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  • UppercuT &ndash; Custom Extensions Now With PowerShell and Ruby

    - by Robz / Fervent Coder
    Arguably, one of the most powerful features of UppercuT (UC) is the ability to extend any step of the build process with a pre, post, or replace hook. This customization is done in a separate location from the build so you can upgrade without wondering if you broke the build. There is a hook before each step of the build has run. There is a hook after. And back to power again, there is a replacement hook. If you don’t like what the step is doing and/or you want to replace it’s entire functionality, you just drop a custom replacement extension and UppercuT will perform the custom step instead. Up until recently all custom hooks had to be written in NAnt. Now they are a little sweeter because you no longer need to use NAnt to extend UC if you don’t want to. You can use PowerShell. Or Ruby.   Let that sink in for a moment. You don’t have to even need to interact with NAnt at all now. Extension Points On the wiki, all of the extension points are shown. The basic idea is that you would put whatever customization you are doing in a separate folder named build.custom. Each step Let’s take a look at all we can customize: The start point is default.build. It calls build.custom/default.pre.build if it exists, then it runs build/default.build (normal tasks) OR build.custom/default.replace.build if it exists, and finally build.custom/default.post.build if it exists. Every step below runs with the same extension points but changes on the file name it is looking for. NOTE: If you include default.replace.build, nothing else will run because everything is called from default.build.    * policyChecks.step    * versionBuilder.step NOTE: If you include build.custom/versionBuilder.replace.step, the items below will not run.      - svn.step, tfs.step, or git.step (the custom tasks for these need to go in build.custom/versioners)    * generateBuildInfo.step    * compile.step    * environmentBuilder.step    * analyze.step NOTE: If you include build.custom/analyze.replace.step, the items below will not run.      - test.step (the custom tasks for this need to go in build.custom/analyzers) NOTE: If you include build.custom/analyzers/test.replace.step, the items below will not run.        + mbunit2.step, gallio.step, or nunit.step (the custom tasks for these need to go in build.custom/analyzers)      - ncover.step (the custom tasks for this need to go in build.custom/analyzers)      - ndepend.step (the custom tasks for this need to go in build.custom/analyzers)      - moma.step (the custom tasks for this need to go in build.custom/analyzers)    * package.step NOTE: If you include build.custom/package.replace.step, the items below will not run.      - deploymentBuilder.step Customize UppercuT Builds With PowerShell UppercuT can now be extended with PowerShell (PS). To customize any extension point with PS, just add .ps1 to the end of the file name and write your custom tasks in PowerShell. If you are not signing your scripts you will need to change a setting in the UppercuT.config file. This does impose a security risk, because this allows PS to now run any PS script. This setting stays that way on ANY machine that runs the build until manually changed by someone. I’m not responsible if you mess up your machine or anyone else’s by doing this. You’ve been warned. Now that you are fully aware of any security holes you may open and are okay with that, let’s move on. Let’s create a file called default.replace.build.ps1 in the build.custom folder. Open that file in notepad and let’s add this to it: write-host "hello - I'm a custom task written in Powershell!" Now, let’s run build.bat. You could get some PSake action going here. I won’t dive into that in this post though. Customize UppercuT Builds With Ruby If you want to customize any extension point with Ruby, just add .rb to the end of the file name and write your custom tasks in Ruby.  Let’s write a custom ruby task for UC. If you were thinking it would be the same as the one we just wrote for PS, you’d be right! In the build.custom folder, lets create a file called default.replace.build.rb. Open that file in notepad and let’s put this in there: puts "I'm a custom ruby task!" Now, let’s run build.bat again. That’s chunky bacon. UppercuT and Albacore.NET Just for fun, I wanted to see if I could replace the compile.step with a Rake task. Not just any rake task, Albacore’s msbuild task. Albacore is a suite of rake tasks brought about by Derick Bailey to make building .NET with Rake easier. It has quite a bit of support with developers that are using Rake to build code. In my build.custom folder, I drop a compile.replace.step.rb. I also put in a separate file that will contain my Albacore rake task and I call that compile.rb. What are the contents of compile.replace.step.rb? rake = 'rake' arguments= '-f ' + Dir.pwd + '/../build.custom/compile.rb' #puts "Calling #{rake} " + arguments system("#{rake} " + arguments) Since the custom extensions call ruby, we have to shell back out and call rake. That’s what we are doing here. We also realize that ruby is called from the build folder, so we need to back out and dive into the build.custom folder to find the file that is technically next to us. What are the contents of compile.rb? require 'rubygems' require 'fileutils' require 'albacore' task :default => [:compile] puts "Using Ruby to compile UppercuT with Albacore Tasks" desc 'Compile the source' msbuild :compile do |msb| msb.properties = { :configuration => :Release, :outputpath => '../../build_output/UppercuT' } msb.targets [:clean, :build] msb.verbosity = "quiet" msb.path_to_command = 'c:/Windows/Microsoft.NET/Framework/v3.5/MSBuild.exe' msb.solution = '../uppercut.sln' end We are using the msbuild task here. We change the output path to the build_output/UppercuT folder. The output path has “../../” because this is based on every project. We could grab the current directory and then point the task specifically to a folder if we have projects that are at different levels. We want the verbosity to be quiet so we set that as well. So what kind of output do you get for this? Let’s run build.bat custom_tasks_replace:      [echo] Running custom tasks instead of normal tasks if C:\code\uppercut\build\..\build.custom\compile.replace.step exists.      [exec] (in C:/code/uppercut/build)      [exec] Using Ruby to compile UppercuT with Albacore Tasks      [exec] Microsoft (R) Build Engine Version 3.5.30729.4926      [exec] [Microsoft .NET Framework, Version 2.0.50727.4927]      [exec] Copyright (C) Microsoft Corporation 2007. All rights reserved. If you think this is awesome, you’d be right!   With this knowledge you shall build.

