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  • Excel Regex, or export to Python? ; "Vlookup" in Python?

    - by victorhooi
    heya, We have an Excel file with a worksheet containing people records. 1. Phone Number Sanitation One of the fields is a phone number field, which contains phone numbers in the format e.g.: +XX(Y)ZZZZ-ZZZZ (where X, Y and Z are integers). There are also some records which have less digits, e.g.: +XX(Y)ZZZ-ZZZZ And others with really screwed up formats: +XX(Y)ZZZZ-ZZZZ / ZZZZ or: ZZZZZZZZ We need to sanitise these all into the format: 0YZZZZZZZZ (or OYZZZZZZ with those with less digits). 2. Fill in Supervisor Details Each person also has a supervisor, given as an numeric ID. We need to do a lookup to get the name and email address of that supervisor, and add it to the line. This lookup will be firstly on the same worksheet (i.e. searching itself), and it can then fallback to another workbook with more people. 3. Approach? For the first issue, I was thinking of using regex in Excel/VBA somehow, to do the parsing. My Excel-fu isn't the best, but I suppose I can learn...lol. Any particular points on this one? However, would I be better off exporting the XLS to a CSV (e.g. using xlrd), then using Python to fix up the phone numbers? For the second approach, I was thinking of just using vlookups in Excel, to pull in the data, and somehow, having it fall through, first on searching itself, then on the external workbook, then just putting in error text. Not sure how to do that last part. However, if I do happen to choose to export to CSV and do it in Python, what's an efficient way of doing the vlookup? (Should I convert to a dict, or just iterate? Or is there a better, or more idiomatic way?) Cheers, Victor

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  • Django model operating on a queryset

    - by jmoz
    I'm new to Django and somewhat to Python as well. I'm trying to find the idiomatic way to loop over a queryset and set a variable on each model. Basically my model depends on a value from an api, and a model method must multiply one of it's attribs by this api value to get an up-to-date correct value. At the moment I am doing it in the view and it works, but I'm not sure it's the correct way to achieve what I want. I have to replicate this looping elsewhere. Is there a way I can encapsulate the looping logic into a queryset method so it can be used in multiple places? I have this atm (I am using django-rest-framework): class FooViewSet(viewsets.ModelViewSet): model = Foo serializer_class = FooSerializer bar = # some call to an api def get_queryset(self): # Dynamically set the bar variable on each instance! foos = Foo.objects.filter(baz__pk=1).order_by('date') for item in foos: item.needs_bar = self.bar return items I would think something like so would be better: def get_queryset(self): bar = # some call to an api # Dynamically set the bar variable on each instance! return Foo.objects.filter(baz__pk=1).order_by('date').set_bar(bar) I'm thinking the api hit should be in the controller and then injected to instances of the model, but I'm not sure how you do this. I've been looking around querysets and managers but still can't figure it out nor decided if it's the best method to achieve what I want. Can anyone suggest the correct way to model this with django? Thanks.

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  • Binary search in a sorted (memory-mapped ?) file in Java

    - by sds
    I am struggling to port a Perl program to Java, and learning Java as I go. A central component of the original program is a Perl module that does string prefix lookups in a +500 GB sorted text file using binary search (essentially, "seek" to a byte offset in the middle of the file, backtrack to nearest newline, compare line prefix with the search string, "seek" to half/double that byte offset, repeat until found...) I have experimented with several database solutions but found that nothing beats this in sheer lookup speed with data sets of this size. Do you know of any existing Java library that implements such functionality? Failing that, could you point me to some idiomatic example code that does random access reads in text files? Alternatively, I am not familiar with the new (?) Java I/O libraries but would it be an option to memory-map the 500 GB text file (I'm on a 64-bit machine with memory to spare) and do binary search on the memory-mapped byte array? I would be very interested to hear any experiences you have to share about this and similar problems.

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  • How to mimic built-in .NET serialization idioms?

