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  • When should I use $ (and can it always be replaced with parentheses)?

    - by J Cooper
    From what I'm reading, $ is described as "applies a function to its arguments." However, it doesn't seem to work quite like (apply ...) in Lisp, because it's a binary operator, so really the only thing it looks like it does is help to avoid parentheses sometimes, like foo $ bar quux instead of foo (bar quux). Am I understanding it right? Is the latter form considered "bad style"?

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  • Codeigniter: db data in controller

    - by Kevin Brown
    I'm confused about what to do... I'm working on a user's page where they can view certain things only if their supervisor has given them "money" or "credits". I need a simple way to get the person that is their supervisor by doing something like: $data['employer'] = $this->home_model->getEmployees(array('user_id'=>$manager_id)); Basically, get the user information about a person who's user_id matches the manager_id of the currently logged in member. I don't know how to set the variable $manager_id. Additional Information: The current user has an id, and a manager_id. I need the id of the manager. So, I need to grab the manager_id of the logged-in user and find the manager who's user_id is that of the manager_id. What's the process to do this? I can get each individually, but I don't know how to use one to get the other... I know it is confusing, but I'm confused! Thanks for the help!

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  • BlueJ Chpt 4 - Auction Project - How to make removeLot method work after entering a new lot

    - by Ellaine Ryan
    Hi All I am learning Java through BlueJ I would like to add a removeLot method to the Auction Class in BlueJ Chpt 4. This involves also returning the lot with the given number or null if there is no such lot. If you enter , say 5 lots and then use the remove method, this codes removes whichever lot you specify. However if you enter a new lot after using the removeLot method - an internal error message comes up regarding lotnumbering . Any ideas? Thanks Elaine public Lot removeLot(int number) { if((number >= 1) ) { } Lot lot = getLot (number); if(lot !=null) { lots.remove(lot); } return lot; }

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  • Why is "while" loop really needed in Python?

    - by Tomaž Pisanski
    I was told that 95% of all loops in Python are "for" loops. Since "while" loops are clearly more "dangerous" than "for" loops, I would like to know if there are situations in which the use of a "while" loop is essential. For teaching purposes it would be useful to know if there is a systematic way of transforming "while" loops into "for" loops.

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  • Inserting multiple types into an SQLite database with Python

    - by mankoff
    I'm trying to create an SQLite 3 database from Python. I have a few types I'd like to insert into each record: A float, and then 3 groups of n floats, currently a tuple but could be an array or list.. I'm not well-enough versed in Python to understand all the differences. My problem is the INSERT statement. DAS = 12345 lats = (42,43,44,45) lons = (10,11,12,13) times = (1,2,3,4,5,6,7,8,9) import sqlite3 connection = sqlite3.connect("test.db") cursor = connection.cursor() cursor.execute( "create table foo(DAS LONG PRIMARY KEY,lats real(4),lons real(4), times real(9) )" ) I'm not sure what comes next. Something along the lines of: cmd = 'INSERT into foo values (?,?,?,?), ..." cursor.execute(cmd) How should I best build the SQL insert command given this data?

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  • Python and a "time value of money" problem.

    - by jamieb
    (I asked this question earlier today, but I did a poor job of explaining myself. Let me try again) I have a client who is an industrial maintenance company. They sell service agreements that are prepaid 20 hour blocks of a technician's time. Some of their larger customers might burn through that agreement in two weeks while customers with fewer problems might go eight months on that same contract. I would like to use Python to help model projected sales revenue and determine how many billable hours per month that they'll be on the hook for. If each customer only ever bought a single service contract (never renewed) it would be easy to figure sales as monthly_revenue = contract_value * qty_contracts_sold. Billable hours would also be easy: billable_hrs = hrs_per_contract * qty_contracts_sold. However, how do I account for renewals? Assuming that 90% (or some other arbitrary amount) of customers renew, then their monthly revenue ought to grow geometrically. Another important variable is how long the average customer burns through a contract. How do I determine what the revenue and billable hours will be 3, 6, or 12 months from now, based on various renewal and burn rates? I assume that I'd use some type of recursive function but math was never one of my strong points. Any suggestions please? Edit: I'm thinking that the best way to approach this is to think of it as a "time value of money" problem. I've retitled the question as such. The problem is probably a lot more common if you think of "monthly sales" as something similar to annuity payments.