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  • Python creating a dictionary and swapping these into another file

    - by satsurae
    Hi all, I have two tab delimited .csv file. From one.csv I have created a dictionary which looks like: 'EB2430': ' "\t"idnD "\t"yjgV "\t"b4267 "\n', 'EB3128': ' "\t"yagE "\t\t"b0268 "\n', 'EB3945': ' "\t"maeB "\t"ypfF "\t"b2463 "\n', 'EB3944': ' "\t"eutS "\t"ypfE "\t"b2462 "\n', I would like to insert the value of the dictionary into the second.csv file which looks like: "EB2430" 36.81 364 222 4 72 430 101 461 1.00E-063 237 "EB3128" 26.04 169 108 6 42 206 17 172 6.00E-006 45.8 "EB3945" 20.6 233 162 6 106 333 33 247 6.00E-005 42.4 "EB3944" 19.07 367 284 6 1 355 1 366 2.00E-023 103 With a resultant output tab delimited: 'EB2430' idnD yjgV b4267 36.81 364 222 4 72 430 101 461 1.00E-063 237 'EB3128' yagE b0268 26.04 169 108 6 42 206 17 172 6.00E-006 45.8 'EB3945' maeB ypfF b2463 20.6 233 162 6 106 333 33 247 6.00E-005 42.4 'EB3944' eutS ypfE b2462 19.07 367 284 6 1 355 1 366 2.00E-023 103 Here is my code for creating the dictionary: f = open ("one.csv", "r") g = open ("second.csv", "r") eb = [] desc = [] di = {} for line in f: for row in f: eb.append(row[1:7]) desc.append(row[7:]) di = dict(zip(eb,desc)) Sorry for it being so long-winded!! I've not been programming for long. Cheers! Sat

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  • Creating a dictionary with list of lists in Python

