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• Elegant way to aggregate multi-demensional array by index key

  - by Stephen J. Fuhry

  How can I recursively find the total value of all children of an array that looks something like this? [0] => Array ( [value] => ? // 8590.25 + 200.5 + 22.4 [children] => Array ( [0] => Array ( [value] => ? // 8590.25 + 200.5 [children] => Array ( [0] => Array ( [value] => 8590.25 // leaf node ) [1] => Array ( [value] => 200.05 // leaf node ) ) ) [1] => Array ( [value] => 22.4 // leaf node ) ) )

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• Generating 2-dimensional vla ends in segmentation fault

  - by Framester

  Hi, further developing the code from yesterday (seg fault caused by malloc and sscanf in a function), I tried with the help of some tutorials I found on the net to generate a 2-dim vla. But I get a segmentation fault at (*data)[i][j]=atof(p);. The program is supposed to read a matrix out of a text file and load it into a 2d array (cols 1-9) and a 1D array (col 10) [Example code] #include<stdio.h> #include<stdlib.h> #include<math.h> #include<string.h> const int LENGTH = 1024; void read_data(float ***data, int **classes, int *nrow,int *ncol, char *filename){ FILE *pfile = NULL; char line[LENGTH]; if(!( pfile=fopen(filename,"r"))){ printf("Error opening %s.", filename); exit(1); } int numlines=0; int numcols=0; char *p; fgets(line,LENGTH,pfile); p = strtok (line," "); while (p != NULL){ p = strtok (NULL, ", "); numcols++; } while(fgets(line,LENGTH,pfile)){ numlines++; } rewind(pfile); int numfeats=numcols-1; *data=(float**) malloc(numlines*sizeof(float*)); *classes=(int *)malloc(numlines*sizeof(int)); if(*classes == NULL){ printf("\nOut of memory."); exit(1); } int i=0; while(fgets(line,LENGTH,pfile)){ p = strtok (line," "); for(int j=0;j<numfeats;j++) { (data)[i]=malloc(numfeats*sizeof(float)); printf("%i ",i); (*data)[i][j]=atof(p); p = strtok (NULL, ", "); } (*classes)[i]=atoi(p); i++; } fclose(pfile); *nrow=numlines; *ncol=numfeats; } int main() { char *filename="somedatafile.txt"; float **data2; int *classes2; int r,c; read_data(&data2,&classes2, &r, &c,filename) ; for(int i=0;i<r;i++){ printf("\n"); for(int j=0;j<c;j++){ printf("%f",data2[i][j]); } } return 1; } [Content of somedatafile.txt] 50 21 77 0 28 0 27 48 22 2 55 0 92 0 0 26 36 92 56 4 53 0 82 0 52 -5 29 30 2 1 37 0 76 0 28 18 40 48 8 1 37 0 79 0 34 -26 43 46 2 1 85 0 88 -4 6 1 3 83 80 5 56 0 81 0 -4 11 25 86 62 4 55 -1 95 -3 54 -4 40 41 2 1 53 8 77 0 28 0 23 48 24 4 37 0 101 -7 28 0 64 73 8 1 ...

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• How do I create and populate a non-uniformly structured array in PHP?

  - by stormist

  I am trying to decide on a data structure for an array that has a date for the key and the amount of bandwidth consumed as values. examples Key Consumed Policy October 50 Basic November 75 Basic December 100 Basic Some months, but not all, will have more than one policy. In that case, I need break them down by policy once the total is shown. So for the above example, assume December had 3 policies. The table i construct from my array would then need to show: Key Consumed Policy October 50 Basic November 75 Basic December 100 .. December 25 Basic December 25 Extended December 50 Premium Could all this data be represented in an array ? $myArray['december'] would be a different data structure than the others because it would need a last entry, probably another array, that had the policy names as keys and the amount of data consumed as values. Does PHP allow for arrays that are not structured uniformly? i.e. key october and November have only 2 entries under their key while December has 2 entries plus a 3rd which is an additional array. My best guess is something like: Array ( [October] => "50", "Basic" [November] => "75", "Basic" [December] => "100", "..", Array( [Basic] => 25 [Extended] =>25 [Premium] => 50 ) ) My question is if this is possible and how to declare it and populate it with values with PHP. Thanks in advance for any clarifications or assistance!

