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• Moving to an arbitrary position in a file in Python

  - by B Rivera

  Let's say that I routinely have to work with files with an unknown, but large, number of lines. Each line contains a set of integers (space, comma, semicolon, or some non-numeric character is the delimiter) in the closed interval [0, R], where R can be arbitrarily large. The number of integers on each line can be variable. Often times I get the same number of integers on each line, but occasionally I have lines with unequal sets of numbers. Suppose I want to go to Nth line in the file and retrieve the Kth number on that line (and assume that the inputs N and K are valid --- that is, I am not worried about bad inputs). How do I go about doing this efficiently in Python 3.1.2 for Windows? I do not want to traverse the file line by line. I tried using mmap, but while poking around here on SO, I learned that that's probably not the best solution on a 32-bit build because of the 4GB limit. And in truth, I couldn't really figure out how to simply move N lines away from my current position. If I can at least just "jump" to the Nth line then I can use .split() and grab the Kth integer that way. The nuance here is that I don't just need to grab one line from the file. I will need to grab several lines: they are not necessarily all near each other, the order in which I get them matters, and the order is not always based on some deterministic function. Any ideas? I hope this is enough information. Thanks!

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• Open txt files from a directory, compare the values, and output the top 15 in PHP

  - by Anon

  Hello, I recently designed a referral game website for the fun of it. There's a simple MySQL user system with a email verification. It's using the UserCake user management system. On top of this i added a php page that the user could give to "victims" that when they visit it they get "infected" and can infect other users or "victims". This page uses GET to get the username from the url. I have a folder that when a user registers it creates a file with 4 digits and then the username. (ex; 0000Username.txt) All the numbers are the same, it's just so that if a user discovers the folder they won't be able to find the files. There is also a txt file in the same format with IPS in the name. (ex; 0000IPSUsername.txt) The file when visited gets the username from the url, then checks if the text file for that username exists. If the username is present in the url, and a valid user it opens the IPS file and adds the IP of the visitor, then opens the user text file, takes the value and adds one to it, and saves. At the end it makes the difference between saying "You are infected, Username has infected (amount) people." or just you have been infected. Now to what i need! I need to add a hi-scores to the website so people can compete to be the one with the most "infections". I thought i could use readdir to get a list of the files and open them with the value in an array, but i need it to also strip the username from the file name. It would be best if it just saves to a text file like "Username | value" because then i can add echo's of the html tags and have it include the file in the page i want it to be one. Many thanks in advance.

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• What is the minimal licensable source code?

  - by Hernán Eche

  Let's suppose I want to "protect" this code about being used without attribution, patenting it, or through any open source licence... #include<stdio.h> int main (void) { int version=2; printf("\r\n.Hello world, ver:(%d).", version); return 0; } It's a little obvious or just a language definition example.. When a source stop being "trivial, banal, commonplace, obvious", and start to be something that you may claim "rights"? Perhaps it depends on who read it, something that could be great geniality for someone that have never programmed, could be just obvious for an expert. It's easy when watching two sources there are 10000 same lines of code, that's a theft.. but that's not always so obvious. How to measure amount of "ownness", it's about creativity? line numbers? complexity? I can't imagine objetive answers for that, only some patches. For example perhaps the complexity, It's not fair to replace "years of engeneering" with "copy and paste". But is there any objetive index for objetive determination of this subject? (In a funny way I imagine this criterion: If the licence is longer than the code, then there is no owner, just to punish not caring storage space and world resources =P)

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• barebones sort algorithm

  - by user309322

  i have been asked to make a simple sort aglorithm to sort a random series of 6 numbers into numerical order. However i have been asked to do this using "Barebones" a theoretical language put forward in the Book Computer Science an overview. Some information on the language can be found here http://www.brouhaha.com/~eric/software/barebones/ Just to clarify i am a student teacher and have been doing anaysis on "mini-programing languages" and their uses in a teaching environment, i suggested to my tutor that i look at barebones and asked what sort of exmaple program i should write . He suggested a simple sort algorithm. Now since looking at the language i cant understand how i can do this without using arrays and if statements. The code to swap the value of variables would be while a not 0 do; incr Aux1; decr a; end; while b not 0 do; incr Aux2 decr b end; while Aux1 not 0 do; incr a; decr Aux1; end; while Aux2 not 0 do; incr b; decr Aux2; end; however the language does not provide < or operators