    - by ghbhatt
    I have a huge file (with around 200k inputs). The inputs are in the form: A B C D B E F C A B D D I am reading this file and storing it in a list as follows: text = f.read().split('\n') This splits the file whenever it sees a new line. Hence text is like follows: [[A B C D] [B E F] [C A B D] [D]] I have to now store these values in a dictionary where the key values are the first element from each list. i.e the keys will be A, B, C, D. I am finding it difficult to enter the values as the remaining elements of the list. i.e the dictionary should look like: {A: B C D; B: E F; C: A B D; D: 0} I have done the following: inlinkDict = {} for doc in text: adoc= doc.split(' ') docid = adoc[0] inlinkDict[docid] = inlinkDict.get(docid,0) + {I do not understand what to put in here} Please help as to how should i add the values to my dictionary. It should be 0 if there are no elements in the list except for the one which will be the key value. Like in example for 0.

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  • what's a good way to implement something that looks like Dictionary<string, string, Dictionary<strin

    - by jcollum
    I've got a data structure that is Key, Value, OtherValues(key, Value). So the OtherValues are attached to the first Key and aren't always there. I can do this as Dictionary<Key, ValueAndListOfOptionalValues> where ValueAndListOfOptionalValues is a class with a string and a Dictionary<string, string>. I'm wondering if that's really the best way to do it? Sometimes I think that I'm missing some important classes in the Generics namespace, maybe there are better classes out there that I'm not aware of.

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  • How to Create Custom Personalized Maps in Google Maps [Video]

    - by Asian Angel
    Though the custom maps feature has been out for a bit, you may have forgotten about it or it may all be new for you. Either way this wonderful video shows you how to create your own custom maps and enjoy an awesome feature of this popular Google service. ‘My Maps’ is mentioned in the video above, but is now referred to as ‘My Places’ in Google Maps (as seen below). There is also a nice interactive tutorial available. How to Use an Xbox 360 Controller On Your Windows PC Download the Official How-To Geek Trivia App for Windows 8 How to Banish Duplicate Photos with VisiPic

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  • Dictionary is returning false on ContainsKey after item is added

    - by Karel Frajtak
    I have a dictionary declared as follows IDictionary<string, object> _objectIds = new Dictionary<string, object>(); I was experiencing some problems with it and it discovered that the instance returned false as a result of ContainsKey method and from the watch window I was sure that the item was there. So I created helper method private bool IdsContainsKey(string key) { lock (syncObject) { lock (_objectIds) { if (_objectIds.ContainsKey(key)) return true; // A if (_objectIds.ContainsKey(key)) return true; // B return _objectIds.ContainsKey(key); // C } } } During my debugging session I run into situation when the method exited in place B and sometimes I made to C returning true. Can anybody help me? Thanks.

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  • emacs & icicles: auto-completion from a dictionary?

    - by Mica
    I just installed icicles with emacs, and so far I am liking it a lot. I'm not entirely sure if this is possible, but I would like to implement (or use, if it already exists) a feature in icicles that would auto-complete words from an English dictionary. So, if I'm writing something and need a word that rhymes with floor, I can type in *or, or even better, for alliteration, type in flo* and have it return all the words from the dictionary that start with flo Questions: Does something like this exist? If it does not exist, what would be the best way to go about this? Should I somehow hook into aspell? Or just index a long file of words?

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  • Retrieving search results from Google, Google Images, Wikipedia, Flickr, Dictionary.com

    - by Arjun Vasudevan
    I've an ASP.NET page with a textbox and a option from user of the following choices: Wikipedia, Google, Dictionary.com, Flickr, Google images. The user enters a word(s) in the textbox and selects a choice among the following. Depending on the choice select by the user I wish to return the following. Wikipedia: Return the content and link to the page corresponding to the topic about the word. Google: Return the top 10 results of google search for this word. Flickr: Return a few images atmost 10 images from flickr search GoogleImage: Return a few images from google image search. Dictionary: Return the meaning of the word. How can I do that? Which tool box control can I use for holding the results coming from these sites?

