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  • diff between tables

    - by www.yegorov-p.ru
    I have two tables, with the same structure, for example: table "first' with columns 'a','b','c' and table 'second' with the same columns. How to find difference betweet those two tables? Of course, I can make some script on python, that will make set(a)-set(b), but I think there is some way to do it in mysql.

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  • how to send an array of bytes over a TCP connection (java programming)

    - by Mark Roberts
    Can somebody demonstrate how to send an array of bytes over a TCP connection from a sender program to a receiver program in Java. (I'm new to Java programming, and can't seem to find an example of how to do this that shows both ends of the connection (sender and receiver.) If you know of an existing example, maybe you could post the link. (No need to reinvent the wheel.) P.S. This is NOT homework! :-)

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  • Efficient way in Python to add an element to a comma-separated string

    - by ensnare
    I'm looking for the most efficient way to add an element to a comma-separated string while maintaining alphabetical order for the words: For example: string = 'Apples, Bananas, Grapes, Oranges' addition = 'Cherries' result = 'Apples, Bananas, Cherries, Grapes, Oranges' Also, a way to do this but while maintaining IDs: string = '1:Apples, 4:Bananas, 6:Grapes, 23:Oranges' addition = '62:Cherries' result = '1:Apples, 4:Bananas, 62:Cherries, 6:Grapes, 23:Oranges' Sample code is greatly appreciated. Thank you so much.

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  • App logicstics & changes due to scope creep

    - by Kevin Brown
    I started an app that was initially a testing platform--user management, and managers that can view their employees tests. Recently, functionality has been extended (not built yet) to allow users to complete a test in place of an employee--basically adding a record, but no user. I have three tables in use for this: users(contains user info for login/security), profiles (all personal info: address, height, etc.), and survey (contains survey answers for user). How do I extend my application to encompass this functionality with minimal change to the structure? I assume that the best way to do this would be to insert records to the tables profiles and survey, and have no username/password/email? There MUST be a user_id associated b/c the tables are linked through the user_ids...

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  • Blackberry - Disable Save option in BasicEditField ??

    - by chethan
    I am using a basiceditfield to take input from the user to do some simple string search. But if i type a few letters and wish to go back without continuing the search, it automatically asks me whether to save the contents of the field. I don want this to happen. Can i in any way disable the "Changes made!-save-discard-cancel" option in basiceditfield(or any editfield for that matter)????please help!!!

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  • What makes you want to learn Common Lisp? What do you want from it?

    - by JasonFruit
    I'm working on a toolkit (sort of a live-CD Lisp-in-a-Box) for people new to Common Lisp, and I want to make sure it is broadly satisfying. What is attractive to you about Lisp? What do/did/would you need to get you started and keep you interested? What I have so far: SBCL 10.22, Emacs 22.3, SLIME, and LTK bundled together and configured on a Linux live-CD that boots entirely to RAM. I've now released the result of this; it is available at the Thnake website.

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  • is c++ STL algorithms and containers same across platforms and performance?

    - by Abhilash M
    After learning good amount of c++, i'm now into STL containers and algorithms template library, my major concerns are, 1) Is this library same across different platforms like MS, linux n other os? 2) will quality or efficiency of program c++ module decrease with more use of STL containers and algorithms, i think i can't customize it to all needs. 3) Is this template library good to use in linux system programming, kernel modules? 4) lastly can i use this in programming contests, because it relives a lot of coding and pressure off shoulders.

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  • Error in Python's os.walk?

    - by Mike Caron
    The os.walk documentation (http://docs.python.org/library/os.html? highlight=os.walk#os.walk), says I can skip traversing unwanted directories by removing them from the dir list. The explicit example from the docs: import os from os.path import join, getsize for root, dirs, files in os.walk('python/Lib/email'): print root, "consumes", print sum(getsize(join(root, name)) for name in files), print "bytes in", len(files), "non-directory files" if 'CVS' in dirs: dirs.remove('CVS') # don't visit CVS directories I see different behavior (using ActivePython 2.6.2). Namely for the code: >>> for root,dirs,files in os.walk(baseline): ... if root.endswith(baseline): ... for d in dirs: ... print "DIR: %s" % d ... if not d.startswith("keep_"): ... print "Removing %s\\%s" % (root,d) ... dirs.remove(d) ... ... print "ROOT: %s" % root ... I get the output: DIR: two Removing: two DIR: thr33 Removing: thr33 DIR: keep_me DIR: keep_me_too DIR: keep_all_of_us ROOT: \\mach\dirs ROOT: \\mach\dirs\ONE ROOT: \\mach\dirs\ONE\FurtherRubbish ROOT: \\mach\dirs\ONE\FurtherRubbish\blah ROOT: \\mach\dirs\ONE\FurtherRubbish\blah\Extracted ROOT: \\mach\dirs\ONE\FurtherRubbish\blah2\Extracted\Stuff_1 ... WTF? Why wasn't \\mach\dirs\ONE removed? It clearly doesn't start with "keep_".