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• Python unicode search not giving correct answer

  - by user1318912

  I am trying to search hindi words contained one line per file in file-1 and find them in lines in file-2. I have to print the line numbers with the number of words found. This is the code: import codecs hypernyms = codecs.open("hindi_hypernym.txt", "r", "utf-8").readlines() words = codecs.open("hypernyms_en2hi.txt", "r", "utf-8").readlines() count_arr = [] for counter, line in enumerate(hypernyms): count_arr.append(0) for word in words: if line.find(word) >=0: count_arr[counter] +=1 for iterator, count in enumerate(count_arr): if count>0: print iterator, ' ', count This is finding some words, but ignoring some others The input files are: File-1: ???? ??????? File-2: ???????, ????-???? ?????-???, ?????-???, ?????_???, ?????_??? ????_????, ????-????, ???????_???? ????-???? This gives output: 0 1 3 1 Clearly, it is ignoring ??????? and searching for ???? only. I have tried with other inputs as well. It only searches for one word. Any idea how to correct this?

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• PHP, MySQL prepared statements - can you use results of execute more than once by calling data_seek(

  - by Carvell Fenton

  Hello, I have a case where I want to use the results of a prepared statement more than once in a nested loop. The outer loop processes the results of another query, and the inner loop is the results of the prepared statement query. So the code would be something like this (just "pseudoish" to demonstrate the concept): // not showing the outer query, it is just a basic SELECT, not prepared statement // we'll call it $outer_query $obj_array = array(); // going to save objects in this $ids = array(18,19,20); // just example id numbers $query = "SELECT field1, field2 FROM table1 WHERE id=?"; $stmt = $db->prepare($query); foreach ($ids as $id) { $stmt->bind_param("i", $id); $stmt->execute(); $stmt->bind_result($var1, $var2); $stmt->store_result(); // I think I need this for data_seek while ($q1 = $outer_query->fetch_object()) { while ($stmt->fetch()) { if ($q1->field1 == $var1) { // looking for a match $obj = new stdClass(); $obj->var1 = $var1; $obj->var2 = $var2; $obj_array[] = $obj; $stmt->data_seek(0); // reset for outer loop break; // found match, so leave inner } } } } The problem I seem to be experiencing is that the values are not getting bound in the variables as I would expect after the first time I use fetch in the inner loop. Specifically, in one example I ran with 3 ids for the foreach, the first id was processed correctly, the second was processed incorrectly (matches were not found in the inner loop even though they existed), and then the third was processed correctly. Is there something wrong with the prepared statment function calls in the sequence I am doing above, or is this an invalid way to use the results of the prepared statement? Thanks.

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• Why is my panel not positioned correctly even after setting the boundaries?

  - by nutellafella

  I'm trying to make a simple GUI with radio buttons and I grouped them into one panel. I wanted it positioned on the leftmost side so I used the setBounds method. Whatever numbers I put on the parameters, the panel won't move. Are panels not affected by the setBounds method? Or is there another way to position my panel. Here's the snippet of my code: JPanel radioPanel = new JPanel(); radioPanel.setLayout(new GridLayout(3,1)); JRadioButton Rbutton1 = new JRadioButton("Credit Card"); JRadioButton Rbutton2 = new JRadioButton("E-Funds"); JRadioButton Rbutton3 = new JRadioButton("Check"); Rbutton3.setSelected(true); ButtonGroup Bgroup = new ButtonGroup(); Bgroup.add(Rbutton1); Bgroup.add(Rbutton2); Bgroup.add(Rbutton3); radioPanel.add(Rbutton1); radioPanel.add(Rbutton2); radioPanel.add(Rbutton3); radioPanel.setBounds(10,50,50,40); //this is where I'm trying to position the panel with the radio buttons paymentPanel.add(radioPanel); contentPane.add(paymentPanel); //contentPane is the frame contentPane.setVisible(true);

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• Ideas in implenting the following entry form in ASP.NET MVC 2

  - by KiD0M4N

  Hi guys, I have a very simple data entry form to implement. It looks like this: Obviously I have mocked out the actual requirements but the essence is similar. Entering a name and clicking history should bring up a pop up pointing to the url '/student/viewhistory/{name}' Name and age are required fields The sub form (in the mockup) with Class (a drop down, containing the numbers 1 - 10) and Subject (containing A - D, say) form a unique pair of values for which a score is required. So, selecting the Class and Subject, entering a score and clicking on Add should 'add' this record for the student. Then the user should be able to click Save (to persist the entry to the database) or be able to add further (class, subject, score) pairs to the entry. Any ideas how to smartly implement this? (I am coming from a DWH field... so thinking in a stateless manner is slightly foreign to me.) Any help is appreciated. I would imagine a smart use of jQuery would give a easy solution. Regards, Karan

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• How do I make this nested for loop, testing sums of cubes, more efficient?

