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  • How do I bind a key to "the function represented by the following key sequence"?

    - by katrielalex
    I'm just starting to learn emacs (woohoo!) and I've been mucking around in my .emacs quite happily. Unfortunately, I don't know Lisp yet, so I'm having issues with the basics. I've already remapped a few keys until I fix my muscle memory: (global-set-key (kbd "<f9>") 'recompile) That's fine. But how can I tell a key to 'simulate pressing several keys'? For instance, I don't know, make <f1> do the same as C-u 2 C-x } (widen buffer by two chars). One way is to look up that C-x } calls shrink-window-horizontally, and do some sort of lambda thing. This is of course the neat and elegant way (how do you do this?). But surely there's a way to define <f1> to send the keystrokes C-u 2 C-x }?

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  • Storing expression template functors

    - by UncaughtException
    Hello guys, at the moment I'm really interested in expression templates and want to code a library for writing and differentiating mathematical functions with a lambda-style syntax. At the moment, I'm able to write (_x * _x)(2); and get the correct result 4. But I would really like to do something like MathFunction f = _x * _x; f(2);, but I don't have any ideas on how to cope with the recursive expression templates on the right side. Is it possible to achieve this without using the 'auto'-Keyword instead of MathFunction or having to make the operator() virtual? Thanks for your help!

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  • What is the best regular expression for validating email addresses?

    - by acrosman
    Over the years I have slowly developed a regular expression that validates MOST email addresses correctly, assuming they don't use an IP address as the server part. Currently the expression is: ^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,4})$ I use this in several PHP programs, and it works most of the time. However, from time to time I get contacted by someone that is having trouble with a site that uses it, and I end up having to make some adjustment (most recently I realized that I wasn't allowing 4-character TLDs). What's the best regular expression you have or have seen for validating emails? I've seen several solutions that use functions that use several shorter expressions, but I'd rather have one long complex expression in a simple function instead of several short expression in a more complex function.

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  • Exclude subexpression from regexec in c++

    - by wyatt
    Suppose I was trying to match the following expression using regex.h in C++, and trying to obtain the subexpressions contained: /^((1|2)|3) (1|2)$/ Suppose it were matched against the string "3 1", the subexpressions would be: "3 1" "3" "1" If, instead it were matched against the string "2 1", the subexpressions would be: "2 1" "2" "2" "1" Which means that, depending on how the first subexpression evaluates, the final one is in a different element in the pmatch array. I realise this particular example is trivial, as I could remove one of the sets of brackets, or grab the last element of the array, but it becomes problematic in more complicated expressions. Suppose all I want are the top-level subexpressions, the ones which aren't subexpressions of other subexpressions. Is there any way to only get them? Or, alternatively, to know how many subexpressions are matched within a subexpression, so that I can traverse the array irrespective of how it evaluates? Thanks

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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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  • Is it possible to refactor this C# if(..) statement?

    - by Pure.Krome
    Hi folks, simple question :- i have the following simple if (..) statements :- if (foo == Animal.Cat || foo == Animal.Dog) { .. } if (baa == 1|| baa == 69) { .. } is it possible to refactor these into something like ... DISCLAIMER: I know this doesn't compile .. but this is sorta what i'm trying to get... if (foo == (Animal.Cat || Animal.Dog)) { .. } if (baa == (1 || 69)) { .. } Cheers :) EDIT I wonder if a lambda expression extension could do this? :P

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  • Express XPath as an expression tree

    - by 47d_
    If I have an XPath query like NodeA/NodeB[@WIDTH and not(@WIDTH="20")] | NodeC[@WIDTH and not(@WIDTH="20")]/NodeD Is there any API available to visualize this XPath query as a stack of atomic expressions, something like (following is generic) Get results of NodeA, call it "first set" Get results of NodeB from "first set" Filter where [@WIDTH and not(@WIDTH="20")] Filter NodeD, call this "node d for B" Get results of NodeC from "first set" Filter where [@WIDTH and not(@WIDTH="20")] Filter NodeD, call this "node d for C" Combine "node d for B" and "node d for C" I am trying to see if we can convert the XPath expression into custom expression which is close to english and vice versa. If no API is available, what would be the best approach? Thanks in advance.

