regardless of changing the List you WILL end that loop on the last item of the first List (before the list was replaced.) Is this right?

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  • Adding an Array inside an array in a PHP function

    - by bateman_ap
    I have created a function in PHP that calls a webservice and parses through the result, assinging values to variables and returning them all as an Array. This all works perfectly, however I have come across a need to have an "array within my array" I am assigning values as below: $productName = $product->Name; $productID = $product->ID; $productArray = array( 'productName' => "$productName", 'productID' => "$productID" ); return $productArray; However I now have a piece of data that comes back with multiple results so I need to have a additional array to store these, I am getting the values from the returned XML using a foreach loop, however I want to be able to add them to the array with a name so I can reference them in the returned data, this is where I have a problem... $bestForLists = $product->BestFors; foreach( $bestForLists as $bestForList ) { $productBestFors = $bestForList->BestFor; foreach( $productBestFors as $productBestFor ) { $productBestForName = $productBestFor->Name; $productBestForID = $productBestFor->ID; } } I tried creating an array for these using the below code: $bestForArray[] = (array( "productBestForID" => "$productBestForID", "productBestForName" => "$productBestForName" )); And then at the end merging these together: $productArray= array_merge($productArray,$bestForArray); If I print out the returned value I get: Array ( [productName] => Test Product [productID] => 14128 [0] => Array ( [productBestForID] => 56647 [productBestForName] => Lighting ) [1] => Array ( [productBestForID] => 56648 [productBestForName] => Sound ) ) I would like to give the internal Array a name so I can reference it in my code, or is there a better way of doing this, at the moment I am using the following in my PHP page to get values: $productName = $functionReturnedValues['productName']; I would like to use the following to access the array I could then loop through: $bestForArray = $functionReturnedValues['bestForArray']; Hope someone can help

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  • How to output an array's content in columns in BASH.

    - by Arko
    I wanted to display a long list of strings from an array. Right now, my script run through a for loop echoing each value to the standard output: for value in ${values[@]} do echo $value done Yeah, that's pretty ugly! And the one column listing is pretty long too... I was wondering if i can find a command or builtin helping me to display all those values in columns, like the ls command does by default when listing a directory (ls -C). [Update] Losing my brain with column not displaying properly formatted columns, here's more info: The values: $ values=( 01----7 02----7 03-----8 04----7 05-----8 06-----8 07-----8 08-----8 09---6 10----7 11----7 12----7 13----7 14-----8 15-----8 16----7 17----7 18---6 19-----8 20-----8 21-----8) (Notice the first two digits as an index and the last one indicating the string length for readability) The command: echo " ${values[@]/%/$'\n'}" | column The result: Something is going wrong...

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  • How to define and work with an array of bits in C?

    - by Eddy
    I want to create a very large array on which I write '0's and '1's. I'm trying to simulate a physical process called random sequential adsorption, where units of length 2, dimers, are deposited onto an n-dimensional lattice at a random location, without overlapping each other. The process stops when there is no more room left on the lattice for depositing more dimers (lattice is jammed). Initially I start with a lattice of zeroes, and the dimers are represented by a pair of '1's. As each dimer is deposited, the site on the left of the dimer is blocked, due to the fact that the dimers cannot overlap. So I simulate this process by depositing a triple of '1's on the lattice. I need to repeat the entire simulation a large number of times and then work out the average coverage %. I've already done this using an array of chars for 1D and 2D lattices. At the moment I'm trying to make the code as efficient as possible, before working on the 3D problem and more complicated generalisations. This is basically what the code looks like in 1D, simplified: int main() { /* Define lattice */ array = (char*)malloc(N * sizeof(char)); total_c = 0; /* Carry out RSA multiple times */ for (i = 0; i < 1000; i++) rand_seq_ads(); /* Calculate average coverage efficiency at jamming */ printf("coverage efficiency = %lf", total_c/1000); return 0; } void rand_seq_ads() { /* Initialise array, initial conditions */ memset(a, 0, N * sizeof(char)); available_sites = N; count = 0; /* While the lattice still has enough room... */ while(available_sites != 0) { /* Generate random site location */ x = rand(); /* Deposit dimer (if site is available) */ if(array[x] == 0) { array[x] = 1; array[x+1] = 1; count += 1; available_sites += -2; } /* Mark site left of dimer as unavailable (if its empty) */ if(array[x-1] == 0) { array[x-1] = 1; available_sites += -1; } } /* Calculate coverage %, and add to total */ c = count/N total_c += c; } For the actual project I'm doing, it involves not just dimers but trimers, quadrimers, and all sorts of shapes and sizes (for 2D and 3D). I was hoping that I would be able to work with individual bits instead of bytes, but I've been reading around and as far as I can tell you can only change 1 byte at a time, so either I need to do some complicated indexing or there is a simpler way to do it? Thanks for your answers