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• Write a foreach loop for this array.

  - by mjames

  Hi, I am using the xpath in php5 to parse a xml document. The problem I have is writing a foreach to correctly display the following array array(1) { [0]= object(SimpleXMLElement)#21 (2) { ["file"]= string(12) "value 1" ["folder"]= string(8) "value 2" } } Ideally i would like to get the value by using $row['file'] or $row['folder']. Thanks for any help.

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• Zend framework : how to extract a column from mysql result set?

  - by understack

  What would be the best way to extract a column out of mysql results set? My result set is like: [0] = ('id'=>1, 'name'=>a), [1] = ('id'=>2, 'name'=>b), [2] = ('id'=>3, 'name'=>c) How can I extract 'name' column as an array from this? I can do it using for loop. But wondering if there are any better reusable solution?

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• Array of an array (Database)

  - by Anne Mah Li'en

  I am trying to print out an array of an array from database Below are my codes. I am able to retrieve all the values from the first array. But error occurs when I am trying to retrieve the 2nd array from database. <% ArrayList<Questionnaire> allCategories =QuestionnaireController.getQuestionnaireByCategoryAll(); for(int i=0;i<allCategories.size();i++){ Questionnaire allCategoriesQuestionnaire=allCategories.get(i); out.println("<div class=\"silverheader\">" + "<a href= \"\">" + allCategoriesQuestionnaire.getCategory() + "</a>" + "</div>" + "<div class=\"submenu\">" + "ArrayList<Questionnaire> CategoriesSustainability =QuestionnaireController.getQuestionnaireByCategorySustainability();" + out.println(CategoriesSustainability.get(0).getCategory()); + "<br />" + "</div>"); } %>

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• Get the top nth values from a rectangular array

  - by user355925

  I am reading a txt file for strings that represent integers. The file is space delimited. I have created an array[10,2]. Everytime the strings 1~10 is found in the file I increment array[n,0] by 1. I also feed array[n,1] with numbers 1~10. i.e. txt file contents: 1/1/1 10/1/2001 1 1 10 2 2 3 1 5 10 word word 3 3 etc.. streamreader reads 1/1/1 and determines that is is not 1~10 streamreader reads 10/1/2001 and determines that it is not 1~10 streamreader reads 1 and ++array[0,0] streamreader reads 1 and ++array[0,0] streamreader reads 10 and ++array[9,0] etc.. The result will be: '1' was found 3 times '2' was found 2 times '3' was found 3 times '5' was found 1 time '10' was found 2 times My problem is that I need this array placed in order(sorted) by value of column 0 so that it would be: 1 3 2 10 5

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• Populate array from vector

  - by Zag zag..

  Hi, I would like to populate an 2 dimensional array, from a vector. I think the best way to explain myself is to put some examples (with a array of [3,5] length). When vector is: [1, 0] [ [4, 3, 2, 1, 0], [4, 3, 2, 1, 0], [4, 3, 2, 1, 0] ] When vector is: [-1, 0] [ [0, 1, 2, 3, 4], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4] ] When vector is: [-2, 0] [ [0, 0, 1, 1, 2], [0, 0, 1, 1, 2], [0, 0, 1, 1, 2] ] When vector is: [1, 1] [ [2, 2, 2, 1, 0], [1, 1, 1, 1, 0], [0, 0, 0, 0, 0] ] When vector is: [0, 1] [ [2, 2, 2, 2, 2], [1, 1, 1, 1, 1], [0, 0, 0, 0, 0] ] Have you got any ideas, a good library or a plan? Any comments are welcome. Thanks. Note: I consulted Ruby "Matrix" and "Vector" classes, but I don't see any way to use it in my way... Edit: In fact, each value is the number of cells (from the current cell to the last cell) according to the given vector. If we take the example where the vector is [-2, 0], with the value *1* (at array[2, 3]): array = [ [<0>, <0>, <1>, <1>, <2>], [<0>, <0>, <1>, <1>, <2>], [<0>, <0>, <1>, *1*, <2>] ] ... we could think such as: The vector [-2, 0] means that -2 is for cols and 0 is for rows. So if we are in array[2, 3], we can move 1 time on the left (left because 2 is negative) with 2 length (because -2.abs == 2). And we don't move on the top or bottom, because of 0 for rows.