    - by Matt Enright
    I have a library (written in C#) for which I need to read/write representations of my objects to disk (or to any Stream) in a particular binary format (to ensure compatibility with C/Java library implementations). The format requires a fair amount of bit-packing and some DEFLATE'd bytestreams. I would like my library, however, to be as idiomatic .NET as possible, however, and so would like to provide an API as close as possible to the normal binary serialization process. I'm aware of the ability to implement the IFormatter interface, but being that I really am unable to reuse any part of the built-in serialization stack, is it worth doing this, or will it just bring unnecessary overhead. In other words: Implement IFormatter and co. OR Just provide "Serialize"/"Deserialize" methods that act on a Stream? A good point brought up below about needing the serialization semantics for any case involving Remoting. In a case where using MarshalByRef objects is feasible, I'm pretty sure that this won't be an issue, so leaving that aside are there any benefits or drawbacks to using the ISerializable/IFormatter versus a custom stack (or, is my understanding remoting incorrectly)?

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  • Haskell math performance

    - by Travis Brown
    I'm in the middle of porting David Blei's original C implementation of Latent Dirichlet Allocation to Haskell, and I'm trying to decide whether to leave some of the low-level stuff in C. The following function is one example—it's an approximation of the second derivative of lgamma: double trigamma(double x) { double p; int i; x=x+6; p=1/(x*x); p=(((((0.075757575757576*p-0.033333333333333)*p+0.0238095238095238) *p-0.033333333333333)*p+0.166666666666667)*p+1)/x+0.5*p; for (i=0; i<6 ;i++) { x=x-1; p=1/(x*x)+p; } return(p); } I've translated this into more or less idiomatic Haskell as follows: trigamma :: Double -> Double trigamma x = snd $ last $ take 7 $ iterate next (x' - 1, p') where x' = x + 6 p = 1 / x' ^ 2 p' = p / 2 + c / x' c = foldr1 (\a b -> (a + b * p)) [1, 1/6, -1/30, 1/42, -1/30, 5/66] next (x, p) = (x - 1, 1 / x ^ 2 + p) The problem is that when I run both through Criterion, my Haskell version is six or seven times slower (I'm compiling with -O2 on GHC 6.12.1). Some similar functions are even worse. I know practically nothing about Haskell performance, and I'm not terribly interested in digging through Core or anything like that, since I can always just call the handful of math-intensive C functions through FFI. But I'm curious about whether there's low-hanging fruit that I'm missing—some kind of extension or library or annotation that I could use to speed up this numeric stuff without making it too ugly.

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  • Appending and prepending to XML files with Clojure

    - by Isaac Copper
    I have an XML file with format similar to: <root> <baby> <a>stuff</a> <b>stuff</b> <c>stuff</c> </baby> ... <baby> <a>stuff</a> <b>stuff</b> <c>stuff</c> </baby> </root> And a Clojure hash-map similar to: {:a "More stuff" :b "Some other stuff" :c "Yet more of that stuff"} And I'd like to prepend XML (¶) created from this hash-map after the <root> tag and before the first <baby> (¶) The XML to prepend would be like: <baby> <a>More stuff</a> <b>Some other stuff</b> <c>Yet more of that stuff</c> </baby> I'd also like to be able to delete the last one (or n...) <baby>...</baby>s from the file. I'm struggling with coming up with an idiomatic was to prepend and append this data. I can do raw string manipulations, or parse the XML using xml/parse and xml-seq and then roll through the nodes and (somehow?) replace the data there, but that seems messy. Any tips? Ideas? Hints? Pointers? They'd all be much appreciated. Thank you!

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  • Reuse, Rewrite, or Refactor?

    - by Jon Purdy
    At work I inherited development of a PHP-based Web site after the consultant who originally produced it bailed out and left without a trace. Literally half of the code is ripped from online tutorials, and there are thousands of lines of cruft that, being incomplete, do precious little. Hardly any of it actually works. I've been trying to pull out the usable components, such as the layout (cleverly intermixed with code), session management (delicately seasoned with unescaped, unvalidated SQL queries), and a few other things, but it's very difficult to force all of this junk into place. Further, I don't speak idiomatic PHP, being more of a Perl user, and I'm supposed to be on this project principally for maintenance, so rewriting everything seems like it would take just as long as wrestling the existing monster back into place. As an aside, I have literally never seen anything as badly written as this. Welcome me to the world of working with other people's code, I guess, but I do hope it's not this common in the real world to have such gems as these: // WHY IS THIS NOT WORKING // I know this is bad but were going for working stuff right now... // This is a PHP code outputing Javascript code outputting HTML...do not go further // Not userful I'm looking for the best advice I can get here. What would you do if you were in my position?

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  • How can I generate the Rowland prime sequence idiomatically in J?