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  • How should I start to play with 3D

    - by MarceloRamires
    I'm a developer for just about 6 months now, and since I enjoy programming I make a couple of little programs. I've startedmaking encripters, calculators, tools, stuff to play with DropBox (hehe), stuff that play with bitmaps, drawing graphics, and even a program to update the MSN display image according to the artwork of the music you're listening yo on iTunes. Now I kind of ran off ideas of programs to deal with information, and I've had an idea: play around with 3d! so I've read a little about it and figured I'd have to have good notions on position and math on point spacial position (which I do, from my 3d modelling experience), but I don't know how to use API's for it, so I've 'simulated' simple 3d with a simple program I've made (it's just a spinning cube, please, first one to open it, comment here stating that it's safe, i've got no reason to harm anyone's pc.) One of my other hobbies is 3d modelling (completly amateur) and I'd like to mix these hobbies together! Here are some questions: 1) What would be a nice 3d development tool for a .NET programmer like me? 2) Is there a way of using 3d models made in 3DS Max ? (I intend on modelling characters) 3) What knowledges should I have in order to render it, and move it areound ? 4) Which API should I use ? NOTE: Not a dupe, I'm asking for directions specific for .NET development possibly using 3ds MAX, and there's no question about it!

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  • Does a C# using statement perform try/finally?

    - by Lirik
    Suppose that I have the following code: private void UpdateDB(QuoteDataSet dataSet, Strint tableName) { using(SQLiteConnection conn = new SQLiteConnection(_connectionString)) { conn.Open(); using (SQLiteTransaction transaction = conn.BeginTransaction()) { using (SQLiteCommand cmd = new SQLiteCommand("SELECT * FROM " + tableName, conn)) { using (SQLiteDataAdapter sqliteAdapter = new SQLiteDataAdapter()) { sqliteAdapter.Update(dataSet, tableName); } } transaction.Commit(); } } } The C# documentation states that with a using statement the object within the scope will be disposed and I've seen several places where it's suggested that we don't need to use try/finally clause. I usually surround my connections with a try/finally, and I always close the connection in the finally clause. Given the above code, is it reasonable to assume that the connection will be closed if there is an exception?

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  • Arithmetic operator confusion

    - by Dusk
    Why I'm getting two different values while using the arithmetic operators for the same value of variables. I've just altered little bit my second program, which is resulted in giving me the different output. Could anyone please tell me why? int number=113; int rot=0; rot=number%10; rot*=100+number/10; System.out.println(rot);//333 int number=113; int rot=0; rot=number%10; rot=rot*100+number/10; System.out.println(rot);//311

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  • Cocoa Drag and Drop, reading back the data

    - by kodai
    Ok, I have a NSOutlineView set up, and I want it to capture PDF's if a pdf is dragged into the NSOutlineView. My first question, I have the following code: [outlineView registerForDraggedTypes:[NSArray arrayWithObjects:NSStringPboardType, NSFilenamesPboardType, nil]]; In all the apple Docs and examples I've seen I've also seen something like MySupportedType being an object registered for dragging. What does this mean? Do I change the code to be: [outlineView registerForDraggedTypes:[NSArray arrayWithObjects:@"pdf", NSStringPboardType, NSFilenamesPboardType, nil]]; Currently I have it set up to recognize drag and drop, and I can even make it spit out the URL of the dragged file once the drag is accepted, however, this leads me to my second question. I want to keep a copy of those PDF's app side. I suppose, and correct me if I'm wrong, that the best way to do this is to grab the data off the clipboard, save it in some persistant store, and that's that. (as apposed to using some sort of copy command and literally copying the file to the app director.) That being said, I'm not sure how to do that. I've the code: - (BOOL)outlineView:(NSOutlineView *)ov acceptDrop:(id <NSDraggingInfo>)info item:(id)item childIndex:(NSInteger)childIndex { NSPasteboard *pboard = [info draggingPasteboard]; NSURL *fileURL; if ( [[pboard types] containsObject:NSURLPboardType] ) { fileURL = [NSURL URLFromPasteboard:pboard]; // Perform operation using the file’s URL } NSData *data = [pboard dataForType:@"NSPasteboardTypePDF"]; But this never actually gets any data. Like I said before, it does get the URL, just not the data. Does anyone have any advise on how to get this going? Thanks so much!