  - by Brian J. Fink

  I'm trying to iterate through all the combinations of pairs of positive long integers in Java and testing the sum of their cubes to discover if it's a Fibonacci number. I'm currently doing this by using the value of the outer loop variable as the inner loop's upper limit, with the effect being that the outer loop runs a little slower each time. Initially it appeared to run very quickly--I was up to 10 digits within minutes. But now after 2 full days of continuous execution, I'm only somewhere in the middle range of 15 digits. At this rate it may end up taking a whole year just to finish running this program. The code for the program is below: import java.lang.*; import java.math.*; public class FindFib { public static void main(String args[]) { long uLimit=9223372036854775807L; //long maximum value BigDecimal PHI=new BigDecimal(1D+Math.sqrt(5D)/2D); //Golden Ratio for(long a=1;a<=uLimit;a++) //Outer Loop, 1 to maximum for(long b=1;b<=a;b++) //Inner Loop, 1 to current outer { //Cube the numbers and add BigDecimal c=BigDecimal.valueOf(a).pow(3).add(BigDecimal.valueOf(b).pow(3)); System.out.print(c+" "); //Output result //Upper and lower limits of interval for Mobius test: [c*PHI-1/c,c*PHI+1/c] BigDecimal d=c.multiply(PHI).subtract(BigDecimal.ONE.divide(c,BigDecimal.ROUND_HALF_UP)), e=c.multiply(PHI).add(BigDecimal.ONE.divide(c,BigDecimal.ROUND_HALF_UP)); //Mobius test: if integer in interval (floor values unequal) Fibonacci number! if (d.toBigInteger().compareTo(e.toBigInteger())!=0) System.out.println(); //Line feed else System.out.print("\r"); //Carriage return instead } //Display final message System.out.println("\rDone. "); } } Now the use of BigDecimal and BigInteger was delibrate; I need them to get the necessary precision. Is there anything other than my variable types that I could change to gain better efficiency?

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• Fast way to manually mod a number

  - by Nikolai Mushegian

  I need to be able to calculate (a^b) % c for very large values of a and b (which individually are pushing limit and which cause overflow errors when you try to calculate a^b). For small enough numbers, using the identity (a^b)%c = (a%c)^b%c works, but if c is too large this doesn't really help. I wrote a loop to do the mod operation manually, one a at a time: private static long no_Overflow_Mod(ulong num_base, ulong num_exponent, ulong mod) { long answer = 1; for (int x = 0; x < num_exponent; x++) { answer = (answer * num_base) % mod; } return answer; } but this takes a very long time. Is there any simple and fast way to do this operation without actually having to take a to the power of b AND without using time-consuming loops? If all else fails, I can make a bool array to represent a huge data type and figure out how to do this with bitwise operators, but there has to be a better way.

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• Database contents setting themselves to 0

  - by Luis Armando

  I have a Database that contains 4 tables, however I'm using 1 of them which is separated from the others. In this table I have 4 fields which are varchar and the rest are ints (11 other fields), when the users fill up the DB everything gets saved correctly, however it has happened 3 times so far that the database values for the int's reset to 0 without any apparent reason. At first, I thought, it was because those fields (where the numbers should go) were varchars not ints. However since I changed it, it happened again. I've already double checked my code and I have nothing that even updates or inserts a 0 value. Also I'm using codeigniter and active records which protect against SQL injections AND have XSS filtering enabled, could anyone point out something I might be missing or a reason for this to be happening? Also, I'm pretty sure about the answer of this but, is there ANY way to recover some data?? Other than having to ask everyone to fill in everything again.. =/ ** EDIT ** The Storage Engine is MyISAM and Collation is latin1_swedish_ci, Pack Keys are default, for all intents and purposes it's a normal DB

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• Where is the errnos defined? Example linux c/c++ program for i2c.