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  • Initialize Static Array of Structs in C

    - by russell_h
    I implementing a card game in C. There are lots of types of cards and each has a bunch of information, including some actions that will need to be individually scripted associated with it. Given a struct like this (and I'm not certain I have the syntax right for the function pointer) struct CARD { int value; int cost; // This is a pointer to a function that carries out actions unique // to this card int (*do_actions) (struct GAME_STATE *state, int choice1, int choice2); }; I would like to initialize a static array of these, one for each card. I'm guessing this would look something like this int do_card0(struct GAME_STATE *state, int choice1, int choice2) { // Operate on state here } int do_card1(struct GAME_STATE *state, int choice1, int choice2) { // Operate on state here } extern static struct cardDefinitions[] = { {0, 1, do_card0}, {1, 3, do_card1} }; Will this work, and am I going about this the right way at all? I'm trying to avoid huge numbers of switch statements. Do I need to define the 'do_cardN' functions ahead of time, or is there some way to define them inline in the initialization of the struct (something like a lambda function in python)? I'll need read-only access to cardDefinitions from a different file - is 'extern static' correct for that? I know this is a lot of questions rolled into one but I'm really a bit vague about how to go about this. Thanks.

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  • Resizing a rectangular array

    - by devdept
    Does a smarter way than the following exist to resize a rectangular array? double[,] temp = new double[newSize, originalSecondDimension]; Array.Copy(original, temp, original.Length); I was concerned about duplicating a huge array and the memory necessary to do it. What does the Array.Resize() do internally? Thanks, Alberto

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  • Adding rows to an array in PHP

    - by ChuckO
    I have loaded an associative array of records from a MySQL database table. The array consists of 1 to 7 rows representing one week of entries, which might not have been entered for each day. How can I insert blank rows into the array for the missing days so that I can easily display the data in a table? I don't need to update the database with the blanks.

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  • List of Big-O for PHP functions?

    - by Kendall Hopkins
    After using PHP for a while now, I've noticed that not all PHP built in functions as fast as expected. Consider the below two possible implementations of a function that finds if a number is prime using a cached array of primes. //very slow for large $prime_array $prime_array = array( 2, 3, 5, 7, 11, 13, .... 104729, ... ); $result_array = array(); foreach( $array_of_number => $number ) { $result_array[$number] = in_array( $number, $large_prime_array ); } //still decent performance for large $prime_array $prime_array => array( 2 => NULL, 3 => NULL, 5 => NULL, 7 => NULL, 11 => NULL, 13 => NULL, .... 104729 => NULL, ... ); foreach( $array_of_number => $number ) { $result_array[$number] = array_key_exists( $number, $large_prime_array ); } This is because in_array is implemented with a linear search O(n) which will linearly slow down as $prime_array grows. Where the array_key_exists function is implemented with a hash lookup O(1) which will not slow down unless the hash table gets extremely populated (in which case it's only O(logn)). So far I've had to discover the big-O's via trial and error, and occasionally looking at the source code. Now for the question... I was wondering if there was a list of the theoretical (or practical) big O times for all* the PHP built in functions. *or at least the interesting ones For example find it very hard to predict what the big O of functions listed because the possible implementation depends on unknown core data structures of PHP: array_merge, array_merge_recursive, array_reverse, array_intersect, array_combine, str_replace (with array inputs), etc.