    - by Gregory Higley
    If you're not familiar with the Rowland prime sequence, you can find out about it here. I've created an ugly, procedural monadic verb in J to generate the first n terms in this sequence, as follows: rowland =: monad define result =. 0 $ 0 t =. 1 $ 7 while. (# result) < y do. a =. {: t n =. 1 + # t t =. t , a + n +. a d =. | -/ _2 {. t if. d > 1 do. result =. ~. result , d end. end. result ) This works perfectly, and it indeed generates the first n terms in the sequence. (By n terms, I mean the first n distinct primes.) Here is the output of rowland 20: 5 3 11 23 47 101 7 13 233 467 941 1889 3779 7559 15131 53 30323 60647 121403 242807 My question is, how can I write this in more idiomatic J? I don't have a clue, although I did write the following function to find the differences between each successive number in a list of numbers, which is one of the required steps. Here it is, although it too could probably be refactored by a more experienced J programmer than I: diffs =: monad : '}: (|@({.-2&{.) , $:@}.) ^: (1 < #) y'

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  • Java try finally variations

    - by Petr Gladkikh
    This question nags me for a while but I did not found complete answer to it yet (e.g. this one is for C# http://stackoverflow.com/questions/463029/initializing-disposable-resources-outside-or-inside-try-finally). Consider two following Java code fragments: Closeable in = new FileInputStream("data.txt"); try { doSomething(in); } finally { in.close(); } and second variation Closeable in = null; try { in = new FileInputStream("data.txt"); doSomething(in); } finally { if (null != in) in.close(); } The part that worries me is that the thread might be somewhat interrupted between the moment resource is acquired (e.g. file is opened) but resulting value is not assigned to respective local variable. Is there any other scenarios the thread might be interrupted in the point above other than: InterruptedException (e.g. via Thread#interrupt()) or OutOfMemoryError exception is thrown JVM exits (e.g. via kill, System.exit()) Hardware fail (or bug in JVM for complete list :) I have read that second approach is somewhat more "idiomatic" but IMO in the scenario above there's no difference and in all other scenarios they are equal. So the question: What are the differences between the two? Which should I prefer if I do concerned about freeing resources (especially in heavily multi-threading applications)? Why? I would appreciate if anyone points me to parts of Java/JVM specs that support the answers.

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  • Trouble with building up a string in Clojure

    - by Aki Iskandar
    Hi gang - [this may seem like my problem is with Compojure, but it isn't - it's with Clojure] I've been pulling my hair out on this seemingly simple issue - but am getting nowhere. I am playing with Compojure (a light web framework for Clojure) and I would just like to generate a web page showing showing my list of todos that are in a PostgreSQL database. The code snippets are below (left out the database connection, query, etc - but that part isn't needed because specific issue is that the resulting HTML shows nothing between the <body> and </body> tags). As a test, I tried hard-coding the string in the call to main-layout, like this: (html (main-layout "Aki's Todos" "Haircut<br>Study Clojure<br>Answer a question on Stackoverfolw")) - and it works fine. So the real issue is that I do not believe I know how to build up a string in Clojure. Not the idiomatic way, and not by calling out to Java's StringBuilder either - as I have attempted to do in the code below. A virtual beer, and a big upvote to whoever can solve it! Many thanks! ============================================================= ;The master template (a very simple POC for now, but can expand on it later) (defn main-layout "This is one of the html layouts for the pages assets - just like a master page" [title body] (html [:html [:head [:title title] (include-js "todos.js") (include-css "todos.css")] [:body body]])) (defn show-all-todos "This function will generate the todos HTML table and call the layout function" [] (let [rs (select-all-todos) sbHTML (new StringBuilder)] (for [rec rs] (.append sbHTML (str rec "<br><br>"))) (html (main-layout "Aki's Todos" (.toString sbHTML))))) ============================================================= Again, the result is a web page but with nothing between the body tags. If I replace the code in the for loop with println statements, and direct the code to the repl - forgetting about the web page stuff (ie. the call to main-layout), the resultset gets printed - BUT - the issue is with building up the string. Thanks again. ~Aki

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  • Indenting Paragraph With cout

    - by Eric
    Given a string of unknown length, how can you output it using cout so that the entire string displays as an indented block of text on the console? (so that even if the string wraps to a new line, the second line would have the same level of indentation) Example: cout << "This is a short string that isn't indented." << endl; cout << /* Indenting Magic */ << "This is a very long string that will wrap to the next line because it is a very long string that will wrap to the next line..." << endl; And the desired output: This is a short string that isn't indented. This is a very long string that will wrap to the next line because it is a very long string that will wrap to the next line... Edit: The homework assignment I'm working on is complete. The assignment has nothing to do with getting the output to format as in the above example, so I probably shouldn't have included the homework tag. This is just for my own enlightment. I know I could count through the characters in the string, see when I get to the end of a line, then spit out a newline and output -x- number of spaces each time. I'm interested to know if there is a simpler, idiomatic C++ way to accomplish the above.