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  • Dijkstra's Algorithm explanation java

    - by alchemey89
    Hi, I have found an implementation for dijkstras algorithm on the internet and was wondering if someone could help me understand how the code works. Many thanks private int nr_points=0; private int[][]Cost; private int []mask; private void dijkstraTSP() { if(nr_points==0)return; //algorithm=new String("Dijkstra"); nod1=new Vector(); nod2=new Vector(); weight=new Vector(); mask=new int[nr_points]; //initialise mask with zeros (mask[x]=1 means the vertex is marked as used) for(int i=0;i<nr_points;i++)mask[i]=0; //Dijkstra: int []dd=new int[nr_points]; int []pre=new int[nr_points]; int []path=new int[nr_points+1]; int init_vert=0,pos_in_path=0,new_vert=0; //initialise the vectors for(int i=0;i<nr_points;i++) { dd[i]=Cost[init_vert][i]; pre[i]=init_vert; path[i]=-1; } pre[init_vert]=0; path[0]=init_vert; pos_in_path++; mask[init_vert]=1; for(int k=0;k<nr_points-1;k++) { //find min. cost in dd for(int j=0;j<nr_points;j++) if(dd[j]!=0 && mask[j]==0){new_vert=j; break;} for(int j=0;j<nr_points;j++) if(dd[j]<dd[new_vert] && mask[j]==0 && dd[j]!=0)new_vert=j; mask[new_vert]=1; path[pos_in_path]=new_vert; pos_in_path++; for(int j=0;j<nr_points;j++) { if(mask[j]==0) { if(dd[j]>dd[new_vert]+Cost[new_vert][j]) { dd[j]=dd[new_vert]+Cost[new_vert][j]; } } } } //Close the cycle path[nr_points]=init_vert; //Save the solution in 3 vectors (for graphical purposes) for(int i=0;i<nr_points;i++) { nod1.addElement(path[i]); nod2.addElement(path[i+1]); weight.addElement(Cost[path[i]][path[i+1]]); } }

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  • Using GA in GUI

    - by AlexT
    Sorry if this isn't clear as I'm writing this on a mobile device and I'm trying to make it quick. I've written a basic Genetic Algorithm with a binary encoding (genes) that builds a fitness value and evolves through several iterations using tournament selection, mutation and crossover. As a basic command-line example it seems to work. The problem I've got is with applying a genetic algorithm within a GUI as I am writing a maze-solving program that uses the GA to find a method through a maze. How do I turn my random binary encoded genes and fitness function (add all the binary values together) into a method to control a bot around a maze? I have built a basic GUI in Java consisting of a maze of labels (like a grid) with the available routes being in blue and the walls being in black. To reiterate my GA performs well and contains what any typical GA would (fitness method, get and set population, selection, crossover, etc) but now I need to plug it into a GUI to get my maze running. What needs to go where in order to get a bot that can move in different directions depending on what the GA says? Rough pseudocode would be great if possible As requested, an Individual is built using a separate class (Indiv), with all the main work being done in a Pop class. When a new individual is instantiated an array of ints represent the genes of said individual, with the genes being picked at random from a number between 0 and 1. The fitness function merely adds together the value of these genes and in the Pop class handles selection, mutation and crossover of two selected individuals. There's not much else to it, the command line program just shows evolution over n generations with the total fitness improving over each iteration. EDIT: It's starting to make a bit more sense now, although there are a few things that are bugging me... As Adamski has suggested I want to create an "Agent" with the options shown below. The problem I have is where the random bit string comes into play here. The agent knows where the walls are and has it laid out in a 4 bit string (i.e. 0111), but how does this affect the random 32 bit string? (i.e. 10001011011001001010011011010101) If I have the following maze (x is the start place, 2 is the goal, 1 is the wall): x 1 1 1 1 0 0 1 0 0 1 0 0 0 2 If I turn left I'm facing the wrong way and the agent will move completely off the maze if it moves forward. I assume that the first generation of the string will be completely random and it will evolve as the fitness grows but I don't get how the string will work within a maze. So, to get this straight... The fitness is the result of when the agent is able to move and is by a wall. The genes are a string of 32 bits, split into 16 sets of 2 bits to show the available actions and for the robot to move the two bits need to be passed with four bits from the agent showings its position near the walls. If the move is to go past a wall the move isn't made and it is deemed invalid and if the move is made and if a new wall is found then the fitness goes up. Is that right?

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  • jQuery: Moving window (or FIFO) type DIV?