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  • Problem with array of elements of a structure type

    - by kobac
    I'm writing an app in Visual Studio C++ and I have problem with assigning values to the elements of the array, which is array of elements of structure type. Compiler is reporting syntax error for the assigning part of the code. Is it possible in anyway to assign elements of array which are of structure type? typedef struct { CString x; double y; } Point; Point p[3]; p[0] = {"first", 10.0}; p[1] = {"second", 20.0}; p[2] = {"third", 30.0};

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  • Clean up State field with T-SQL?

    - by Pselus
    The State field in our database is a mess. There was no validation when it was filled so we have everything from two letter abbreviations to full state names to misspelled state names to "test" and "xxxx", etc. I am not going to try to handle everything, but for sure I want to fix the correct state names to abbreviations. I have a list of valid state names and abbreviations, but I don't know how I can do this: UPDATE Table SET State = ('AR','AK') WHERE (SELECT * FROM Table WHERE State IN ('Arkansas','Alaska')) Basically, can I update a field to be something from a list by the location it is in another list?

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  • Int[] Reverse - What does this actually do?

    - by Jamie Dixon
    I was just having a play around with some code in LINQPad and noticed that on an int array there is a Reverse method. Usually when I want to reverse an int array I'd do so with Array.Reverse(myIntArray); Which, given the array {1,2,3,4} would then return 4 as the value of myIntArray[0]. When I used the Reverse() method directly on my int array: myIntArray.Reverse(); I notice that myIntArray[0] still comes out as 1. What is the Reverse method actually doing here?

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  • generic function for extracting values from an array with one particular key in PHP

    - by Sabya
    Is it possible in PHP to extract values from an array with a particular key path and return an array of those values? I'll explain with an example: $user = array ( array( id => 1, email =>'[email protected]', project => array ('project_id' => 222, 'project_name' => 'design') ), array( id => 2, email =>'[email protected]', project => array ('project_id' => 333, 'project_name' => 'design') ) ); /** I have to write a function something like: */ $projectIds = extractValuesWithKey($user, array('project', 'project_id')); print_r($projectIds); Output: Array( [0] => 222, [1] => 333 )

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  • Fastest way to represent a collection of bits in PHP?

    - by Piskvor
    What is a good way to represent a collection of bits? I have a set of various on/off toggles (thousands of them) and need to store and retrieve their state. The naïve implementation would be an array of booleans, but I'm wondering if there's a better way (better in terms of access speed and/or memory requirements). I've found this BitArray implementation, but it's limited to 32 bits, which is not enough for this case.

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  • Truncating a string while storing it in an array in c

    - by Nick
    I am trying to create an array of 20 character strings with a maximum of 17 characters that are obtained from a file named "words.dat". After that the program should truncate the string only showing the first 17 characters and completely ignore the rest of that string. However My question is: I am not quite sure how to accomplish this, can anyone give me some insight on how to accomplish this task? Here is my current code as is: #include <stdio.h> #include <stdlib.h> #define WORDS 20 #define LENGTH 18 char function1(char[WORDS][LENGTH]); int main( void ) { char word_array [WORDS] [LENGTH]; function1(word_array); return ( 0 ) ; } char function1(char word_array[WORDS][LENGTH]) { FILE *wordsfile = fopen("words.dat", "r"); int i = 0; if (wordsfile == NULL) printf("\nwords.dat was not properly opened.\n"); else { for (i = 0; i < WORDS; i++) { fscanf(wordsfile, "%17s", word_array[i]); printf ("%s \n", word_array[i]); } fclose(wordsfile); } return (word_array[WORDS][LENGTH]); } words.dat file: Ninja DragonsFury failninja dragonsrage leagueoflegendssurfgthyjnu white black red green yellow green leagueoflegendssughjkuj dragonsfury Sword sodas tiger snakes Swords Snakes sage Sample output: blahblah@fang:~>a.out Ninja DragonsFury failninja dragonsrage leagueoflegendssu rfgthyjnu white black red green yellow green leagueoflegendssu ghjkuj dragonsfury Sword sodas tiger snakes Swords blahblah@fang:~> What will be accomplished afterwards with this program is: After function1 works properly I will then create a second function name "function2" that will look throughout the array for matching pairs of words that match "EXACTLY" including case . After I will create a third function that displays the 20 character strings from the words.dat file that I previously created and the matching words.