  - by Johan

  Hi When something goes wrong in a classic linux c/c++ software we have the magic variable errno that gives us a clue on what just went wrong. But where is those errors defined? Let's take a example (it's actually a piece from a Qt app, therefore the qDebug()). if (ioctl(file, I2C_SLAVE, address) < 0) { int err = errno; qDebug() << __FILE__ << __FUNCTION__ << __LINE__ << "Can't set address:" << address << "Errno:" << err << strerror(err); .... The next step is to look at what that errno was so we can decide if we just quit or try to do something about the problem. So we maybe add a if or switch at this point. if (err == 9) { // do something... } else { //do someting else } And my question is where to find the errors that "9" represents? I don't like that kind of magic numbers in my code. /Thanks

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• TransactionRequiredException on OptimisticLockException

  - by João Madureira Pires

  Hi there. I have the following class that generates sequencial Card Numbers. I'm trying to recover from OptimisticLockException, by calling recursively the same method. however, i'm getting TransactionRequiredException. Dows anyone knows how to recover from OptimisticLockException in my case? Thanks a lot in advance @Name("simpleAutoIncrementGenerator") public class SimpleAutoIncrementGenerator extends CardNumberGenerator{ private static final long serialVersionUID = 2869548248468809665L; private int numberOfRetries = 0; @Override public String generateNextNumber(CardInstance cardInstance, EntityManager entityManager) { try{ EntityCard card = (EntityCard)entityManager.find(EntityCard.class, cardInstance.getId()); if(card != null){ String nextNumber = ""; String currentNumber = card.getCurrentCardNumber(); if(currentNumber != null && !currentNumber.isEmpty()){ Long numberToInc = Long.parseLong(currentNumber); numberToInc ++; nextNumber = String.valueOf(numberToInc); card.setCurrentCardNumber(nextNumber); // this is just to cause a OptimisticLock Exception try { Thread.sleep(4000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } entityManager.persist(card); entityManager.flush(); return nextNumber; } } }catch (OptimisticLockException oLE) { System.out.println("\n\n\n\n OptimisticLockException \n\n\n\n"); if(numberOfRetries < CentralizedConfig.CARD_NUMBER_GENERATOR_MAX_TRIES){ numberOfRetries ++; return generateNextNumber(cardInstance,entityManager); } }catch (TransactionRequiredException trE) { System.out.println("\n\n\n\n TransactionRequiredException \n\n\n\n"); if(numberOfRetries < CentralizedConfig.CARD_NUMBER_GENERATOR_MAX_TRIES){ numberOfRetries ++; return generateNextNumber(cardInstance,entityManager); } }catch (StaleObjectStateException e) { System.out.println("\n\n\n\n StaleObjectStateException \n\n\n\n"); if(numberOfRetries < CentralizedConfig.CARD_NUMBER_GENERATOR_MAX_TRIES){ numberOfRetries ++; return generateNextNumber(cardInstance,entityManager); } } return null; } }

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• Animate and form rows, arrays, AS3

  - by VideoDnd

  Question How can I animate and form rows together? Explanation One 'for loop' is for animation, the other 'for loop' is for making rows. I want to understand how to use arrays and create a row of sprite animations. 'for loop' for animation //FRAMES ARRAY //THIS SETS UP MY ANIMATION FOR TIMER EVENT var frames:Array = [ new Frame1(), new Frame2(), new Frame3(), new Frame4(), new Frame5(), new Frame6(), new Frame7(), new Frame8(), new Frame9(), new Frame0(), ]; for each (var frame:Sprite in frames) { addChild(frame); } 'for loop' for rows //THIS MAKES A ROW OF DISPLAY OBJECTS var numberOfClips:Number = 11; var xStart:Number = 0; var yStart:Number = 0; var xVal:Number = xStart; var xOffset:Number = 2; for (var $:Number=0; $<numberOfClips; $++) { //DUDE ARRAY var dude:Array = frames; dude.y = yStart +11; dude.x = xVal +55; xVal = dude.x + dude.width + this.xOffset; } timer var timer:Timer = new Timer(100); timer.addEventListener(TimerEvent.TIMER, countdown); function countdown(event:TimerEvent) { var currentFrame:int = timer.currentCount % frames.length; for (var i:int = 0; i < frames.length; ++i) { frames[i].visible = (i == currentFrame); } } timer.start(); counter experiment My new class I'm working on loops through 10 different display objects that are numbers. For those following, I'm trying to make something like NumbersView.