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• ruby sortby 3rd element in a multidimential array npot working properly

  - by Steven

  Hi, I'm using ruby to sort an array where each element in the array is another array. I have this: Data = Data.SortBy { |Info| info[3] } example data in this column: 3.1 2 5.65 -1 0.4 -9.43 -10.87 -2.3 It should sort this into: 5.65 3.1 2 0.4 -1 -2.3 -9.43 -10.87 But it comes out like this: 5.65 3.1 2 0.4 -1 -10.87 -2.3 -9.43 It's only comparing the first char of the float... not the whole number?

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• Android java assigning 2d array to 3d array

  - by semajhan

  I'm running into problems trying to assign a 2d array to a 3d array, so I thought i'd ask a question about 3d and 2d arrays. Say I have a masterArray[][][] and wanted to put childArray1[][] and childArray2[][] into it. This is how I have done it and was wondering if that is the correct way of applying it: private int[][][] masterArray; private int[][] childArray1 = { {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 1, 1, 0, 0, 1, 0, 1, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 0, 1, 1, 1, 1, 1, 1, 0, 1}, {1, 0, 1, 1, 1, 1, 0, 1, 0, 1}, {1, 0, 1, 1, 0, 1, 0, 1, 0, 1}, {1, 0, 1, 1, 0, 1, 1, 1, 0, 1}, {1, 0, 1, 1, 1, 1, 1, 1, 0, 1}, {1, 0, 1, 1, 0, 1, 1, 1, 0, 1}, {1, 0, 1, 1, 0, 1, 8, 1, 0, 1}, {1, 0, 7, 1, 1, 1, 0, 1, 0, 1}, {1, 0, 1, 1, 1, 1, 0, 1, 0, 1}, {1, 0, 1, 1, 1, 1, 1, 1, 0, 1}, {1, 0, 0, 0, 0, 0, 0, 9, 0, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1} }; private int[][] childArray2 = { {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {0, 0, 0, 0, 0, 0, 0, 0, 1, 1}, {1, 1, 1, 1, 7, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 0, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 0, 0, 0, 1, 1, 1}, {1, 1, 1, 9, 1, 1, 8, 0, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, {1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, }; Ok, so in my init method I use these some methods to set the child arrays into the master array. What I was curious about was how this exactly works. I assumed the following: masterLevel = new int[MAX_LEVELS][MAP_WIDTH][MAP_HEIGHT]; for (int x = 0; x < MAP_WIDTH; x++) { for (int y = 0; y < MAP_HEIGHT; y++) { masterArray[currentLevel][x][y] = childArray1[x][y]; } } Would that work? In my application things aren't working so I picking out code that I am not 100% sure on.

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• Need an efficient algorithm solve this kind of complex structure

  - by Rizvan

  Problem Statement is : Given 2 Dimensional array, print output for example If 4 rows and 6 columns, output would be: 1 2 3 4 5 6 16 17 18 19 20 7 15 24 23 22 21 8 14 13 12 11 10 9 I tried it is looking like square within square but when I attempted this problem, I put so many while and if loops but didn't got exact answer. If row and columns increases how to handle it? This is not homework. I was learning solving complex structure so I need to understand it by some guidance.

