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  • Search for a pattern in a list of strings - Python

    - by Holtz
    I have a list of strings containing filenames such as, file_names = ['filei.txt','filej.txt','filek.txt','file2i.txt','file2j.txt','file2k.txt','file3i.txt','file3j.txt','file3k.txt'] I then remove the .txt extension using: extension = os.path.commonprefix([n[::-1] for n in file_names])[::-1] file_names_strip = [n[:-len(extension)] for n in file_names] And then return the last character of each string in the list file_names_strip: h = [n[-1:] for n in file_names_strip] Which gives h = ['i', 'j', 'k', 'i', 'j', 'k', 'i', 'j', 'k'] How can i test for a pattern of strings in h? So if i,j,k occur sequentially it would return True and False if not. I need to know this because not all file names are formatted like they are in file_names. So: test_ijk_pattern(h) = True no_pattern = ['1','2','3','1','2','3','1','2','3'] test_ijk_pattern(no_pattern) = False

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  • Python's JSON module doesn't use __get__?

    - by Matt
    When I serialize a list of objects with a custom __get__ method, __get__ is not called and the raw (unprocessed by custom __get__) value from __set__ is used. How does Python's json module iterate over an item? Note: if I iterate over the list before serializing, the correct value returned by __get__ is used.

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  • Is there a .NET equivalent of WebGoat

    - by PJB
    Looking at this question the OWASP WebGoat project looks like a great way to learn about web security. Although the principles will equally to .NET applications I would prefer to use .NET based application. Does anybody know of a suitable .NET alternative?

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  • Is there a pattern that allows a constructor to be called only from a specific factory and from nowh

    - by willem
    We have a class, say LegacyUserSettingsService. LegacyUserSettingsService implements an interface, IUserSettingsService. You can get an instance of the IUserSettingsService by calling our ApplicationServicesFactory. The factory uses Spring.NET to construct the concrete LegacyUserSettingsService. The trouble is that new developers sometimes do their own thing and construct new instances of the LegacyUserSettingsService directly (instead of going via the factory). Is there a way to protect the constructor of the concrete class so it can only be called from the factory? A well-known pattern perhaps? Note that the concrete class resides in a different assembly (separate from the Factory's assembly, so the internal keyword is not a solution). The factory assembly references the other assembly that contains the concrete class. Any ideas?

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  • What's the best way to unit test code that generates random output?

    - by Flynn1179
    Specifically, I've got a method picks n items from a list in such a way that a% of them meet one criterion, and b% meet a second, and so on. A simplified example would be to pick 5 items where 50% have a given property with the value 'true', and 50% 'false'; 50% of the time the method would return 2 true/3 false, and the other 50%, 3 true/2 false. Statistically speaking, this means that over 100 runs, I should get about 250 true/250 false, but because of the randomness, 240/260 is entirely possible. What's the best way to unit test this? I'm assuming that even though technically 300/200 is possible, it should probably fail the test if this happens. Is there a generally accepted tolerance for cases like this, and if so, how do you determine what that is?

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  • Efficient storage/retrieval method for replayable comet style applications (Google Wave, Etherpad)

    - by Gareth Simpson
    I am considering a web application that would have the same kind of multi user, automatic saving, infinite undo / replay capabilities that you see in Google Wave and Etherpad (albeit on a drastically smaller scale and userbase). Before I go away and reinvent the wheel, is this something that has already been addressed as either a piece of technology or library, or even just a design pattern. I know this isn't necessarily the best Stack Overflow question as there is probably not a "right" answer, but my Google-fu has failed me and I'd just like a reading list! Ordinarily I would be developing under python/django but this is not a firm requirement just a preference :)

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  • Premature optimization is the root of all evil, but can it ever be too late?

    - by polygenelubricants
    "We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil" So what is that 3% like? Can the avoidance of premature optimization ever be taken too extreme that it does more harm than good? Even if it's rare, has there been a case of a real measurable software engineering disaster due to complete negligence to optimize early in the process? Bonus question: is software engineering pretty much the only field that has such a counter intuitive principle regarding doing something earlier rather than later before things potentially become too big a problem to fix? Personal question: how do you justify something as premature optimization and not just a case of you being lazy/ignorant/dumb?

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  • paged list with checkboxes, keep the checkbox value browsing through the paging?