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• Counting in R data.table

  - by Simon Z.

  I have the following data.table set.seed(1) DT <- data.table(VAL = sample(c(1, 2, 3), 10, replace = TRUE)) VAL 1: 1 2: 2 3: 2 4: 3 5: 1 6: 3 7: 3 8: 2 9: 2 10: 1 Now I want to to perform two tasks: Count the occurrences of numbers in VAL. Count within all rows with the same value VAL (first, second, third occurrence) At the end I want the result VAL COUNT IDX 1: 1 3 1 2: 2 4 1 3: 2 4 2 4: 3 3 1 5: 1 3 2 6: 3 3 2 7: 3 3 3 8: 2 4 3 9: 2 4 4 10: 1 3 3 where COUNT defines task 1. and IDX task 2. I tried to work with which and length using .I: dt[, list(COUNT = length(VAL == VAL[.I]), IDX = which(which(VAL == VAL[.I]) == .I))] but this does not work as .I refers to a vector with the index, so I guess one must use .I[]. Though inside .I[] I again face the problem, that I do not have the row index and I do know (from reading data.table FAQ and following the posts here) that looping through rows should be avoided if possible. So, what's the data.table way?

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• Why can't RB-Tree be a list?

  - by Alex

  Hey everyone. I have a problem with the rb-trees. according to wikipedia, rb-tree needs to follow the following: A node is either red or black. The root is black. (This rule is used in some definitions and not others. Since the root can always be changed from red to black but not necessarily vice-versa this rule has little effect on analysis.) All leaves are black. Both children of every red node are black. Every simple path from a given node to any of its descendant leaves contains the same number of black nodes. As we know, an rb-tree needs to be balanced and has the height of O(log(n)). But, if we insert an increasing series of numbers (1,2,3,4,5...) and theoretically we will get a tree that will look like a list and will have the height of O(n) with all its nodes black, which doesn't contradict the rb-tree properties mentioned above. So, where am I wrong?? thanks.

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• Why doesn't java.lang.Number implement Comparable?

  - by Julien Chastang

  Does anyone know why java.lang.Number does not implement Comparable? This means that you cannot sort Numbers with Collections.sort which seems to me a little strange. Post discussion update: Thanks for all the helpful responses. I ended up doing some more research about this topic. The simplest explanation for why java.lang.Number does not implement Comparable is rooted in mutability concerns. For a bit of review, java.lang.Number is the abstract super-type of AtomicInteger, AtomicLong, BigDecimal, BigInteger, Byte, Double, Float, Integer, Long and Short. On that list, AtomicInteger and AtomicLong to do not implement Comparable. Digging around, I discovered that it is not a good practice to implement Comparable on mutable types because the objects can change during or after comparison rendering the result of the comparison useless. Both AtomicLong and AtomicInteger are mutable. The API designers had the forethought to not have Number implement Comparable because it would have constrained implementation of future subtypes. Indeed, AtomicLong and AtomicInteger were added in Java 1.5 long after java.lang.Number was initially implemented. Apart from mutability, there are probably other considerations here too. A compareTo implementation in Number would have to promote all numeric values to BigDecimal because it is capable of accommodating all the Number sub-types. The implication of that promotion in terms of mathematics and performance is a bit unclear to me, but my intuition finds that solution kludgy.

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• How big can I make an Android application's canvas in terms of pixels?

  - by user279112

  I've determined an estimate of the size of my Android emulator's screen in pixels, although I think its resolution can be changed to other numbers. Quite frankly though that doesn't eliminate the general problem of not knowing how many pixels on each axis I have to work with on my Android applications in general. The main problem I'm trying to solve is this: How do I make sure I don't use a faulty resolution on Android applications if I want to keep things' sizes constant (so that if the application screen shrinks, for instances, objects will still show up just as big - there just won't be as many of them being shown) if I wish to do this with a single universal resolution for each program? Failing that, how do I make sure everything's alright if I try to do everything the same way with maybe a few different pre-set resolutions? Mainly it seems like a relevant question that must be answered before I can come across a complete answer for the general problem is how big can I always make my application in pixels, NOT regarding if and when a user resizes the application's screen to something smaller than the maximum size permitted by the phone and its operating system. I really want to try to keep this simple. If I were doing this for a modern desktop, for instance, I know that if I design the application with a 800x600 canvas, the user can still shrink the application to the point they're not doing themselves any favors, but at least I can basically count on it working right and not being too big for the monitor or something. Is there such a magic resolution for Android, assuming that I'm designing for API levels 3+ (Android 1.5+)? Thanks