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  • Project Euler #14 and memoization in Clojure

    - by dbyrne
    As a neophyte clojurian, it was recommended to me that I go through the Project Euler problems as a way to learn the language. Its definitely a great way to improve your skills and gain confidence. I just finished up my answer to problem #14. It works fine, but to get it running efficiently I had to implement some memoization. I couldn't use the prepackaged memoize function because of the way my code was structured, and I think it was a good experience to roll my own anyways. My question is if there is a good way to encapsulate my cache within the function itself, or if I have to define an external cache like I have done. Also, any tips to make my code more idiomatic would be appreciated. (use 'clojure.test) (def mem (atom {})) (with-test (defn chain-length ([x] (chain-length x x 0)) ([start-val x c] (if-let [e (last(find @mem x))] (let [ret (+ c e)] (swap! mem assoc start-val ret) ret) (if (<= x 1) (let [ret (+ c 1)] (swap! mem assoc start-val ret) ret) (if (even? x) (recur start-val (/ x 2) (+ c 1)) (recur start-val (+ 1 (* x 3)) (+ c 1))))))) (is (= 10 (chain-length 13)))) (with-test (defn longest-chain ([] (longest-chain 2 0 0)) ([c max start-num] (if (>= c 1000000) start-num (let [l (chain-length c)] (if (> l max) (recur (+ 1 c) l c) (recur (+ 1 c) max start-num)))))) (is (= 837799 (longest-chain))))

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  • Modified map2 (without truncation of lists) in F# - how to do it idiomatically?

    - by Maciej Piechotka
    I'd like to rewrite such function into F#: zipWith' :: (a -> b -> c) -> (a -> c) -> (b -> c) -> [a] -> [b] -> [c] zipWith' _ _ h [] bs = h `map` bs zipWith' _ g _ as [] = g `map` as zipWith' f g h (a:as) (b:bs) = f a b:zipWith f g h as bs My first attempt was: let inline private map2' (xs : seq<'T>) (ys : seq<'U>) (f : 'T -> 'U -> 'S) (g : 'T -> 'S) (h : 'U -> 'S) = let xenum = xs.GetEnumerator() let yenum = ys.GetEnumerator() seq { let rec rest (zenum : IEnumerator<'A>) (i : 'A -> 'S) = seq { yield i(zenum.Current) if zenum.MoveNext() then yield! (rest zenum i) else zenum.Dispose() } let rec merge () = seq { if xenum.MoveNext() then if yenum.MoveNext() then yield (f xenum.Current yenum.Current); yield! (merge ()) else yenum.Dispose(); yield! (rest xenum g) else xenum.Dispose() if yenum.MoveNext() then yield! (rest yenum h) else yenum.Dispose() } yield! (merge ()) } However it can hardly be considered idiomatic. I heard about LazyList but I cannot find it anywhere.

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  • Use properties or methods to expose business rules in C#?

    - by Val
    I'm writing a class to encapsulate some business rules, each of which is represented by a boolean value. The class will be used in processing an InfoPath form, so the rules get the current program state by looking up values in a global XML data structure using XPath operations. What's the best (most idiomatic) way to expose these rules to callers -- properties or public methods? Call using properties Rules rules = new Rules(); if ( rules.ProjectRequiresApproval ) { // get approval } else { // skip approval } Call using methods Rules rules = new Rules(); if ( rules.ProjectRequiresApproval() ) { // get approval } else { // skip approval } Rules class exposing rules as properties public class Rules() { private int _amount; private int threshold = 100; public Rules() { _amount = someExpensiveXpathOperation; } // rule property public bool ProjectRequiresApproval { get { return _amount < threshold } } } Rules class exposing rules as methods public class Rules() { private int _amount; private int threshold = 100; public Rules() { _amount = someExpensiveXpathOperation; } // rule method public bool ProjectRequiresApproval() { return _amount < threshold; } } What are the pros and cons of one over the other?