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• jquery to create array from form data

  - by AndrewStevens

  I've been wrestling with this problem for a couple hours now. Essentially, what I need to do is take the following or similar HTML: <div id="excpdivs"> <div class="excpdiv" id="excpdiv0"> Date: <input name="excp[0][date]"> Open: <input name="excp[0][open]"> Close: <input name="excp[0][close]"> </div> <div class="excpdiv" id="expdiv1"> Date: <input name="excp[1][date]"> Open: <input name="excp[1][open]"> Close: <input name="excp[1][close]"> </div> and get an array similar to the following to a php script: Array ( [0] => Array ( [date] => 2012-09-15 [open] => 3:00 [close] => 5:00 ) [1] => Array ( [date] => 2012-09-16 [open] => 2:00 [close] => 5:00 ) ) My main problem is getting the values from the input elements. My latest attempt is the following: var results = []; $(".excpdiv").each(function(){ var item = {}; var inpts = $(this).find("input"); item.date = $(inpts.get(0)).val(); item.open = $(inpts.get(1)).val(); item.close = $(inpts.get(2)).val(); results.push(item); }); Am I on the right track or am I hopelessly lost?

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• C# print 2D-array in order. Please help!

  - by user339067

  Hello, I got a 2-dimentional array containing boolean values written in C#. The cols and rows of the array are to be determined by the user upon creation of the array. I then want to print out the array and it´s containing values onto the console in order. For example like this, how is this done in C#? ROWS - COLS - VALUE 1 - A - True 1 - B - True 1 - C - True 1 - D - True 2 - A - True 2 - B - False 2 - C - False 2 - D - True

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• Populating a color array with every 8th pixel in an image. C#

  - by Piper

  I have an image that is 512x280 pixels. I want to populate a 64x35 array with every 8th pixel in the matrix. Here is what I have right now: Color[,] imgArray = new Color[b.Width, b.Height]; for (int y = 0; y < 35; y++) { for (int x = 0; x < 64; x++) { imgArray[x, y] = b.GetPixel(x, y); } } But that will get just the top corner of the image. How would I change the loop so it grabs every 8th pixel to fill the array with? edit: I think I may have gotten it. Can someone read this and assure me that it is correct? Color[,] imgArray = new Color[64, 35]; for (int y = 0; y < 280; y+=8) { for (int x = 0; x < 512; x+=8) { imgArray[x, y] = b.GetPixel(x, y); } }

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• PHP multi-post issue.

  - by user1887185

  When I have two or more comments on a post, it show the post again and the next comment underneath it. How do I make it so it shows only the post once and the comments underneath it if there are multiple comments? $sql_posts = mysql_query("SELECT * FROM posts ORDER BY post_date DESC "); $postDisplayList = ""; while($row = mysql_fetch_array($sql_posts)){ $postid = $row["id"]; $uid = $row["user_id"]; $the_post = $row["post"]; $post_date = $row["post_date"]; $sql_mem_data = mysql_query("SELECT id, username, firstname, lastname FROM users WHERE id='$uid' LIMIT 1"); while($row = mysql_fetch_array($sql_mem_data)){ $uid = $row["id"]; $username = $row["username"]; $firstname = $row["firstname"]; $lastname = $row["lastname"]; } $sql_com_data = mysql_query("SELECT * FROM comments WHERE post_id='$postid' "); while($row = mysql_fetch_assoc($sql_com_data)){ $uid1 = $row["user_id"]; $comment = $row["comment"]; $whencomment = $row["comment_date"]; $sql_com_data_user = mysql_query("SELECT * FROM users WHERE id='$uid1' "); while($row = mysql_fetch_array($sql_com_data_user)){ $username1 = $row["username"]; $firstname1 = $row["firstname"]; $lastname1 = $row["lastname"]; } $postDisplayList .= ' <table width="100%" align="center" cellpadding="6" style="background-color:#F2F2F2; "> <tr> <td width="93%" bgcolor="#F2F2F2" style="line-height:1.5em;" valign="top"> <span class="liteGreyColor textsize9"> ' . $post_date . ' <a href="profile.php?id=' . $uid . '"><strong>' . $username . '</strong></a></span><br /> <span class="textsize14"> ' . $the_post . '</span> </td> </tr> <tr> <td width="93%" bgcolor="#F2F2F2" style="line-height:1.5em;" valign="top"> <span class="liteGreyColor textsize9"> ' . $whencomment . ' <a href="profile.php?id=' . $uid1 . '"><strong>' . $username1 . '</strong></a></span><br /> <span class="textsize14"> ' . $comment . '</span> </td> </tr> </table>';