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• Wordpress inserting comments via wp_insert_comment()

  - by Cyber Junkie

  Hello all happy holidays! :) I'm trying to insert comments in my wordpress blog via the wp_insert_comment() function. It's for a plugin I'm trying to make. I have this code in my header for testing. It works every time I refresh the page. $agent = $_SERVER['HTTP_USER_AGENT']; $data = array( 'comment_post_ID' => 256, 'comment_author' => 'Dave', 'comment_author_email' => '[email protected]', 'comment_author_url' => 'http://www.someiste.com', 'comment_content' => 'Lorem ipsum dolor sit amet...', 'comment_author_IP' => '127.3.1.1', 'comment_agent' => $agent, 'comment_date' => date('Y-m-d H:i:s'), 'comment_date_gmt' => date('Y-m-d H:i:s'), 'comment_approved' => 1, ); $comment_id = wp_insert_comment($data); It successfully inserts comments into the database. The problem: Comments don't show via the Disqus comment system. I compared table rows and I noticed that user_agent differs. Normal comments use for example, Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv... and Disqus comments use Disqus/1.1(2.61):119598902 numbers are different for each comment. Does anyone know how to insert comments with wp_insert_comment() when Disqus is enabled?

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• How to globalize ASP.NET MVC views (decimal separators in particular)?

  - by Pawel Krakowiak

  I'm working with the NerdDinner sample application and arrived at the section which deals with the Virtual Earth map. The application stores some values for the longitude and latitude. Unfortunately on my system floating point numbers are stored with a comma as the decimal separator, not a dot like in the US. So if I have a latitude of 47.64 it's retrieved and displayed as 47,64. Because that value is passed in a function call to the Virtual Earth API it fails at that point (e.g. JavaScript API expects 47.64, -122.13, but gets 47,64, -122,13). I need to make sure that the application always uses dots. In a WebForms app I would have a common class which overrides the System.Web.UI.Page.InitializeCulture() method and I would be inheriting my pages from that class. I am not sure about how to do the same with MVC. Do I need a customized ViewPage or something? Is there an easy way to solve this? Examples?

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• Silverlight ClientAccessPolicy issue...I think

  - by Terrence

  Fisrt of all I have my ClientAccessPolicy.xml file in the root of my website. If I access my website using the public domain name like this: h t t p://www.mydomain.com and then go to the page where my SL control is, I get the spinning % numbers up until about 98%, then it quits and my SL control does not appear on the page. If I access my website using the machine name (website is at datacenter, we have vpn setup) like this: h t t p://machinename and then go to the page where my SL control is everything works fine. this must be a ClientAccess Policy issue don't your think? Or what DO you thnik the issue is? Thanks in advance. Here is the contents of my ClientAccessPolicy.xml file: <?xml version="1.0" encoding="utf-8" ?> <access-policy> <cross-domain-access> <policy> <allow-from http-request-headers="*"> <domain uri="*" /> </allow-from> <grant-to> <resource path="/" include-subpaths="true" /> </grant-to> </policy> </cross-domain-access> </access-policy>

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• How can I lookup data about a book from its barcode number?

  - by Joel Spolsky

  I'm building the world's simplest library application. All I want to be able to do is scan in a book's UPC (barcode) using a typical scanner (which just types the numbers of the barcode into a field) and then use it to look up data about the book... at a minimum, title, author, year published, and either the Dewey Decimal or Library of Congress catalog number. The goal is to print out a tiny sticker ("spine label") with the card catalog number that I can stick on the spine of the book, and then I can sort the books by card catalog number on the shelves in our company library. That way books on similar subjects will tend to be near each other, for example, if you know you're looking for a book about accounting, all you have to do is find SOME book about accounting and you'll see the other half dozen that we have right next to it which makes it convenient to browse the library. There seem to be lots of web APIs to do this, including Amazon and the Library of Congress. But those are all extremely confusing to me. What I really just want is a single higher level function that takes a UPC barcode number and returns some basic data about the book.

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• Add leading zeros to this javascript countdown script?