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  • accessing private variable from member function in PHP

    - by Carson Myers
    I have derived a class from Exception, basically like so: class MyException extends Exception { private $_type; public function type() { return $this->_type; //line 74 } public function __toString() { include "sometemplate.php"; return ""; } } Then, I derived from MyException like so: class SpecialException extends MyException { private $_type = "superspecial"; } If I throw new SpecialException("bla") from a function, catch it, and go echo $e, then the __toString function should load a template, display that, and then not actually return anything to echo. This is basically what's in the template file <div class="<?php echo $this->type(); ?>class"> <p> <?php echo $this->message; ?> </p> </div> in my mind, this should definitely work. However, I get the following error when an exception is thrown and I try to display it: Fatal error: Cannot access private property SpecialException::$_type in C:\path\to\exceptions.php on line 74 Can anyone explain why I am breaking the rules here? Am I doing something horribly witty with this code? Is there a much more idiomatic way to handle this situation? The point of the $_type variable is (as shown) that I want a different div class to be used depending on the type of exception caught.

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  • Are there any code critique sites or similar resources?

    - by Ukko
    I have noticed when people post example code illustrating some issue that they are having often they will gather a number of comments addressing the quality of the code they presented and not the actual problem asked. This is very helpful--if not well directed. Often, this is wasted effort since the asker is often not receptive and the code is often chopped down to something small to post leaving lots of rough edges. In the old days you would see people asking questions like this on comp.lang.lisp and other parts of the comp.lang hierarchy. But that bit of the net kind of sank into the sewers of neglect. Is there a comparable one-stop-shop today? I am partially asking for selfish reasons, I know how to write good idiomatic C, Lisp, O'Caml, and Java code. But I learned C++ pre-template and STL, those rusty skills are not really applicable to today's C++. I have picked up languages like Scala in a vacuum and get by, but am I really doing it correctly? There are so many ways you can abuse a language, I am currently working against a codebase of Fortran written in C, and I recognize and loathe the "that guy" who wrote it. I don't want to be someone else's "that guy" if I can help it. Just because it works does not mean that one did not totally miss the boat on how it should have been done. Do you seek out this type of critique? If so how, where and why? What types of benefits do you derive from it? How about abuse and trolls?

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  • Using items in a list as arguments

    - by Travis Brown
    Suppose I have a function with the following type signature: g :: a -> a -> a -> b I also have a list of as—let's call it xs—that I know will contain at least three items. I'd like to apply g to the first three items of xs. I know I could define a combinator like the following: ($$$) :: (a -> a -> a -> b) -> [a] -> b f $$$ (x:y:z:_) = f x y z Then I could just use g $$$ xs. This makes $$$ a bit like uncurry, but for a function with three arguments of the same type and a list instead of a tuple. Is there a way to do this idiomatically using standard combinators? Or rather, what's the most idiomatic way to do this in Haskell? I thought trying pointfree on a non-infix version of $$$ might give me some idea of where to start, but the output was an abomination with 10 flips, a handful of heads and tails and aps, and 28 parentheses. (NB: I know this isn't a terribly Haskelly thing to do in the first place, but I've come across a couple of situations where it seems like a reasonable solution, especially when using Parsec. I'll certainly accept "don't ever do this in real code" if that's the best answer, but I'd prefer to see some clever trick involving the ((->) r) monad or whatever.)

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  • Python file iterator over a binary file with newer idiom.

    - by drewk
    In Python, for a binary file, I can write this: buf_size=1024*64 # this is an important size... with open(file, "rb") as f: while True: data=f.read(buf_size) if not data: break # deal with the data.... With a text file that I want to read line-by-line, I can write this: with open(file, "r") as file: for line in file: # deal with each line.... Which is shorthand for: with open(file, "r") as file: for line in iter(file.readline, ""): # deal with each line.... This idiom is documented in PEP 234 but I have failed to locate a similar idiom for binary files. I have tried this: >>> with open('dups.txt','rb') as f: ... for chunk in iter(f.read,''): ... i+=1 >>> i 1 # 30 MB file, i==1 means read in one go... I tried putting iter(f.read(buf_size),'') but that is a syntax error because of the parens after the callable in iter(). I know I could write a function, but is there way with the default idiom of for chunk in file: where I can use a buffer size versus a line oriented? Thanks for putting up with the Python newbie trying to write his first non-trivial and idiomatic Python script.

