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  • Running Python code from Java program, shoudl i be doing this?

    - by Space Rocker
    i have a scenario where i draw a network and set all it's paraments on swing based gui, after that i have to translate this network into a python based script which another framework reads and realize this network in the form of virtual machines. As an example have look here: from mininet.topo import Topo, Node class MyTopo( Topo ): def *__init__*( self, enable_all = True ): super( MyTopo, self ).__init__() Host = 1 Switch = 2 self.add_node( Switch, Node( is_switch=True ) ) self.add_node( Host, Node( is_switch=False ) ) self.add_edge( Host, Switch ) self.enable_all() topos = { 'mytopo': ( lambda: MyTopo() ) } It simply connects a host to a switch and realize this topology on mininet framework. Now for now in order to realize the drawn network on java GUI here is what i am doing: I simply take the information from GUI and creates a new python file like the one above using java code and then run this file in mininet, which works fine somehow. I want to know, is this the correct and robust way how i am doing this or should i be looking further into java-python bridge like scenarios to be more effective or so as to say more professional.

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  • Use 'let' in 'if' expression

    - by demas
    I need a function that works like this: foo :: Integer -> Integer -> [Integer] foo a b = do let result = [] let Coord x y = boo a b if x > 0 let result = result ++ [3] if y > 0 let result = result ++ [5] if x < a let result = result ++ [7] if y < b let result = result ++ [9] result I can not use the guards because the result can have more then one element. But as I see I can not use 'let' in the 'if' expression: all_possible_combinations.hs:41:14: parse error on input `let' How can I check multiple expressions and add new elements in the list? I search not only imperative solution, but the functional one.

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  • C variable decleration on gcc compiler - compile time error.

    - by liv2hak
    Assume the following C variable decleration int *A[10] , B[10][10]; Of the following expressions A[2] A[2][3] B[1] B[2][3] which will not give compile time errors if used as left hand sides of assignment statements in a C program. A) 1,2 and 4 only B) 2,3, and 4 only C) 2 and 4 only D) 4 only I have tried this on a gcc compiler.I assigned the value '0' to all the above variables.Only the third one showed an error.I can't really understand the reason.Can someone please expalin why that is.? Thanks

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  • What is Perl's secret of getting small code do so much?

    - by sak
    I've seen many (code-golf) Perl programs out there and even if I can't read them (Don't know Perl) I wonder how you can manage to get such a small bit of code to do what would take 20 lines in some other programming language. What is the secret of Perl? Is there a special syntax that allows you to do complex tasks in few keystrokes? Is it the mix of regular expressions? I'd like to learn how to write powerful and yet short programs like the ones you know from the code-golf challenges here. What would be the best place to start out? I don't want to learn "clean" Perl - I want to write scripts even I don't understand anymore after a week. If there are other programming languages out there with which I can write even shorter code, please tell me.

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  • Apply function to one element of a list in Python

    - by user189637
    I'm looking for a concise and functional style way to apply a function to one element of a tuple and return the new tuple, in Python. For example, for the following input: inp = ("hello", "my", "friend") I would like to be able to get the following output: out = ("hello", "MY", "friend") I came up with two solutions which I'm not satisfied with. One uses a higher-order function. def apply_at(arr, func, i): return arr[0:i] + [func(arr[i])] + arr[i+1:] apply_at(inp, lambda x: x.upper(), 1) One uses list comprehensions (this one assumes the length of the tuple is known). [(a,b.upper(),c) for a,b,c in [inp]][0] Is there a better way? Thanks!

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  • [Android] How do I load URL that requires login into variable?

    - by bebeTech
    I am trying to port my usage meter from a JavaScript Gadget (win) / Widget (OSX) to Android. Total newbie when comes to JAVA + Eclipse + Android 2.1 SDK. Essentially what I want to do is load a page, pass through a username and password and load the resulting page into a array that I can then run some regular expressions through. My code from JavaScript (I've replace the actual URL with a dummy one) is: xmlhttp.open("post","https://acme.com.au/your_account/index.php?function=login",false); xmlhttp.setRequestHeader("If-Modified-Since", "Sat, 1 Jan 2000 00:00:00 GMT"); xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); xmlhttp.send("check_username=" + username + "&password=" + password); I need to know the Android equivalent to the above please. I've played around with WebView but that loads the page in a web browser which isn't what I want.