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• Convert complex numerical array to associative array [PHP]

  - by user1500412

  I have an array data that look like this : Array ( [0] => Array ( [0] => Name: [1] => John W. [2] => Registration ID: [3] => 36 ) [1] => Array ( [0] =>Age: [1] => 35 [2] => Height: [3] => 5'11" ) [3] => Array ( [0] => Sex: [1] => M [2] => Weight: [3] => 200lbs ) [4] => Array ( [0] => Address ) [5] => Array ( [0] => 6824 crestwood dr delphi, IN 46923 )) And I want to convert it to associative array like this : Array( ['Name']=> John W. ['Registration ID']=> 36 ['Age']=> 35 ['Height'] => 5'11'' ['Sex']=>M ['Weight']=>200lbs ['Address']=>6824 crestwood dr delphi, IN 46923 ) I have no idea at all how to do this, since the supposed to be array column header were also in sequence, so it makes difficult to convert this array. Any help I appreciate, thx.

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• How to send an array(multidimensional/associative) and some varaibles together through json?

  - by I Like PHP

  i have an multidimensional array $ouptput=Array ( [0] => Array ( [0] => mov_1 [1] => MY FAIR LADY ) [1] => Array ( [1] => mov_10 [2] => love actually ) ) and two variables $avlblQnty=50 $success= true when i send these data via json echo json_encode( array('movieData'=>$output,'stock'=>$avlblQnty,'sucess'=>$success)); it returns {"movieData":[["mov_1","MY FAIR LAD],{"1":"mov_10","2":"love actually"}],"stock":0,"success":true} but i need json encoded data properly so that i can create an select box on movieData using(movieData.length), so for that i want json edcoded data in below format so that i can retrive successfully {"movieData":[{"mov_1":"MY FAIR LAD,mov_10":"love actually"}],"stock":0,"success":true} i want to know how to send an array(multidimensional/associative) and some varaibles together through json?

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• : for displaying all elements in a multidimensional array in python 3.1.

  - by Leif Andersen

  I have a multidimensional array in python like: arr = [['foo', 1], ['bar',2]] Now, if I want to print out everything in the array, I could do: print(arr[:][:]) Or I could also just do print(arr). However, If I only wanted to print out the first element of each box (for arr, that would be 'foo', 'bar'), I would imagine I would do something like: print(arr[:][0]) however, that just prints out the first data blog (['foo', 1]), also, I tried reversing it (just in case): print(arr[0][:]) and I got the same thing. So, is there anyway that I can get it to print the first element in each tuple (other than: for tuple in arr: print(tuple[0]) )? Thanks.

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• PHP arrays - How to 1-dimensional array into nested multidimensional array?

  - by sombe

  When retrieving a hierarchical structure from MySQL (table with one ID column and one PARENT column signifying the hierarchical relationships), I map the result into an enumerated array as follows (for this example the numbers are arbitrary): Array ( [3] => Array ( [7] => Array () ), [7] => Array ( [8] => Array () ) ) Notice 3 is the parent of 7, and 7 is the parent of 8 (this could go on and on; and any parent could have multiple children). I wanted to shrink this array into a nested multidimensional array as follows: Array ( [3] => Array ( [7] => Array ( [8] => Array () ) ) ) That is, each NEW id is automatically assigned an empty array. Regardless, any ID's children will be pushed into their parent's array. Take a look at the following illustration for further clarification: This will probably result in a complicated recursive operation, since I always have to check whether a parent with any certain ID already exists (and if so, push the value into its array). Is there a built-in php function that can assist me with this? Do you have any idea as to how to go about constructing this? For what it's worth I'm using this to built a navigation bar in wordpress (which can contain categories, subcategories, posts... essentially anything).

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• If Key Value pair exists in multidimensional array.. How to?