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  • Regex to match a Java method signature

    - by nitesh
    I am having this particular requirement where a method has to be identified by different regular expressions for different components. For example, there need to be a regex for return parameter, one for method name, one for argument type and one for argument name. I was able to come up with an expression till this step as follows - ([^,]+) ([^,]+)\((([^,]+) ([^,]+))\) It works well for a method signature like - ReturnType foo(Arg parameter) The regular expression identifies ReturnType, foo, Arg and parameter separately. Now the problem is that a method can have no/one/multiple arguments separated by commas. I am not able to get a repeating expression for this. Help will be appreciated.

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  • Java splitting string by custom regex match

    - by slikz
    I am completely new to regular expressions so I'm looking for a bit of help here. I am compiling under JDK 1.5 Take this line as an example that I read from standard input: ab:Some string po:bubblegum What I would like to do is split by the two characters and colon. That is, once the line is split and put into a string array, these should be the terms: ab:Some string po:bubblegum I have this regex right now: String[] split = input.split("[..:]"); This splits at the semicolon; what I would like is for it to match two characters and a semicolon, but split at the space before that starts. Is this even possible? Here is the output from the string array: ab Some String po bubblegum I've read about Pattern.compile() as well. Is this something I should be considering?

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  • How do I perform a dynamic select in Linq?

    - by Matt Mangold
    I am trying to figure out how to dynamically specify the properties for my select clause in a linq query. Lets say I have a collection of employee objects. At run time, the end user will be specifying which properties they would like to see for those employees, so I need to be able to dynamically construct my Linq select clause. I have used the dynamic Linq library, but I prefer not to use that, because it requires me to build a string to pass to the select method. I'd like to understand how to do this via Expressions.

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  • Java - Reg. Ex. File Question

    - by aloh
    I'm grabbing lines from a text file and sifting line by line using regular expressions. I'm trying to search for blank lines, meaning nothing or just whitespace. However, what exactly is empty space? I know that whitespace is \s but what is a line that is nothing at all? null (\0)? newline (\n)? I tried the test harness in the Java tutorial to try and test to see what an empty space is but no luck so far.

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  • Not a statement?

    - by abelenky
    I have a simple little code fragment that is frustrating me: HashSet<long> groupUIDs = new HashSet<long>(); groupUIDs.Add(uid)? unique++ : dupes++; At compile time, it generates the error: Only assignment, call, increment, decrement, and new object expressions can be used as a statement HashSet.Add is documented to return a bool, so the ternary (?) operator should work, and this looks like a completely legitimate way to track the number of unique and duplicate items I add to a hash-set. When I reformat it as a if-then-else, it works fine. Can anyone explain the error, and if there is a way to do this as a simple ternary operator?

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  • GLOB_BRACE portability?

    - by Pekka
    In this question, I was made aware of glob()'s GLOB_BRACE option that allows for a limited set of regular expressions when searching for files. This looks just like what I need, but according to the manual, GLOB_BRACE is "not available on some Non-GNU Operating systems." Among those seems to be Solaris. I am building an application that is supposed to be as portable as possible, so I need to check out possible problems as early as possible. Does somebody know of other platforms apart from Solaris where GLOB_BRACE is not supported? How about Mac OS = X for example? It's built on top of a Unix. Is every Unix automatically a "GNU" platform as defined in the manual?