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  • Regex expression with leading zero

    - by user1874087
    I'm rather new to regex expressions and need help with a simple expression. I'm using Pentaho for ETL (Replace in String transformation) and I have column values that I need to add leading zeros to and parse out text as part of the database import. So far I have been unable to add the leading zero. The column is called Region and the values are "region 8", "region 10", "region 11". My regex expression is ['Region'] which will eliminate the region text but produces results = "8", "10", "11". I need values to produce "08", "10", "11". So all the single digit numbers must have leading zeros.

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  • Extracting property names from a c# source file

    - by Pete
    I want to parse a c# file. The only thing I want is to determine if it contains a property with a specific name; just a simple true/false response. Or rather, since I'd checking for more than one property in each run, extracting a list of property names could be helpful I thought that I could create an elegant solution using the CodeDomProvider functionality (f# example): use reader = new StreamReader(existingFile) let codeProvider = new CSharpCodeProvider() let codeUnit = codeProvider.Parse(reader) Unfortunately, the Parse function is not implemented for the CSharpCodeProvider. Is there a way to get a CodeCompileUnit from a source file? Or is there another elegant way? (I had hoped to avoid regular expressions on this)?

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  • define method for instance of class

    - by aharon
    Let there be class Example defined as: class Example def initialize(test='hey') self.class.send(:define_method, :say_hello, lambda { test }) end end On calling Example.new; Example.new I get a warning: method redefined; discarding old say_hello. This, I conclude, must be because it defines a method in the actual class (which makes sense, from the syntax). And that, of course, would prove disastrous should there be multiple instances of Example with different values in their methods. Is there a way to create methods just for the instance of a class from inside that instance? Thanks so much.

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  • C# ToDictionary can valueSelector give null?

    - by Trimack
    Hi, I want to make a dictionary out of list in a way, that the list becomes keys and values would be empty. I have following code Dictionary<XmlTest, int?> testBattery = new XmlTests().GetRandomTestBattery(id). ToDictionary(k => k, v => null); But I am getting the error "Cannot convert lambda expression to type System.Collections.Generic.IEqualityComparer' because it is not a delegate type" Any ideas how could I fix it? (I know I could iterate through and fill the dict one element at a time, but I simply want to use something more elegant)

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  • how to add markup to text using JavaScript regex

    - by Richard
    I need to add markup to some text using JavaScript regular expressions. In Python I could do this with: >>> import re >>> re.sub('(banana|apple)', r'<b>{\1}</b>', 'I have 1 banana and 2 apples!') 'I have 1 <b>{banana}</b> and 2 <b>{apple}</b>s!' What is the equivalent in JavaScript? string.replace(regex, newstring) seems to only take a raw string for replacing.

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  • Rewriting usort function because of fatal error (PHP bug)

    - by Lionel
    The two following usort functions throw fatal error Base lambda function for closure not found in our productive environment (PHP 5.4). This seems to be a known PHP bug that should be fixed by now (https://bugs.php.net/bug.php?id=52144), but it still occurs for us. Anyway, we unfortunately don't have time to figure out what's wrong with our PHP configurations etc. We would like to rewrite these two functions without the use of anonymous functions, so that the error doesn't occur anymore. Ordering of a multidimensional array ($array) by value of key "position": usort($array, function($a, $b) { return $a['position'] - $b['position']; }); Ordering of a multidimensional array ($array) according to the order of a second array ($position_order): usort($array, function($a, $b) use($position_order) { return (isset($position_order[$a['ftid']]) ? ($position_order[$a['ftid']] - $position_order[$b['ftid']]) : 1); }); Especially the latter causes some headache, as we don't know how to pass the "outside" array $position_order.

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  • Regular expression match, extracting only wanted segments of string

    - by Ben Carey
    I am trying to extract three segments from a string. As I am not particularly good with regular expressions, I think what I have done could probably be done better... I would like to extract the bold parts of the following string: SOMETEXT: ANYTHING_HERE (Old=ANYTHING_HERE, New=ANYTHING_HERE) Some examples could be: ABC: Some_Field (Old=,New=123) ABC: Some_Field (Old=ABCde,New=1234) ABC: Some_Field (Old=Hello World,New=Bye Bye World) So the above would return the following matches: $matches[0] = 'Some_Field'; $matches[1] = ''; $matches[2] = '123'; So far I have the following code: preg_match_all('/^([a-z]*\:(\s?)+)(.+)(\s?)+\(old=(.+)\,(\s?)+new=(.+)\)/i',$string,$matches); The issue with the above is that it returns a match for each separate segment of the string. I do not know how to ensure the string is the correct format using a regular expression without catching and storing the match if that makes sense? So, my question, if not already clear, how I can retrieve just the segments that I want from the above string?

