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  • What's the scope of a Python variable declared in an if statement?

    - by froadie
    I'm new to Python, so this is probably a simple scoping question. The following code in a Python file (module) is confusing me slightly: if __name__ == '__main__': x = 1 print x In other languages I've worked in, this code would throw an exception, as the x variable is local to the if statement and should not exist outside of it. But this code executes, and prints 1. Can anyone explain this behavior? Are all variables declared in a module global/available to the entire module?

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  • How do I create a new AnyType[] array?

    - by cb
    Which is the best practice in this situation? I would like an un-initialized array of the same type and length as the original. public static <AnyType extends Comparable<? super AnyType>> void someFunction(AnyType[] someArray) { AnyType[] anotherArray = (AnyType[]) new Comparable[someArray.length]; ...or... AnyType[] anotherArray = (AnyType[]) new Object[someArray.length]; ...some other code... } Thanks, CB

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  • How should I return different types in a method based on the value of a string in Java?

    - by Siracuse
    I'm new to Java and I have come to having the following problem: I have created several classes which all implement the interface "Parser". I have a JavaParser, PythonParser, CParser and finally a TextParser. I'm trying to write a method so it will take either a File or a String (representing a filename) and return the appropriate parser given the extension of the file. Here is some psuedo-code of what I'm basically attempting to do: public Parser getParser(String filename) { String extension = filename.substring(filename.lastIndexOf(".")); switch(extension) { case "py": return new PythonParser(); case "java": return new JavaParser(); case "c": return new CParser(); default: return new TextParser(); } } In general, is this the right way to handle this situation? Also, how should I handle the fact that Java doesn't allow switching on strings? Should I use the .hashcode() value of the strings? I feel like there is some design pattern or something for handling this but it eludes me. Is this how you would do it?

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  • Adding li element only if it not already there?

    - by Legend
    I am constructing an <li> element like this: var element = $("<li></li>") .html(mHTML) .attr('id', "elemid"); I am trying to add this element to a <ul> element only if it doesn't already exist. Any ideas on how to do this? Am I supposed to use contains() to see if the ul element contain the html and then decide? For instance, <ul id="elemul"> <li id="elemli1">Element 1</li> <li id="elemli2">Element 2</li> <li id="elemli3">Element 3</li> </ul> If I try adding Element 1, it should not add it. What should I do if its a longer string (not really long but about 150 characters). Note: I cannot rely on IDs to determine the uniqueness. i.e. I might end up forming something like: <li id="elemli3">Element 1</li> Do I go about using hashmaps?

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  • How to convert list into a string?

    - by PARIJAT
    I have extracted some data from the file and want to write it in the file 2 but the program says 'sequence item 1: expected string, list found', I want to know how I can convert buffer[] i.e. string into sequence, so that it could be saved in file 2. file = open('/ddfs/user/data/k/ktrip_01/hmm.txt','r') file2 = open('/ddfs/user/data/k/ktrip_01/hmm_write.txt','w') buffer = [] rec = file.readlines() for line in rec : field = line.split() print '>',field[0] term = field[0] buffer.append(term) print field[1], field[2], field[6], field[12] term1 = field [1] buffer.append(term1) term2 = field[2] buffer.append[term2] term3 = field[6] buffer.append[term3] term4 = field[12] buffer.append[term4] file2.write(buffer) file.close() file2.close()

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  • array, I/O file and standard deviation (c++)

    - by JohnWong
    double s_deviation(double data[],int cnt, double mean) { int i; double sum= 0; double sdeviation; double x; //x = mean(billy,a_size); for(i=0; i<cnt; i++) { sum += ((data[i]) - (mean)); } sdeviation = sqrt(sum/((double)cnt)); return sdeviation; } When I cout the result from this function, it gave me NaN. I tested the value of (mean) and data[i] using return data[i] and return mean they are valid. when i replaced mean with an actual number, the operation returned a finite number. but with mean as a variable, it produced NaH. I can't see anything wrong with my code at the moment. Again, I am sure mean, data are getting the right number based on those tests. Thank you

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  • returning reference to a vector from a method and using its public members