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  • Sed substitution not doing what I want and think it should do

    - by nategoose
    I have am trying to use sed to get some info that is encoded within the path of a file which is passed as a parameter to my script (Bourne sh, if it matters). From this example path, I'd like the result to be 8 PATH=/foo/bar/baz/1-1.8/sing/song I first got the regex close by using sed as grep: echo $PATH | sed -n -e "/^.*\/1-1\.\([0-9][0-9]*\).*/p" This properly recognized the string, so I edited it to make a substitution out of it: echo $PATH | sed -n -e "s/^.*\/1-1\.\([0-9][0-9]*\).*/\1/" But this doesn't produce any output. I know I'm just not seeing something simple, but would really appreciate any ideas about what I'm doing wrong or about other ways to debug sed regular expressions.

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  • mysterious difference between rake test and ruby

    - by standup75
    Here is the mysterious: I have a scope which looks like this (in Image.rb) scope :moderate_all, delegates.where("moderation_flag = #{$moderation_flags[:not_moderated]}") Note that delegates is another scope that I am defining before moderate_all When I leave it like this, I can run my test that checks if an image has been "checked-out" it is not available anymore. I don't put the code of the test, because it does not matter actually. With this code, when I run "rake test" it fails, but if I do "ruby test/unit/image_test.rb" it works! I was thinking I am starting to have a bad day. Then I tried scope :moderate_all, lambda { delegates.where("moderation_flag = #{$moderation_flags[:not_moderated]}") } And "rake test" passes! So my problem is solved, but why?

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  • How to compare two lists with duplicated items in one list?

    - by eladc
    I need to compare list_a against many others. my problem starts when there's a duplicated item in the other lists (two k's in other_b). my goal is to filter out all the lists with the same items (up to three matching items). list_a = ['j','k','a','7'] other_b = ['k', 'j', 'k', 'q'] other_c = ['k','k','9','k'] >>>filter(lambda x: not x in list_a,other_b) ['q'] I need a way that would return ['k', 'q'], because 'k' appears only once in list_a. comparing list_a and other_c with set() isn't good for my purpose since it will return only one element: k. while I need ['k','9','k'] I hope I was clear enough. Thank you

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  • Replace String pattern in Java

    - by Hirantha
    I have the following string "value=\"\\d{4}((((0[1-9])|(1[0-2]))((0[1-9])|([12]\\d)|(3[01]))?)?|(\\-(((0[1-9])|(1[0-2]))(\\-((0[1-9])|([12]\\d)|(3[01])))?)?)?)d{4}" There I want to replace all the occurrences of "{" with NCHAR(0x7B) "}" with NCHAR(0x7D). An the content in-between "{ }" should remain unchanged: Ex: \\d{4} after replacing -> NCHAR(0x7B) 4 NCHAR(0x7D). Is there a way to do this using Regular Expressions in Java?. Anyway, this can be done processing the whole string using string operations.

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  • How do I delete an object from an Entity Framework model without first loading it?

    - by Tomas Lycken
    I am quite sure I've seen the answer to this question somewhere, but as I couldn't find it with a couple of searches on SO or google, I ask it again anyway... In Entity Framework, the only way to delete a data object seems to be MyEntityModel ent = new MyEntityModel(); ent.DeleteObject(theObjectToDelete); ent.SaveChanges(); However, this approach requires the object to be loaded to, in this case, the Controller first, just to delete it. Is there a way to delete a business object referencing only for instance its ID? If there is a smarter way using Linq or Lambda expressions, that is fine too. The main objective, though, is to avoid loading data just to delete it.

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  • How to understand the functional programming code for converting IP string to a number?

    - by zfz
    In a python discusion, I saw a way to convert IP string to a integer in functional progamming way. Here is the Link . The function is implemented in a single line. def ipnumber(ip): return reduce(lambda sum, chunk: sum <<8 | chunk, map(int, ip.split("."))) However, I have few ideas of funcional programming. Could anybody explain the function in detail? I've some knowledg of "map" and "reduce". But I don't konw what "|" and "chunk" mean here? Thanks.