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  • What are the other new features of C# 4.0, after dynamic and optional parameters?

    - by Abel
    So, C# 4.0 came out yesterday. It introduced the much-debated dynamic keyword, named and optional parameters. Smaller improvements were the implicit ref and recognizing of indexed and default properties on COM methods, contra- and co-variance (really a .NET CLR feature, not C# only) and... Is that really it? Are dynamic and optional/named params the only real improvements to C#? Or did I miss something? Not that I'm complaining, but it seems a bit meager after C# 2.0 (generics) and C# 3.0 (lambda, LINQ). Maybe the language just reached actual maturity?

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  • ASP .NET - What's going on behind an Eval() ?

    - by Amokrane
    Hi, I'm trying to understand how Eval() works for a specific purpose. I'm working on a project I don't really know and I need to read some data and put them in drop down list. These data are already read and are displayed inside an ItemTemplate. I noticed there are read using the Eval() method. Something like: <ItemTemplate> <a href="...=<%# Eval("foo") %>></a> </ItemTemplate> I need to know where Eval is getting these data from in order to discover where I should read them for my drop down list! But I didn't really understand how it works! I know that Eval() evaluates data binding expressions at runtime but where do you think I should take a look at? Thank you

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  • Problem when reading backslash in Prolog

    - by Jerry
    I'm writing a lexer in Prolog which will be used as a part of functional language interpreter. Language spec allows expressions like for example let \x = x + 2; to occur. What I want lexer to do for such input is to "return": [tokLet, tokLambda, tokVar(x), tokEq, tokVar(x), tokPlus, tokNumber(2), tokSColon] and the problem is, that Prolog seems to ignore the \ character and "returns" the line written above except for tokLambda. One approach to solve this would be to somehow add second backslash before/after every occurrence of one in the program code (because everything works fine if I change the original input to let \\x = x + 2;) but I don't really like it. Any ideas?

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  • String Functions in IIS Url Rewrite Module

    - by Nariman
    The IIS URL Rewrite Module ships with 3 built-in functions: * ToLower - returns the input string converted to lower case. * UrlEncode - returns the input string converted to URL-encoded format. This function can be used if the substitution URL in rewrite rule contains special characters (for example non-ASCII or URI-unsafe characters). * UrlDecode - decodes the URL-encoded input string. This function can be used to decode a condition input before matching it against a pattern. The functions can be invoked by using the following syntax: {function_name:any_string} The question is: can this list be extended by introducing a Replace function that's available for changing values within a rewrite rule action or condition? Another way to frame the question: is there any way to do a global replace on a URL coming in using this module? It seems that you're limited to using regular expressions and back-references to construct strings, without a search/replace functionality to replace every X with Y in {REQUEST_URI} before issuing a redirect.

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  • Would it be simply better to use the system's functions rather than use the language?

    - by Nullw0rm
    There are many scenarios where I've questioned PHP's performance with some of its functions, and whether I should build a complex class to handle specific things using its seemingly slow tools. For example, Complex regular expressions with sed and processing with awk would seemingly be exponential in performance rather than making PHP's regular expression and seemingly excessive functions parse and in time manage to finish it. If I were to do a lot of network tasks such as MX lookups/DIGging/retrieving simultaneously I would rather pass it via system() and let the OS handle it itself. There are simply too many functions in PHP, that are inefficient and result in slow pages or can be handled easier by the OS. What are your opinions? Do you think I should do the hard work with the OS in its own/custom functions?

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  • Searching for simple variable names like 'c' or 'x' in Emacs.

    - by wpeters
    I often wish to search for variables that are simply called 'c' or 'count'. For example int c, count; Unfortunately when I use an incremental search for 'c' or 'count' I get a lot of unnecessary hits like the 'c' in 'choice', or the 'count' in 'wordcount' which do not interest me. I know Emacs can do i-searches with regular expressions but I don't know the correct regular expression needed to match just 'c' and 'count'. These words are often surrounded by any number of white spaces. Anyone know the regex I can use to narrow my search?