  - by Daniel White

  I have a codeigniter shopping cart going and its "cart" array is the following: Array ( [a87ff679a2f3e71d9181a67b7542122c] => Array ( [rowid] => a87ff679a2f3e71d9181a67b7542122c [id] => 4 [qty] => 1 [price] => 12.95 [name] => Maroon Choir Stole [image] => 2353463627maroon_3.jpg [custprod] => 0 [subtotal] => 12.95 ) [8f14e45fceea167a5a36dedd4bea2543] => Array ( [rowid] => 8f14e45fceea167a5a36dedd4bea2543 [id] => 7 [qty] => 1 [price] => 12.95 [name] => Shiny Red Choir Stole [image] => 2899638984red_vstole_1.jpg [custprod] => 0 [subtotal] => 12.95 ) [eccbc87e4b5ce2fe28308fd9f2a7baf3] => Array ( [rowid] => eccbc87e4b5ce2fe28308fd9f2a7baf3 [id] => 3 [qty] => 1 [price] => 14.95 [name] => Royal Blue Choir Stole [image] => 1270984005royal_vstole.jpg [custprod] => 1 [subtotal] => 14.95 ) ) My goal is to loop through this multidimensional array some how and if ANY product with the key value pair "custprod == 1" exists, then my checkout page will display one thing, and if no custom products are in the cart it displays another thing. Any help is appreciated. Thanks.

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• c#: Clean way to fit a collection into a multidimensional array?

  - by Rosarch

  I have an ICollection<MapNode>. Each MapNode has a Position attribute, which is a Point. I want to sort these points first by Y value, then by X value, and put them in a multidimensional array (MapNode[,]). The collection would look something like this: (30, 20) (20, 20) (20, 30) (30, 10) (30, 30) (20, 10) And the final product: (20, 10) (20, 20) (20, 30) (30, 10) (30, 20) (30, 30) Here is the code I have come up with to do it. Is this hideously unreadable? I feel like it's more hacky than it needs to be. private Map createWorldPathNodes() { ICollection<MapNode> points = new HashSet<MapNode>(); Rectangle worldBounds = WorldQueryUtils.WorldBounds(); for (float x = worldBounds.Left; x < worldBounds.Right; x += PATH_NODE_CHUNK_SIZE) { for (float y = worldBounds.Y; y > worldBounds.Height; y -= PATH_NODE_CHUNK_SIZE) { // default is that everywhere is navigable; // a different function is responsible for determining the real value points.Add(new MapNode(true, new Point((int)x, (int)y))); } } int distinctXValues = points.Select(node => node.Position.X).Distinct().Count(); int distinctYValues = points.Select(node => node.Position.Y).Distinct().Count(); IList<MapNode[]> mapNodeRowsToAdd = new List<MapNode[]>(); while (points.Count > 0) // every iteration will take a row out of points { // get all the nodes with the greatest Y value currently in the collection int currentMaxY = points.Select(node => node.Position.Y).Max(); ICollection<MapNode> ythRow = points.Where(node => node.Position.Y == currentMaxY).ToList(); // remove these nodes from the pool we're picking from points = points.Where(node => ! ythRow.Contains(node)).ToList(); // ToList() is just so it is still a collection // put the nodes with max y value in the array, sorting by X value mapNodeRowsToAdd.Add(ythRow.OrderByDescending(node => node.Position.X).ToArray()); } MapNode[,] mapNodes = new MapNode[distinctXValues, distinctYValues]; int xValuesAdded = 0; int yValuesAdded = 0; foreach (MapNode[] mapNodeRow in mapNodeRowsToAdd) { xValuesAdded = 0; foreach (MapNode node in mapNodeRow) { // [y, x] may seem backwards, but mapNodes[y] == the yth row mapNodes[yValuesAdded, xValuesAdded] = node; xValuesAdded++; } yValuesAdded++; } return pathNodes; } The above function seems to work pretty well, but it hasn't been subjected to bulletproof testing yet.