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  • Creating constant in Python

    - by zfranciscus
    Hi, Is there a way to declare a constant in Python. In java I will we can create constant in this manner: public static final String CONST_NAME = "Name"; What is the equivalent of the above java constant declaration in python ? Cheers,

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  • Form is trying to save the login value of the submit button to my DB.

    - by Sergio Tapia
    Here's my Zend code: <?php require_once ('Zend\Form.php'); class Sergio_Form_registrationform extends Zend_Form { public function init(){ /*********************USERNAME**********************/ $username = new Zend_Form_Element_Text('username'); $alnumValidator = new Zend_Validate_Alnum(); $username ->setRequired(true) ->setLabel('Username:') ->addFilter('StringToLower') ->addValidator('alnum') ->addValidator('regex', false, array('/^[a-z]+/')) ->addValidator('stringLength',false,array(6,20)); $this->addElement($username); /*********************EMAIL**********************/ $email = new Zend_Form_Element_Text('email'); $alnumValidator = new Zend_Validate_Alnum(); $email ->setRequired(true) ->setLabel('EMail:') ->addFilter('StringToLower') ->addValidator('alnum') ->addValidator('regex', false, array('/^[a-z]+/')) ->addValidator('stringLength',false,array(6,20)); $this->addElement($email); /*********************PASSWORD**********************/ $password = new Zend_Form_Element_Password('password'); $alnumValidator = new Zend_Validate_Alnum(); $password ->setRequired(true) ->setLabel('Password:') ->addFilter('StringToLower') ->addValidator('alnum') ->addValidator('regex', false, array('/^[a-z]+/')) ->addValidator('stringLength',false,array(6,20)); $this->addElement($password); /*********************NAME**********************/ $name = new Zend_Form_Element_Text('name'); $alnumValidator = new Zend_Validate_Alnum(); $name ->setRequired(true) ->setLabel('Name:') ->addFilter('StringToLower') ->addValidator('alnum') ->addValidator('regex', false, array('/^[a-z]+/')) ->addValidator('stringLength',false,array(6,20)); $this->addElement($name); /*********************LASTNAME**********************/ $lastname = new Zend_Form_Element_Text('lastname'); $alnumValidator = new Zend_Validate_Alnum(); $lastname ->setRequired(true) ->setLabel('Last Name:') ->addFilter('StringToLower') ->addValidator('alnum') ->addValidator('regex', false, array('/^[a-z]+/')) ->addValidator('stringLength',false,array(6,20)); $this->addElement($lastname); /*********************DATEOFBIRTH**********************/ $dateofbirth = new Zend_Form_Element_Text('dateofbirth'); $alnumValidator = new Zend_Validate_Alnum(); $dateofbirth->setRequired(true) ->setLabel('Date of Birth:') ->addFilter('StringToLower') ->addValidator('alnum') ->addValidator('regex', false, array('/^[a-z]+/')) ->addValidator('stringLength',false,array(6,20)); $this->addElement($dateofbirth); /*********************AVATAR**********************/ $avatar = new Zend_Form_Element_File('avatar'); $alnumValidator = new Zend_Validate_Alnum(); $avatar ->setRequired(true) ->setLabel('Please select a display picture:'); $this->addElement($avatar); /*********************SUBMIT**********************/ $this->addElement('submit', 'login', array('label' => 'Login')); } } ?> Here's the code I use to save the values: public function saveforminformationAction(){ $form = new Sergio_Form_registrationform(); $request = $this->getRequest(); //if($request->isPost() && $form->isValid($_POST)){ $data = $form->getValues(); $db = $this->_getParam('db'); $db->insert('user',$data); //} } When trying to save the values, I recieve a ghastly error: Column 'login' not found.

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  • Which quotes does a programmer need?

    - by Masi
    My keyboard only has normal quotes, not the smart ones. I have obversed that I need normal ones in cgi development and the backward ones in AWK/SED. Is there any rule when I should use smart quotes, normal ones and backward ones? Obviously, I need to edit my keyboard layout to get the smart quotes.