    - by memC
    dear experts, I have a vector t_vec that stores references to instances of class Too. The code is shown below. In the main , I have a vector t_vec_2 which has the same memory address as B::t_vec. But when I try to access t_vec_2[0].val1 it gives error val1 not declared. Could you please point out what is wrong? Also, if you know of a better way to return a vector from a method, please let me know! Thanks in advance. class Too { public: Too(); ~Too(){}; int val1; }; Too::Too(){ val1 = 10; }; class B { public: vector<Too*> t_vec; Too* t1; vector<Too*>& get_tvec(); B(){t1 = new Too();}; ~B(){delete t1;}; }; vector<Too*>& B::get_tvec(){ t_vec.push_back(t1); return t_vec; } int main(){ B b; b = B(); vector<Too*>& t_vec_2 = b.get_tvec(); // Getting error std::cout << "\n val1 = " << t_vec_2[0].val1; return 0; }

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  • Why can't I access the instance.__class__ attribute in Python?

    - by froadie
    I'm new to Python, and I know I must be missing something pretty simple, but why doesn't this very, very simple code work? class myClass: pass testObject = myClass print testObject.__class__ I get the following error: AttributeError: class myClass has no attribute '__class__' Doesn't every object in Python have a __class__ attribute?

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  • Returning currently displayed index of an array Javascript...

    - by Jeff Kindred
    I have a simple array with x number of items. I am displaying them individually via a link click... I want to update a number that say 1 of 10. when the next one is displayed i want it to display 2 of 10 etc... I have looked all around and my brain is fried right now... I know its simple I just cant get it out. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <title>Page Title</title> <link rel="stylesheet" href="style.css" type="text/css" media="screen" charset="utf-8"/> <script type="text/javascript"> var quotations = new Array() quotations[0]= "1" quotations[1]= "2" quotations[2]= "3" quotations[3]= "4" quotations[4]= "5" quotations[5]= "6" quotations[6]= "7" numQuotes = quotations.length; curQuote = 1; function move( xflip ) { curQuote = curQuote + xflip; if (curQuote > numQuotes) { curQuote = 1 ; } if (curQuote == 0) { curQuote = numQuotes ; } document.getElementById('quotation').innerHTML=quotations[curQuote - 1]; } var curPage = //this is where the current index should go </script> </head> <body> <div id="quotation"> <script type="text/javascript">document.write(quotations[0]);</script> </div> <div> <p><a href="javascript();" onclick="move(-1)">GO back</a> <script type="text/javascript">document.write(curPage + " of " + numQuotes)</script> <a href="javascript();" onclick="move(1)">GO FORTH</a></p> </div> </body> </html>

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  • Filter some words

    - by bob
    I want to filter some reserved word on my title form. $adtitle = sanitize($_POST['title']); $ignore = array('sale','buy','rent'); if(in_array($adtitle, $ignore)) { $_SESSION['ignore_error'] = '<strong>'.$adtitle.'</strong> cannot be use as your title'; header('Location:/submit/'); exit; How to make something like this. If user type Car for sale the sale will detected as reserved keyword. Now my current code only detect single keyword only.

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  • How to use avg function?

    - by Marcelo
    I'm new at php and mysql stuff and i'm trying to use an avg function but i don't know how to. I'm trying to do something like this: mysql_connect(localhost,$username,$password); @mysql_select_db($database) or die ("Did not connect to $database"); mysql_query("AVG(column1) FROM table1 ") or die(mysql_error()); mysql_close(); echo AVG(column1); (Q1)I'd like to see the value printed in the screen, but i'm getting nothing but an error message. How could I print this average on the screen ? (Q2)If I had a column month in my table1, how could I print the averages by the months ? Sorry for any bad English, and thanks for the attention.

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  • Regular Expression Sanitize (PHP)

    - by atif089
    Hello, I would like to sanitize a string in to a URL so this is what I basically need. Everything must be removed except alphanumeric characters and spaces and dashed. Spaces should be converter into dashes. Eg. This, is the URL! must return this-is-the-url Thanks

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  • Model in sub-directory via app_label?