    - by Dejan.S
    Hi. I got a list of customers I thought I would list in a gridview or a repeater with customer html, it gone have paging. I'm gone have a checkbox for each customer in the list. Do you guys have any suggestions on how I should do to keep the checkbox value when I go to page 2-3-4 ect in the paging. I'm thinking a session to store the id of the checked customers. After I'm done setting the values they go to the database. Do you got any other ideas then the session I'm thinking of? thanks guys

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  • JSP application scope objects in Java library

    - by FrontierPsycho
    I am working on a preexisting web application built with JSP, which uses an external Java library. I want to make some JavaBeans that were instantiated with jsp:useBean tags available to the Java code. What would be a good practice to do that? I suppose I can pass the objects in question to every function call that requires them, but I'd like to avoid that.

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  • Conditional column values in NSTableView?

    - by velocityb0y
    I have an NSTableView that binds via an NSArrayController to an NSMutableArray. What's in the array are derived classes; the first few columns of the table are bound to properties that exist on the base class. That all works fine. Where I'm running into problem is a column that should only be populated if the row maps to one specific subclass. The property that column is meant to display only exists in that subclass, since it makes no sense in terms of the base class. The user will know, from the first two columns, why the third column's cell is populated/editable or not. The binding on the third column's value is on arrangedObjects, with a model path of something like "foo.name" where foo is the property on the subclass. However, this doesn't work, as the other subclasses in the hierarchy are not key-value compliant for foo. It seems like my only choice is to have foo be a property on the base class so everybody responds to it, but this clutters up the interfaces of the model objects. Has anyone come up with a clean design for this situation? It can't be uncommon (I'm a relative newcomer to Cocoa and I'm just learning the ins and outs of bindings.)

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  • Standard Workflow when working with JPA

    - by jschoen
    I am currently trying to wrap my head around working with JPA. I can't help but feel like I am missing something or doing it the wrong way. It just seems forced so far. What I think I know so far is that their are couple of ways to work with JPA and tools to support this. You can do everything in Java using annotations, and let JPA (whatever implementation you decide to use) create your schema and update it when changes are made. You can use a tool to reverse engineer you database and generate the entity classes for you. When the schema is updated you have to regenerate these classes, or manually update them. There seems to be drawbacks to both, and benefits to both (as with all things). My question is in an ideal situation what is the standard workflow with JPA? Most schemas will require updates during the maintenance phase and especially during the development phase, so how is this handled?

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  • Writing a custom iterator -- what to do if you're at the end of the array?

    - by Goose Bumper
    I'm writing a custom iterator for a Matrix class, and I want to implement the increment method, which gets called when the iterator is incremented: void MatrixIterator::increment() { // go to the next element } Suppose the iterator has been incremented too many times and now points to past the end of the matrix (i.e. past the one-past-the-end point). What is the best practice for this situation? Should I catch this with an assert, or should I just say it's the user's responsibility to keep track of where the iterator is pointing and it's none of my business?

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  • Converting a constantly changing scalar value to a changing interval or frequency

    - by eco_bach
    Although I'm coding in Objective C, this is more of a general programming question. What is the best way to convert a constantly changing scalar value to a changing interval or frequency? Right now every time the scalar value changes I am destroying the NSInterval ie [self.myTimer invalidate]; self.myTimer = nil; and creating a new one, but this seems like a VERY expensive way to achieve my goal, since the changing scalar value in my case represents the horizontal velocity of a swipe. For a rough analogy, think of the speed of a swipe being reflected in a visual metronome, the faster you swipe, the higher(shorter interval) the frequency of the metronome.

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  • distributing R package with optional S4 syntax sugar

    - by mariotomo
    I've written a small package for logging, I'm distributing it through r-forge, recently I received some very interesting feedback on how to make it easier to use, but this functionality is based on stuff (setRefClass) that was added to R in 2.12. I'd like to keep distributing the package also for R-2.9, so I'm looking for a way to include or exclude the S4 syntactical sugar automatically, and include it when the library is loaded on a R = 2.12 system. one other option I see, that is to write a small S4 package that needs 2.12, imports the simpler logging package and exports the syntactically sugared interface... I don't like it too much, as I'd need to choose a different name for the S4 package.

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  • Tips for documenting a web application?

    - by Pandiya Chendur
    I know that I can take my asp.net application and get it reversed to a UML document, but that doesn't tell the whole story of things like who can use what, what it calls in the way of stored procedures, what pages call what pages etc. etc. Does anyone know of an article where someone has a comprehensive way to document a web application/site? Or shall I just make up my own way?

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  • What XSS/CSRF attacks (if any) to be aware of when allowing video embeds?