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  • F# ref-mutable vars vs object fields

    - by rwallace
    I'm writing a parser in F#, and it needs to be as fast as possible (I'm hoping to parse a 100 MB file in less than a minute). As normal, it uses mutable variables to store the next available character and the next available token (i.e. both the lexer and the parser proper use one unit of lookahead). My current partial implementation uses local variables for these. Since closure variables can't be mutable (anyone know the reason for this?) I've declared them as ref: let rec read file includepath = let c = ref ' ' let k = ref NONE let sb = new StringBuilder() use stream = File.OpenText file let readc() = c := stream.Read() |> char // etc I assume this has some overhead (not much, I know, but I'm trying for maximum speed here), and it's a little inelegant. The most obvious alternative would be to create a parser class object and have the mutable variables be fields in it. Does anyone know which is likely to be faster? Is there any consensus on which is considered better/more idiomatic style? Is there another option I'm missing?

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  • Accessing vars from another clojure namespace?

    - by erikcw
    In my main namespace, I have a top level var named "settings" which is initialized as an empty {}. My -main fn sets the contents of settings using def and conj based on some command line args (different database hosts for production/development, etc). I'm trying to access the contents of this map from another namespace to pull out some of the settings. When I try to compile with lein into an uberjar, I get a traceback saying "No such var: lb/settings". What am I missing? Is there a more idiomatic way to handle app wide settings such as these? Is it safe to use "def" inside of -main like I am, or should I be use an atom or ref to make this threadsafe? Thanks! (ns main (:use ...) (:gen-class)) (def settings {}) (defn -main [& args] (with-command-line-args... ;set devel? based on args (if (true? devel?) (def settings (conj settings {:mongodb {:host "127.0.0.1"} :memcached {:host "127.0.0.1"}})) (def settings (conj settings {:mongodb {:host "PRODUCTION_IP"} :memcached {:host "PRODUCTION_IP"}}))) ;file2.clj (ns some-other-namespace (:require [main :as lb] ...) ;configure MongoDB (congo/mongo! :db "dbname" :host (:host (mongodb lb/settings)))) ...

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  • jQuery way to replace just a text node with a mix of HTML and text

    - by hippietrail
    In my web browser userscript project I need to replace just one text node without affecting the other HTML elements under the same parent node as the text. And I need to replace it with more than one node: <div id="target"> some text<img src="/image.png"> </div> Needs to become: <div id="target"> <a href="#">mixed</a> text <a href="#">and</a> HTML<img src="/image.png"> </div> I know jQuery doesn't have a whole lot of support for text nodes. I know I could use direct DOM calls instead of jQuery. And I know I could just do something like $('#target').html(my new stuff + stuff I don't want to change). What I'd like to ask the experts here is, Is there a most idiomatic jQuery way to do this?

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  • Prevent coersion to a single type in unlist() or c(); passing arguments to wrapper functions

    - by Leo Alekseyev
    Is there a simple way to flatten a list while retaining the original types of list constituents?.. Is there a way to programmatically construct a heterogeneous list?.. For instance, I want to create a simple wrapper for functions like png(filename,width,height) that would take device name, file name, and a list of options. The naive approach would be something like my.wrapper <- function(dev,name,opts) { do.call(dev,c(filename=name,opts)) } or similar code with unlist(list(...)). This doesn't work because opts gets coerced to character, and the resulting call is e.g. png(filename,width="500",height="500"). If there's no straightforward way to create heterogeneous lists like that, is there a standard idiomatic way to splice arguments into functions without naming them explicitly (e.g. do.call(dev,list(filename=name,width=opts["width"]))? -- Edit -- Gavin Simpson answered both questions below in his discussion about constructing wrapper functions. Let me give a summary of the answer to the title question: It is possible to construct a heterogeneous list with c() provided the arguments to c() are lists. To wit: > foo <- c("a","b"); bar <- 1:3 > c(foo,bar) [1] "a" "b" "1" "2" "3" > c(list(foo),list(bar)) [[1]] [1] "a" "b" [[2]] [1] 1 2 3 > c(as.list(foo),as.list(bar)) ## this creates a flattened heterogeneous list [[1]] [1] "a" [[2]] [1] "b" [[3]] [1] 1 [[4]] [1] 2 [[5]] [1] 3