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• Where can I find information on the Get, Set and Address methods for multidimensional System.Array i

  - by Rob Smallshire

  System.Array serves as the base class for all arrays in the Common Language Runtime (CLR). According to this article, For each concrete array type, [the] runtime adds three special methods: Get/Set/Address. and indeed if I disassemble this C# code, int[,] x = new int[1024,1024]; x[0,0] = 1; x[1,1] = 2; x[2,2] = 3; Console.WriteLine(x[0,0]); Console.WriteLine(x[1,1]); Console.WriteLine(x[2,2]); into CIL I get, IL_0000: ldc.i4 0x400 IL_0005: ldc.i4 0x400 IL_000a: newobj instance void int32[0...,0...]::.ctor(int32, int32) IL_000f: stloc.0 IL_0010: ldloc.0 IL_0011: ldc.i4.0 IL_0012: ldc.i4.0 IL_0013: ldc.i4.1 IL_0014: call instance void int32[0...,0...]::Set(int32, int32, int32) IL_0019: ldloc.0 IL_001a: ldc.i4.1 IL_001b: ldc.i4.1 IL_001c: ldc.i4.2 IL_001d: call instance void int32[0...,0...]::Set(int32, int32, int32) IL_0022: ldloc.0 IL_0023: ldc.i4.2 IL_0024: ldc.i4.2 IL_0025: ldc.i4.3 IL_0026: call instance void int32[0...,0...]::Set(int32, int32, int32) IL_002b: ldloc.0 IL_002c: ldc.i4.0 IL_002d: ldc.i4.0 IL_002e: call instance int32 int32[0...,0...]::Get(int32, int32) IL_0033: call void [mscorlib]System.Console::WriteLine(int32) IL_0038: ldloc.0 IL_0039: ldc.i4.1 IL_003a: ldc.i4.1 IL_003b: call instance int32 int32[0...,0...]::Get(int32, int32) IL_0040: call void [mscorlib]System.Console::WriteLine(int32) IL_0045: ldloc.0 IL_0046: ldc.i4.2 IL_0047: ldc.i4.2 IL_0048: call instance int32 int32[0...,0...]::Get(int32, int32) IL_004d: call void [mscorlib]System.Console::WriteLine(int32) where the calls to the aforementioned Get and Set methods can be clearly seen. It seems the arity of these methods is related to the dimensionality of the array, which is presumably why they are created by the runtime and are not pre-declared. I couldn't locate any information about these methods on MSDN and their simple names makes them resistant to Googling. I'm writing a compiler for a language which supports multidimensional arrays, so I'd like to find some official documentation about these methods, under what conditions I can expect them to exist and what I can expect their signatures to be. In particular, I'd like to know whether its possible to get a MethodInfo object for Get or Set for use with Reflection.Emit without having to create an instance of the array with correct type and dimensionality on which to reflect, as is done in the linked example.

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• Simple C++ program on multidimensional arrays - Getting C2143 error among others. Not sure why?