  - by eddjedi

  I am using the following countdown script which works great, but I can't figure out how to add leading zeros to the numbers (eg so it displays 09 instead of 9.) Can anybody help me out please? Here's the current script: function countDown(id, end, cur){ this.container = document.getElementById(id); this.endDate = new Date(end); this.curDate = new Date(cur); var context = this; var formatResults = function(day, hour, minute, second){ var displayString = [ '<div class="stat statBig">',day,'</div>', '<div class="stat statBig">',hour,'</div>', '<div class="stat statBig">',minute,'</div>', '<div class="stat statBig">',second,'</div>' ]; return displayString.join(""); } var update = function(){ context.curDate.setSeconds(context.curDate.getSeconds()+1); var timediff = (context.endDate-context.curDate)/1000; // Check if timer expired: if (timediff<0){ return context.container.innerHTML = formatResults(0,0,0,0); } var oneMinute=60; //minute unit in seconds var oneHour=60*60; //hour unit in seconds var oneDay=60*60*24; //day unit in seconds var dayfield=Math.floor(timediff/oneDay); var hourfield=Math.floor((timediff-dayfield*oneDay)/oneHour); var minutefield=Math.floor((timediff-dayfield*oneDay-hourfield*oneHour)/oneMinute); var secondfield=Math.floor((timediff-dayfield*oneDay-hourfield*oneHour-minutefield*oneMinute)); context.container.innerHTML = formatResults(dayfield, hourfield, minutefield, secondfield); // Call recursively setTimeout(update, 1000); }; // Call the recursive loop update(); }

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• strcmp() but with 0-9 AFTER A-Z? (C/C++)

  - by Aaron

  For reasons I completely disagree with but "The Powers (of Anti-Usability) That Be" continue to decree despite my objections, I have a sorting routine which does basic strcmp() compares to sort by its name. It works great; it's hard to get that one wrong. However, at the 11th hour, it's been decided that entries which begin with a number should come AFTER entries which begin with a letter, contrary to the ASCII ordering. They cite the EBCDIC standard has numbers following letters so the prior assumption isn't a universal truth, and I have no power to win this argument... but I digress. Therein lies my problem. I've replaced all appropriate references to strcmp with a new function call nonstd_strcmp, and now need to implement the modifications to accomplish the sort change. I've used a FreeBSD source as my base: http://freebsd.active-venture.com/FreeBSD-srctree/newsrc/libkern/strncmp.c.html if (n == 0) return (0); do { if (*s1 != *s2++) return (*(const unsigned char *)s1 - *(const unsigned char *)(s2 - 1)); if (*s1++ == 0) break; } while (--n != 0); return (0); I guess I might need to take some time away to really think about how it should be done, but I'm sure I'm not the only one who's experienced the brain-deadness of just-before-release spec changes.

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• Insert or Update using Oracle and PL/SQL

  - by Shane

  I have a PL/SQL function that performs an update/insert on an Oracle database that maintains a target total and returns the difference between the existing value and the new value. Here is the code I have so far: FUNCTION calcTargetTotal(accountId varchar2, newTotal numeric ) RETURN number is oldTotal numeric(20,6); difference numeric(20,6); begin difference := 0; begin select value into oldTotal from target_total WHERE account_id = accountId for update of value; if (oldTotal != newTotal) then update target_total set value = newTotal WHERE account_id = accountId difference := newTotal - oldTotal; end if; exception when NO_DATA_FOUND then begin difference := newTotal; insert into target_total ( account_id, value ) values ( accountId, newTotal ); -- sometimes a race condition occurs and this stmt fails -- in those cases try to update again exception when DUP_VAL_ON_INDEX then begin difference := 0; select value into oldTotal from target_total WHERE account_id = accountId for update of value; if (oldTotal != newTotal) then update target_total set value = newTotal WHERE account_id = accountId difference := newTotal - oldTotal; end if; end; end; end; return difference end calcTargetTotal; This works as expected in unit tests with multiple threads never failing. However when loaded on a live system we have seen this fail with a stack trace looking like this: ORA-01403: no data found ORA-00001: unique constraint () violated ORA-01403: no data found The line numbers (which I have removed since they are meaningless out of context) verify that the first update fails due to no data, the insert fail due to uniqueness, and the 2nd update is failing with no data, which should be impossible. From what I have read on other thread a MERGE statement is also not atomic and could suffer similar problems. Does anyone have any ideas how to prevent this from occurring?

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