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  • Rails dealing with blank params at controller level

    - by stephenmurdoch
    I have a User model: class User < ActiveRecord::Base has_secure_password # validation lets users update accounts without entering password validates :password, presence: { on: :create }, allow_blank: { on: :update } validates :password_confirmation, presence: { if: :password_digest_changed? } end I also have a password_reset_controller: def update # this is emailed to the user by the create action - not shown @user=User.find_by_password_reset_token!(params[:id]) if @user.update_attributes(params[:user]) # user is signed in if password and confirmation pass validations sign_in @user redirect_to root_url, :notice => "Password has been reset." else flash.now[:error] = "Something went wrong, please try again." render :edit end end Can you see the problem here? A user can submit a blank a password/confirmation and rails will sign them in, because the User model allows blank on update. It's not a security concern, since an attacker would still need access to a user's email account before they could get anywhere near this action, but my problem is that a user submitting 6 blank chars would be signed in, and their password would not be changed for them, which could lead to confusion later on. So, I've come up with the following solution, and I'd like to check if there's a better way of doing it, before I push to production: def update @user=User.find_by_password_reset_token!(params[:id]) # if user submits blank password, add an error, and render edit action if params[:user][:password].blank? @user.errors.add(:password_digest, "can't be blank.") render :edit elsif @user.update_attributes(params[:user]) sign_in @user redirect_to root_url, :notice => "Password has been reset." else flash.now[:error] = "Something went wrong, please try again." render :edit end end Should I be checking for nil as well as blank? Are there any rails patterns or idiomatic ruby techniques for solving this? [Fwiw, I've got required: true on the html inputs, but want this handled server side too.]

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  • Another way to handle a common JQuery event handling pattern

    - by bradgonesurfing
    I have the following code for example $("a.foo").bind(function (e){ var t; if ( $(e.target).is("a") ){ t = $(e.target); }else{ t = $(e.target).parent("a"); } var data = t.attr("data-info"); }); In english. I might have a list of anchors within which there may be a number of spans. Each anchor is declared as <a class="foo" href="#" data-info="1"> <span> ... </span> <span> ... </span> </a> <a class="foo" href="#" data-info="2"> <span> ... </span> <span> ... </span> </a> ... ... I bind a handler to the click event of the anchor but the event object comes back with the anchor OR one of the spans depending on where I click. So to get my html5 "data-info" value into the callback I have to insert a bit of messy code. This is now appearing throughout my code to the point where I am guessing there might be an idiomatic JQuery way of handling this.

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  • Foreign-key-like merge in R

    - by skyl
    I'm merging a bunch of csv with 1 row per id/pk/seqn. > full = merge(demo, lab13am, by="seqn", all=TRUE) > full = merge(full, cdq, by="seqn", all=TRUE) > full = merge(full, mcq, by="seqn", all=TRUE) > full = merge(full, cfq, by="seqn", all=TRUE) > full = merge(full, diq, by="seqn", all=TRUE) > print(length(full$ridageyr)) [1] 9965 > print(summary(full$ridageyr)) Min. 1st Qu. Median Mean 3rd Qu. Max. 0.00 11.00 19.00 29.73 48.00 85.00 Everything is great. But, I have another file which has multiple rows per id like: "seqn","rxd030","rxd240b","nhcode","rxq250" 56,2,"","",NA,NA,"" 57,1,"ACETAMINOPHEN","01200",2 57,1,"BUDESONIDE","08800",1 58,1,"99999","",NA 57 has two rows. So, if I naively try to merge this file, I have a ton more rows and my data gets all skewed up. > full = merge(full, rxq, by="seqn", all=TRUE) > print(length(full$ridageyr)) [1] 15643 > print(summary(full$ridageyr)) Min. 1st Qu. Median Mean 3rd Qu. Max. 0.00 14.00 41.00 40.28 66.00 85.00 Is there a normal idiomatic way to deal with data like this? Suppose I want a way to make a simple model like MYSPECIAL_FACTOR <- somehow() glm(MYSPECIAL_FACTOR ~ full$ridageyr, family=binomial) where MYSPECIAL_FACTOR is, say, whether or not rxd240b == "ACETAMINOPHEN" for the observations which are unique by seqn. You can reproduce by running the first bit of this.

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