  - by noobzilla

  Here is my simple multidimensional array program. The first error occurs where I declare the function addmatrices and then a second one where it is implemented. I am also getting an undefined variable error for bsize. What am I doing incorrectly? #include <iostream> #include <fstream> #include <string> #include <iomanip> using namespace std; //Function declarations void constmultiply (double matrixA[][4], int asize, double matrixC[][4], int bsize, double multiplier); //Pre: The address of the output file, the matrix to be multiplied by the constant, the matrix in which // the resultant values will be stored and the multiplier are passed in. //Post: The matrix is multiplied by the multiplier and the results are displayed on screen and written to the // output file. int addmatrices (double matrixA[][4], int asize, double matrixB[]4], int bsize, double matrixC[][4], int csize); //Pre: The addresses of three matrices are passed in //Post: The values in each of the two matrices are added together and put into a third matrix //Error Codes int INPUT_FILE_FAIL = 1; int UNEQUAL_MATRIX_SIZE = 2; //Constants const double multiplier = 2.5; const int rsize = 4; const int csize = 4; //Main Driver int main() { //Declare the two matrices double matrix1 [rsize][csize]; double matrix2 [rsize][csize]; double matrix3 [rsize][csize]; //Variables double temp; string filename; //Declare filestream object ifstream infile; //Ask the user for the name of the input file cout << "Please enter the name of the input file: "; cin >> filename; //Open the filestream object infile.open(filename.c_str()); //Verify that the input file opened correctly if (infile.fail()) { cout << "Input file failed to open" <<endl; exit(INPUT_FILE_FAIL); } //Begin reading in data from the first matrix for (int i = 0; i <= 3; i++)//i = row { for (int j = 0; j <= 3; j++)// j = column { infile >> temp; matrix1[i][j] = temp; } } //Begin reading in data from the second matrix for (int k = 0; k <= 3; k++)// k = row { for (int l = 0; l <= 3; l++)// l = column { infile >> temp; matrix2[k][l] = temp; } } //Notify user cout << "Input file open, reading matrices...Done!" << endl << "Read in 2 matrices..."<< endl; //Output the values read in for Matrix 1 for (int i = 0; i <= 3; i++) { for (int j = 0; j <= 3; j ++) { cout << setprecision(1) << matrix1[i][j] << setw(8); } cout << "\n"; } cout << setw(40)<< setfill('-') << "-" << endl ; //Output the values read in for Matrix 2 for (int i = 0; i <= 3; i++) { for (int j = 0; j <= 3; j ++) { cout << setfill(' ') << setprecision(2) << matrix2[i][j] << setw(8); } cout << "\n"; } cout << setw(40)<< setfill('-') << "-" << endl ; //Multiply matrix 1 by the multiplier value constmultiply (matrix1, rsize, matrix3, rsize, multiplier); //Output matrix 3 values to screen for (int i = 0; i <= 3; i++) { for (int j = 0; j <= 3; j ++) { cout << setfill(' ') << setprecision(2) << matrix3[i][j] << setw(8); } cout << "\n"; } cout << setw(40)<< setfill('-') << "-" << endl ; // //Add matrix1 and matrix2 // addmatrices (matrix1, 4, matrix2, 4, matrix3, 4); // //Finished adding. Now output matrix 3 values to screen // for (int i = 0; i <= 3; i++) // { //for (int j = 0; j <= 3; j ++) //{ // cout << setfill(' ') << setprecision(2) << matrix3[i][j] << setw(8); //} //cout << "\n"; // } // cout << setw(40)<< setfill('-') << "-" << endl ; //Close the input file infile.close(); return 0; } //Function implementation void constmultiply (double matrixA[][4], int asize, double matrixC[][4], int bsize, double multiplier) { //Loop through each row and multiply the value at that location with the multiplier for (int i = 0; i < asize; i++) { for (int j = 0; j < 4; j++) { matrixC[i][j] = matrixA[i][j] * multiplier; } } } int addmatrices (double matrixA[][4], int asize, double matrixB[]4], int bsize, double matrixC[][4], int csize) { //Remember that you can only add two matrices that have the same shape - i.e. They need to have an equal //number of rows and columns. Let's add some error checking for that: if(asize != bsize) { cout << "You are attempting to add two matrices that are not equal in shape. Program terminating!" << endl; return exit(UNEQUAL_MATRIX_SIZE); } //Confirmed that the matrices are of equal size, so begin adding elements for (int i = 0; i < asize; i++) { for (int j = 0; j < bsize; j++) { matrixC[i][j] = matrixA[i][j] + matrixB[i][j]; } } }

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• How do I sort a multidimensional hash array by a key maybe three levels in, in PHP?

  - by Chris Denman

  I am moving from Perl to PHP and am struggling to get my head around PHP sorting. Here's what I have in Perl: $log{12345}{0}{20100102}{name}='blah'; $log{54312}{1}{20100101}{name}='blah'; $log{14323}{3}{20100103}{name}='blah'; foreach $entry (sort {$log{$cook}{$a}{time} cmp $log{$cook}{$b}{time}} keys %{$log{$cook}}){ ... } Basically, I would have the same array structure in PHP but want to sort like I do above.

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• How do i add all the values of this multidimensional array or turn it into an array by its values.

  - by Tapha

  The array is here: Array ( [0] = 0 ) Array ( [0] = 0 ) Array ( [0] = 1 [1] = 6 [2] = 0 )

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