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  • Python: Remove items from a list while iterating in Python

    - by xApple
    My problem is simple: I have a long list of elements that I want to iterate through and check every element against a condition. Depending on the outcome of the condition I would like to delete the current element of the list, and continue iterating over it as usual. I have read a few other threads on this matter. Two solutions seam to be proposed. Either make a dictionary out of the list (which implies making a copy of all the data that is already filling all the RAM in my case). Either walk the list in reverse (which breaks the concept of the alogrithm I want to implement). Is there any better or more elegant way than this to do it ? def walk_list(list_of_g): g_index = 0 while g_index < len(list_of_g): g_current = list_of_g[g_index] if subtle_condition(g_current): list_of_g.pop(g_index) else: g_index = g_index + 1

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  • Java: 2-assignments-2-initializations inside for-loop not allowed?

    - by HH
    $ javac MatchTest.java MatchTest.java:7: ')' expected for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: ';' expected for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: ';' expected for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: not a statement for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ MatchTest.java:7: illegal start of expression for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) ^ 5 errors $ cat MatchTest.java import java.util.*; import java.io.*; public class MatchTest { public static void main(String[] args){ String text = "hello0123456789hello0123456789hello1234567890hello3423243423232"; for((int i=-1 && String match="hello"); (i=text.indexOf(match)+1);) System.out.println(i); } }

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  • Iterating over key and value of defaultdict dictionaries

    - by gf
    The following works as expected: d = [(1,2), (3,4)] for k,v in d: print "%s - %s" % (str(k), str(v)) But this fails: d = collections.defaultdict(int) d[1] = 2 d[3] = 4 for k,v in d: print "%s - %s" % (str(k), str(v)) With: Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: 'int' object is not iterable Why? How can i fix it?

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  • Mysql Text Storage?

    - by mii
    I was wondering if you where to have an article or articles with huge amounts of text, what would be better when creating the database structure for the articles text? And why? What will be the advantages or disadvantages if any?. I was thinking of using one of the data types below to hold the articles text for the MySQL database. VARCHAR TEXT MEDIUMTEXT LONGTEXT

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  • User Management: Managing users in user-defined "groups", database schema and logistics

    - by Kevin Brown
    I'm a noob, development wise and logistically-wise. I'm developing a site that lets people take a test... My client wants the ability for a user with the roll/privledge "admin" (a step below a super-admin) to be allowed to create users and only see/edit the users that they create... The users created in that "category" or group need some information that their superior provides. For example, I log in as a "manager", I have the ability to invite people to take the test, and manage those people. Before adding those people, I will have filled out a short survey about myself... Right now, the users that are invited will be asked some of the same questions as the manager. I'd like to cut down the redundancy by using the information put into the database by the manager and apply it to the invited users. How do I set up my database to work with this criterion? I'm a little confused about how to do this! Let me know if I can add more details... (This is a mysql and php app)

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  • How do you setLayoutParams() for an ImageView?

    - by DeadTime
    I want to set the LayoutParams for an ImageView but cant seem to find out the proper way to do it. I can only find documentation in the API for the various ViewGroups, but not an ImageView. Yet the ImageView seems to have this functionality. This code doesn't work... myImageView.setLayoutParams(new ImageView.LayoutParams(30,30)); How do I do it?

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  • Make: how to force make?

    - by HH
    The command $ make all gives errors such as rm: cannot remove '.lambda': No such file or directory so it stops. How can I force-make? Makefile all: make clean make .lambda make .lambda_t make .activity make .activity_t_lambda clean: rm .lambda .lambda_t .activity .activity_t_lambda .lambda: awk '{printf "%.4f \n", log(2)/log(2.71828183)/$$1}' t_year > .lambda .lambda_t: paste .lambda t_year > .lambda_t .activity: awk '{printf "%.4f \n", $$1*2.71828183^(-$$1*$$2)}' .lambda_t > .activity .activity_t_lambda: paste .activity t_year .lambda | sed -e 's@\t@\t\&\t@g' -e 's@$$@\t\\\\@g' | tee > .activity_t_lambda > ../RESULTS/currentActivity.tex

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  • Reading all compile errors in Windows command-line?

    - by ArdillaRoja
    Noob question, apologies. I'm compiling Java in Windows Vista's command-line and have so many syntax errors that some are being pushed off the top (a lot of 'class, interface or enum expected' errors which leads me to believe it's an obvious syntax mistake early on in the code that I can't spot). Does anyone know how I could get it to display those first errors? Thanks in advance for the help.

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