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  • mysql_fetch_array() not displaying all results

    - by user1666995
    I have a database with a calendar table (each row represents one day) with 4 years of rows (2012, 2013, 2014, 2015). I use the column name calyear for the year. I use the following code to find values for distinct years then display it: $year = mysql_query("SELECT DISTINCT calyear FROM calendar"); while($yeararray = mysql_fetch_array($year)) { echo($yeararray['calyear']."<br />"); } The problem is it only displays the years 2013, 2014, 2015 even though when I use echo(mysql_num_rows($year); it displays the value 4 which I take to mean all 4 years are there. I'm not quite sure where I'm going wrong with this.

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  • Javascript Canvas Element - Array Of Images

    - by Ben Shelock
    I'm just learning JS, trying to do things without jQuery, and I want to make something similar to this however I want to use an array of images instead of just the one. My image array is formed like this var image_array = new Array() image_array[0] = "image1.jpg" image_array[1] = "image2.jpg" And the canvas element is written like this. (Pretty much entirely taken from the Mozilla site) function draw() { var ctx = document.getElementById('canvas').getContext('2d'); var img = new Image(); img.src = 'sample.png'; img.onload = function(){ for (i=0;i<5;i++){ for (j=0;j<9;j++){ ctx.drawImage(img,j*126,i*126,126,126); } } } } It uses the image "sample.png" in that code but I want to change it to display an image from the array. Displaying a different one each time it loops. Apoligies if I've not explained this well.

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  • Array of strings and char ** environ variable.

    - by Naruto Uzumaki
    Hello! I want to know how an array of strings is declared? What I do is I declare an array of pointers of pointers to strings. Eg. char *array[]= {"string1","string2","string3"}; I was reading about modifying environment variables in Linux and stumbled upon the pointer char **environ ( http://www.cs.bham.ac.uk/resources/courses/2005/17423/doc/libc/Environment-Access.html#Environment-Access ). char **environ is declared as an array of strings. I think it should be a pointer to a pointer. For eg. char *array[]= {"string1","string2","string3"}; environ = array; Am I doing something wrong? I also read somewhere that char *argv[] = char **argv. How is it possible?

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  • How to create list of numbers and append its reverse to it efficiently in Ruby

    - by Kiwi
    Given a minimum integer and maximum integer, I want to create an array which counts from the minimum to the maximum by two, then back down (again by two, repeating the maximum number). For example, if the minimum number is 1 and the maximum is 9, I want [1, 3, 5, 7, 9, 9, 7, 5, 3, 1]. I'm trying to be as concise as possible, which is why I'm using one-liners. In Python, I would do this: range(1, 10, 2) + range(9, 0, -2) In Ruby, which I'm just beginning to learn, all I've come up with so far is: (1..9).inject([]) { |r, num| num%2 == 1 ? r << num : r }.reverse.inject([]) { |r, num| r.unshift(num).push(num) } Which works, but I know there must be a better way. What is it?

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  • generate an array from an array with conditions

    - by Aman
    Suppose i have an array $x = (31,12,13,25,18,10); I want to reduce this array in such a way that the value of each array element is 32. so after work my array will become $newx = (32,32,32,13); I have to generate this array in such a way the sum of array values is never greater than 32. so to create first value, i will reduce 1 from second index value i.e. 12, so the second value will become 11 and first index value will become 31+1 =32. This process should continue so that each array value becomes equal to 32.

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  • Why does my array initialization code cause a StackOverflowException to be thrown?

    - by MCS
    The following line of code in my class constructor is throwing a StackOverflowException: myList = new string[]{}; // myList is a property of type string[] Why is that happening? And what's the proper way to initialize an empty array? UPDATE: The cause was in the set method, in which I was attempting to trim all values. What's wrong with this code: set { for (int i = 0; i < myList.Length; i++) { if (myList[i] != null) myList[i] = myList[i].Trim(); } }

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