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  • Select records from XML column (SQL Server 2005) based on node order

    - by jdoe
    I have a column in a SQL Server 2005 table defined as an XML column. Is there a way to select records from this table based on the order of two nodes in that column? For example, we have the following structure in our XML: <item> <latitude/> <longitude/> </item> I want to see if there are any records that have latitude/longitude in the opposite order i.e. <longitude/> then <latitude/>. I've tried some XPath expressions but with no luck.

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  • Is it possible to "learn" a regular expression by user-provided examples?

    - by DR
    Is it possible to "learn" a regular expression by user-provided examples? To clarify: I do not want to learn regular expressions. I want to create a program which "learns" a regular expression from examples which are interactively provided by a user, perhaps by selecting parts from a text or selecting begin or end markers. Is it possible? Are there algorithms, keywords, etc. which I can Google for? EDIT: Thank you for the answers, but I'm not interested in tools which provide this feature. I'm looking for theoretical information, like papers, tutorials, source code, names of algorithms, so I can create something for myself.

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  • Using Rails and Rspec, how do you test that the database is not touched by a method

    - by Will Tomlins
    So I'm writing a test for a method which for performance reasons should achieve what it needs to achieve without using SQL queries. I'm thinking all I need to know is what to stub: describe SomeModel do describe 'a_getter_method' do it 'should not touch the database' do thing = SomeModel.create something_inside_rails.should_not_receive(:a_method_querying_the_database) thing.a_getter_method end end end EDIT: to provide a more specific example: class Publication << ActiveRecord::Base end class Book << Publication end class Magazine << Publication end class Student << ActiveRecord::Base has_many :publications def publications_of_type(type) #this is the method I am trying to test. #The test should show that when I do the following, the database is queried. self.publications.find_all_by_type(type) end end describe Student do describe "publications_of_type" do it 'should not touch the database' do Student.create() student = Student.first(:include => :publications) #the publications relationship is already loaded, so no need to touch the DB lambda { student.publications_of_type(:magazine) }.should_not touch_the_database end end end So the test should fail in this example, because the rails 'find_all_by' method relies on SQL.

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  • IIS7: URL Rewrite - can it be used to hide a CDN path?

    - by Wild Thing
    Hi, I am using Rackspace Cloud CDN (Limelight CDN) for my website. The URLs of the CDN are in the format http://cxxxxxx.cdn.cloudfiles.rackspacecloud.com/something.jpg My domain is mydomain.com. Can I use IIS URL rewriting to show http://cxxxxxx.cdn.cloudfiles.rackspacecloud.com/something.jpg as http://images.mydomain.com/something.jpg? Or is this impossible without the CDN setup accepting my CNAME? If so, can you please help create the URL rewrite rule? (Sorry, don't know how to use regular expressions) Thanks, WT

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  • BASH Expression to replace beginning and ending of a string in one operation?

    - by swestrup
    Here's a simple problem that's been bugging me for some time. I often find I have a number of input files in some directory, and I want to construct output file names by replacing beginning and ending portions. For example, given this: source/foo.c source/bar.c source/foo_bar.c I often end up writing BASH expressions like: for f in source/*.c; do a="obj/${f##*/}" b="${a%.*}.obj" process "$f" "$b" done to generate the commands process "source/foo.c" "obj/foo.obj" process "source/bar.c "obj/bar.obj" process "source/foo_bar.c "obj/foo_bar.obj" The above works, but its a lot wordier than I like, and I would prefer to avoid the temporary variables. Ideally there would be some command that could replace the beginning and ends of a string in one shot, so that I could just write something like: for f in source/*.c; do process "$f" "obj/${f##*/%.*}.obj"; done Of course, the above doesn't work. Does anyone know something that will? I'm just trying to save myself some typing here.

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  • Is there an easy way in Python to wait until certain condition is true?

    - by Checkers
    I need to wait in a script until a certain number of conditions become true? I know I can roll my own eventing using condition variables and friends, but I don't want to go through all the trouble of implementing it, since some object property changes come from external thread in a wrapped C++ library (Boost.Python), so I can't just hijack __setattr__ in a class and put a condition variable there, which leaves me with either trying to create and signal a Python condition variable from C++, or wrap a native one and wait on it in Python, both of which sound fiddly, needlessly complicated and boring. Is there an easier way to do it, barring continuous polling of the condition? Ideally it would be along the lines of res = wait_until(lambda: some_predicate, timeout) if (not res): print 'timed out'

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