    - by fireeyedboy
    I've been assigned a project for a website where users will be allowed to upload video's (using a YouTube API) but more importantly (for me) they will also be allowed to submit video embed codes (from numerous video sites, YouTube, Vimeo, etc. etc.). Having no experience with allowing users to embed video: How can I best protect against cross site scripting and/or cross site request forgery attacks specifically for video embedding? What are some of the common pitfalls to watch for? At a minumum I would think to strip all tags except <object> and <embed>. But I have a feeling this will not be enough, will it? If it is of importance, the environment will be: PHP/Zend Framework MySQL Bonuspoints: Is there a common minimum golden rule/code template for video embed codes that are valid across all video sites that I could use to filter the input?

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  • How to check for mip-map availability in OpenGL?

    - by Xavier Ho
    Recently I bumped into a problem where my OpenGL program would not render textures correctly on a 2-year-old Lenovo laptop with an nVidia Quadro 140 card. It runs OpenGL 2.1.2, and GLSL 1.20, but when I turned on mip-mapping, the whole screen is black, with no warnings or errors. This is my texture filter code: glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE); After 40 minutes of fiddling around, I found out mip-mapping was the problem. Turning it off fixed it: // glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE); I get a lot of aliasing, but at least the program is visible and runs fine. Finally, two questions: What's the best or standard way to check if mip-mapping is available on a machine, aside from checking OpenGL versions? If mip-mapping is not available, what's the best work-around to avoid aliasing?

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  • A good approach to db planing for reporting service

    - by Itay Moav
    The scenario: Big system (~200 tables). 60,000 users. Complex reports that will require me to do multiple queries for each report and even those will be complex queries with inner queries all over the place + some processing in PHP. I have seen an approach, which I am not sure about: Having one centralized, de-normalized, table that registers any activity in the system which is reportable. This table will hold mostly foreign keys, so she should be fairly compact and fast. So, for example (My system is a virtual learning management system), A user enrolls to course, the table stores the user id, date, course id, organization id, activity type (enrollment). Of course I also store this data in a normalized DB, which the actual application uses. Pros I see: easy, maintainable queries and code to process data and fast retrieval. Cons: there is a danger of the de-normalized table to be out of sync with the real DB. Is this approach worth considering, or (preferably from experience) is total $#%#%t?

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  • What is the best way to identify which form has been submitted?

    - by Rupert
    Currently, when I design my forms, I like to keep the name of the submit button equal to the id of the form. Then, in my php, I just do if(isset($_POST['submitName'])) in order to check if a form has been submitted and which form has been submitted. Firstly, are there any security problems or design flaws with this method? One problem I have encountered is when I wish to overlay my forms with javascript in order to provide faster validation to the user. For example, whilst I obviously need to retain server side validation, it is more convenient for the user if an error message is displayed inline, upon blurring an input. Additionally, it would be good to provide entire form validation, upon clicking the submit button. Therefore, when the user clicks on the form's submit button, I am stopping the default action, doing my validation, and then attempting to renable the traditional submit functionality, if the validation passes. In order to do this, I am using the form.submit() method but, unfortunately, this doesn't send the submit button variable (as it should be as form.submit() can be called without any button being clicked). This means my PHP script fails to detect that the form has been submitted. What is the correct way to work around this? It seems like the standard solution is to add a hidden field into the form, upon passing validation, which has the name of form's id. Then when form.submit() is called, this is passed along in place of the submit button. However, this solution seems very ungraceful to me and so I am wondering whether I should: a) Use an alternative method to detect which form has been submitted which doesn't rely rely on passing the submit button. If so what alternative is there? Obviously, just having an extra hidden field from the start isn't any better. b) Use an alternative Javascript solution which allows me to retain my non-Javascript design. For example, is there an alternative to form.submit() which allows me to pass in extra data? c) Suck it up and just insert a hidden field using Javascript.

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  • html clickable layout area. best practice

    - by Andrew Florko
    I am bad in html layout but I have to produce it :) I want to make big button on a page that is implemented as div with children tags (maybe - a bad idea). I can handle click event on boundary-div with javascript but it requires javascript enabled. I can wrap boundary-div with "anchor" tag but is doesn't work in IE Please, suggest me the best way to implement this. <a href="..."> <table> <td> ... </td> <td> ... <table> ... </table> </td> </table> </a>

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  • Handling Dialogs in WPF with MVVM

    - by Ray Booysen
    In the MVVM pattern for WPF, handling dialogs is one of the more complex operations. As your view model does not know anything about the view, dialog communication can be interesting. I can expose an ICommand that when the view invokes it, a dialog can appear. Does anyone know of a good way to handle results from dialogs? I am speaking about windows dialogs such as MessageBox. One of the ways we did this was have an event on the viewmodel that the view would subscribe to when a dialog was required. public event EventHandler<MyDeleteArgs> RequiresDeleteDialog; This is OK, but it means that the view requires code which is something I would like to stay away from.

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