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  • Only strip commas surrounded by numbers in a string

    - by overlook77
    I am using StreamReader to read each line of a CSV file into a string. As I am processing each line, I need to strip out any commas that ONLY are surrounded by other numbers. For example, if the string was: "textfield1", "textfield2", "100.00", "1,070.00" I would need to only take the comma out of "1,070.00" from this entire string, resulting in: "textfield1", "textfield2", "100.00", "1070.00" Each string read from the CSV file can differ in number of fields, length, etc., so I need to use something (Regular Expressions maybe?) that looks at the entire string without hardcoding a location or blanket removal of all commas. Here is the approach I have been trying: StreamReader sr = new StreamReader(strInputFile); string nextLine = sr.ReadLine(); try { while ((nextLine = sr.ReadLine()) != null) { string rawtext = nextLine.Replace("[0-9]"+","+"[0-9]" , "[0-9]"+"[0-9]"); // ....rest of code } } This obviously doesn't work because I don't understand how to do this :) I am new at C# and inexperienced in Regex, so hopefully this is relatively simple.

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  • Interesting or unique types encountered?

    - by user318904
    What is the most strange or unique type you have seen in a programming language? I was thinking the other day about a "random variable", ie whenever it is evaluated it yields a random value from some domain. It would require some runtime trickery. Also I bet there can be some interesting mapping of regular expressions into a type system. It does not necessarily have to be a built in or primitive type, but some random class that implements a domain specific type won't really be interesting just unique.

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  • Show me some cool python list comprehensions

    - by christangrant
    One of the major strengths of python and a few other (functional) programming languages are the list comprehension. They allow programmers to write complex expressions in 1 line. They may be confusing at first but if one gets used to the syntax, it is much better than nested complicated for loops. With that said, please share with me some of the coolest uses of list comprehensions. (By cool, I just mean useful) It could be for some programming contest, or a production system. For example: To do the transpose of a matrix mat >>> mat = [ ... [1, 2, 3], ... [4, 5, 6], ... [7, 8, 9], ... ] >>> [[row[i] for row in mat] for i in [0, 1, 2]] [[1, 4, 7], [2, 5, 8], [3, 6, 9]] Please include a description of the expression and where it was used (if possible).

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  • Regular Expression to Match All Characters after another Regex Match

    - by Anthony Wood
    I know this may sound a little confusing, so I am open to suggestions on renaming the title. Basically I have string such as C:...\Downloads\Folder\SubFolder\SubSubFolder. and I want to return the SubFolder and SubSubFolder only. So far, my Regex looks like (?=\\Downloads\\.*?\\).* which matches Downloads\Folder\SubFolder\SubSubFolder. Does anybody have any Ideas what I am missing???? All the solutions below seem to work (except if you didn't know "Folder"). Potentially a bug with the tool I was using to test the regular expressions.

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  • Haskell: Problems with overloading: Interpreter can´t tell which + to use

    - by Ben
    Hi, I want to make functions Double - Double an instance of the Num typeclass. I want to define the sum of two functions as sum of their images. So I wrote instance Num Function where f + g = (\ x - (f x) + (g x)) Here the compiler complains he can´t tell whether I´m using Prelude.+ or Module.+ in the lambda expression. So I imported Prelude qualified as P and wrote instance Num Function where f + g = (\ x - (f x) P.+ (g x)) This compiles just fine, but when I try to add two functions in GHCi the interpreter complains again he can´t tell whether I´m using Prelude.+ or Module.+. Is there any way I can solve this problem?

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  • Eclipse: The icons in "Display View" are all greyed out

    - by Mark Silberbauer
    The discussion here describes the "display view" in eclipse which allows one to to quickly evaluate java expressions. The thing is, when I open the display view the icons remain greyed out and I can't execute anything. The only icon that isn't is "clear console". The odd thing is, alot of the screenshots on the web show the same behaviour but the people posting about the feature don't mentioned it. There aren't any options in the context sensitive menu either. I'm trying it on a java project. I've tried it in the debug view and I get the same issue. I'll provide a screenshot once my hosting is sorted. I'm using eclipse 3.4.

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