    - by Legend
    I have been trying to get this effect for a couple of hours now and I must admit I am failing at it. I am trying to construct a DIV that accepts a particular number of items (say 5), when the 6th item is added, the first item that was aded should be removed (first-in-first-out). The feel should have some kind of a fadeIn and fadeOut. Here's what I managed to write till now: ... //Create a ul element with id 'ulele' and add it to a div ... //Do an ajax call and when an element arrives Hash = ComputeHash(message) if(!$("#" + Hash).exists()) { var element = $("<li></li>").html(message).attr('id', Hash).prependTo("#ulele"); $("#" + Hash).hide().delay(10000 - 1000 * messageNumber).show("slow"); _this.prune("#ulele"); } ... prune: function(divid) { $("#" + divid).children().each( function(i, elemLi) { if(i >= maxMessages) $(this).delay(10000).hide("slow").delay(10000).remove(); } ); } I've tried a couple of variations but the final effect I am getting is not that of a FIFO. The elements disappear instantaneously despite the delay and hide("slow") calls. Anyone has a more straightforward approach?

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  • C++: Templates for static functions?

    - by Rosarch
    I have a static Utils class. I want certain methods to be templated, but not the entire class. How do I do this? This fails: #pragma once #include <string> using std::string; class Utils { private: template<class InputIterator, class Predicate> static set<char> findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); public: static void PrintLine(const string& line, int tabLevel = 0); static string getTabs(int tabLevel); template<class InputIterator, class Predicate> static set<char> Utils::findAll_if(InputIterator begin, InputIterator end, Predicate pred); }; Error: utils.h(10): error C2143: syntax error : missing ';' before '<' utils.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int utils.h(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int utils.h(10): error C2238: unexpected token(s) preceding ';' utils.h(10): error C2988: unrecognizable template declaration/definition utils.h(10): error C2059: syntax error : '<' What am I doing wrong? What is the correct syntax for this? Incidentally, I'd like to templatize the return value, too. So instead of: template<class InputIterator, class Predicate> static set<char> findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); I'd have: template<class return_t, class InputIterator, class Predicate> static return_t findAll_if_rec(InputIterator begin, InputIterator end, Predicate pred, set<char> result); How would I specify that: 1) return_t must be a set of some sort 2) InputIterator must be an iterator 3) InputIterator's type must work with return_t's type. Thanks.

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  • jquery tooltip shows a div's content

    - by bob
    Hello, I want to use either http://onehackoranother.com/projects/jquery/tipsy/ or http://bassistance.de/jquery-plugins/jquery-plugin-tooltip/ and I was wondering if lets say I have a div on my page that has a class 'item_info'. Can I have my tooltip that is created output the div inside the tooltip and formatted properly according to my css? Is there another plugin I should be looking into? Thanks. I hope this is clear enough.

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  • Formula to follow addition of rows

    - by Wayne McCaslin
    New to VBA, please help. I have a range say A2:D10; input causes rows to be added. New entries are being added using NextRow=_. Works perfectly, however, how do I get the formulas in columns C and D to follow each new row being added. I cannot just format entire column due to my sort criteria. Example formula is =IF(ISTEXT($B11),$C$2-$D11,"")

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  • Parallel Assignment operator in Ruby

    - by Bragaadeesh
    Hi, I was going through an example from Programming in Ruby book. This is that example def fib_up_to(max) i1, i2 = 1, 1 # parallel assignment (i1 = 1 and i2 = 1) while i1 <= max yield i1 i1, i2 = i2, i1+i2 end end fib_up_to(100) {|f| print f, " " } The above program simply prints the fibonacci numbers upto 100. Thats fine. My question here is when i replace the parallel assignment with something like this, i1 = i2 i2 = i1+i2 I am not getting the desired output. My question here is, is it advisable to use parallel assignments? (I come from Java background and it feels really wierd to see this type of assignment) One more doubt is : Is parallel assignment an operator?? Thanks

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  • Network Security and Encryption explained in laymen terms

    - by Ehrann Mehdan
    Although I might pretend very well that I known a thing about networks or security and it might help me pass an interview, or fix a bug, I don't really feel I'm fooling anyone. I'm looking for a laymen terms explanation of nowadays network security concepts and solutions. The information is scattered around and I didn't find a resource for "dummies" like me (e.g experienced Java developers that can speak the jargon but have no real clue what it means) Topics I have a weak notion about and want to understand better as a Java developer PGP Public / Private keys RSA / DES SSL and 2 way SSL (keystore / trustore) Protecting against Man in the middle fraud Digital Signature and Certificates Is there a resource out there that really explains it in a way that doesn't require a Cisco certificate / Linux lingo / know what is subnet masking or other plumbing skills?

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  • Efficiently generate a 16-character, alphanumeric string

    - by ensnare
    I'm looking for a very quick way to generate an alphanumeric unique id for a primary key in a table. Would something like this work? def genKey(): hash = hashlib.md5(RANDOM_NUMBER).digest().encode("base64") alnum_hash = re.sub(r'[^a-zA-Z0-9]', "", hash) return alnum_hash[:16] What would be a good way to generate random numbers? If I base it on microtime, I have to account for the possibility of several calls of genKey() at the same time from different instances. Or is there a better way to do all this? Thanks.

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