    - by prometheus
    In order to place my models in sub-folders I tried to use the app_label Meta field as described here. My directory structure looks like this: project apps foo models _init_.py bar_model.py In bar_model.py I define my Model like this: from django.db import models class SomeModel(models.Model): field = models.TextField() class Meta: app_label = "foo" I can successfully import the model like so: from apps.foo.models.bar_model import SomeModel However, running: ./manage.py syncdb does not create the table for the model. In verbose mode I do see, however, that the app "foo" is properly recognized (it's in INSTALLED_APPS in settings.py). Moving the model to models.py under foo does work. Is there some specific convention not documented with app_label or with the whole mechanism that prevents this model structure from being recognized by syncdb?

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  • What are the books about Open-Source that everyone interested in should read?

    - by Edu Zamora
    Currently I am working and running my first Open-Source project and though I am quite happy how things are working so far, I have the feeling that a lot of things could be done better. So, what books about Open-Source would you recommend me in order to help filling this gap and making things better every day? What are the books that influenced you the most? I am especially interested in: - How to organize and run an Open-Source project - Best practices - Manage and involve users and developers - How to announce and do the releases - Legal issues

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  • What are good resources for computer graphics basics?

    - by Hanno Fietz
    During Flex programming, I recently ran into several questions (about box models, ways to join lines and misaligning pixels [on doctype]) regarding computer graphics and layout, where I felt that I lacked some basic background on things like concepts like the box model approaches mapping real numbers to a pixel raster (like font anti-aliasing) conventions found across drawing engines, like do you count y coordinates from top or bottom, and why I feel that reading some basic Wikipedia articles, books or tutorials on these subjects might help in phrasing my questions more specifically and debugging my code more systematically. I have repeatedly found myself writing tiny test apps in Flex, just to find out how the APIs do very basic stuff. My assumption would be that if I knew the right vocabulary and some general concepts, I could solve these questions much faster.

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  • foo and _foo - about variables inside a class

    - by kame
    class ClassName(object): """ """ def __init__(self, foo, bar): """ """ self.foo = foo # read-write property self.bar = bar # simple attribute def _set_foo(self, value): self._foo = value def _get_foo(self): return self._foo foo = property(_get_foo, _set_foo) a = ClassName(1,2) #a._set_foo(3) print a._get_foo() When I print a._get_foo() the function _get_foo prints the variable self._foo . But where does it come from? self._foo and self.foo are different, aren't they?

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  • How do I splice a python string programmatically?

    - by Robin Welch
    Very simple question, hopefully. So, in Python you can split up strings using indices as follows: >>> a="abcdefg" >>> print a[2:4] cd but how do you do this if the indices are based on variables? E.g. >>> j=2 >>> h=4 >>> print a[j,h] Traceback (most recent call last): File "<stdin>", line 1, in ? TypeError: string indices must be integers

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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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  • Can someone explain to me why my output is this? And how would I correct my output?

    - by user342231
    /* in this slice of code I get an output of bbb 55 66 77 88 aaa the output I expect and want is bbb 55 66 77 88 bbb because I reassign ss from log[0] to log[1] So my question is why is the output different from what I expect and how do I change it to what I want? */ int w,x,y,z; stringstream ss (stringstream::in | stringstream::out); string word; string log[2]; log[0]="aaa 11 22 33 44"; log[1]="bbb 55 66 77 88"; ss<<log[0]; ss>>word; int k=0; ss>>w>>x>>y>>z; k++; ss<<log[k]; cout<<log[k]<<endl; ss>>word; cout<<word<<endl; return 0;

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  • TB3.0.10: Messages being sent back to me

    - by punkinette64
    Hello, I don't know if this will make any sense to you; but here goes. When I send an email and I get a response, more often than not, in the 'to:' is my email address. However, my email address also ends up in the 'from' column.The 'reply-from' address is nowhere to be found;so I don't have any address with which I can send my reply, as both of them have just my email address. What am I doing wrong here? Is there some set-up in my TOOLOPTIONS set-up incorrectly? The set-up in OPTIONS is pretty difficult to understand and it doesn't offer any 'to' or 'reply-from' choices. This is critical because I just cannot answer my emails because there is no one I can send a reply to. Please, please try to help me. If you have the answer, please email me at: [email protected] Thank you. Blessings. Shiloh

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