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  • Django dictionary in templates: Grab key from another objects attribute

    - by Jordan Messina
    I have a dictionary called number_devices I'm passing to a template, the dictionary keys are the ids of a list of objects I'm also passing to the template (called implementations). I'm iterating over the list of objects and then trying to use the object.id to get a value out of the dict like so: {% for implementation in implementations %} {{ number_devices.implementation.id }} {% endfor %} Unfortunately number_devices.implementation is evaluated first, then the result.id is evaluated obviously returning and displaying nothing. I can't use parentheses like: {{ number_devices.(implementation.id) }} because I get a parse error. How do I get around this annoyance in Django templates? Thanks for any help!

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  • Wherewith replace Dictionary.Where(p => p.Key is T)

    - by abatishchev
    I have a System.Collections.Generic.Dictionary<System.Web.UI.Control, object> where all keys can be either type of System.Web.UI.WebControls.HyperLink or type of System.Web.UI.WebControls.Label. I want to change Text property of each control. Because HyperLink doesn't implement (why??) ITextControl, I need to cast Label or HyperLink explicitly: Dictionary<Control,object> dic = .. dic .Where(p => p.Key is HyperLink) .ForEach(c => ((HyperLink)c).Text = "something") dic .Where(p => p.Key is Label) .ForEach(c => ((Label)c).Text = "something") Are there ways to workaround such approach?

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  • Django: Converting an entire Model into a single dictionary

    - by LarrikJ
    Is there a good way in Django to convert an entire model to a dictionary? I mean, like this: class DictModel(models.Model): key = models.CharField(20) value = models.CharField(200) DictModel.objects.all().to_dict() ... with the result being a dictionary with the key/value pairs made up of records in the Model? Has anyone else seen this as being useful for them? Thanks. Update I just wanted to add is that my ultimate goal is to be able to do a simple variable lookup inside a Template. Something like: {{ DictModel.exampleKey }} With a result of DictModel.objects.get(key__exact=exampleKey).value Overall, though, you guys have really surprised me with how helpful allof your responses are, and how different the ways to approach it can be. Thanks a lot.

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  • Obtaining Index value of dictionary

    - by Maudise
    I have a piece of code which looks at the following public Test As Dictionary(Of String, String()) Which is brought in tester = New Dictionary(Of String, String()) tester.add("Key_EN", {"Option 1_EN", "Option 2_EN", "Option 3_EN"}) tester.add("Key_FR", {"Option 1_FR", "Option 2_FR", "Option 3_FR"}) tester.add("Key_DE", {"Option 1_DE", "Option 2_DE", "Option 3_DE"}) There's then a combo box which looks at the following dim Language as string Language = "_EN" ' note this is done by a drop down combo box to select _EN or _FR etc. cboTestBox.items.AddRange(tester("Key" & Language)) What I need to be able to do is to see what index position the answer is in and convert it back to the Key_EN. So, for example _DE is selected, then the options of "Option 1_DE", "Option 2_DE", "Option 3_DE" would be displayed. If they chose Option 3_DE then I need to be able to convert this to Option 3_EN. Many thanks Maudise

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  • Developing a custom-validation in asp.net for specific control and criteria

    - by Gaurav
    Hello There is another relevant question asked Validation Check in asp.net In the same scenario we need a custom validator control which will alert user for any wrong entry. This will work like this : Developer will pass the control-name, input-value and format-required For instance like for textbox it can be: txtName,txtName.Text, allow-alphabets-only The accordingly format if the user input is invalid he/she will be got prompt. Please suggest the right way to do the smae. Thanks in advance.

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  • Python dictionary key missing

    - by Greg K
    I thought I'd put together a quick script to consolidate the CSS rules I have distributed across multiple CSS files, then I can minify it. I'm new to Python but figured this would be a good exercise to try a new language. My main loop isn't parsing the CSS as I thought it would. I populate a list with selectors parsed from the CSS files to return the CSS rules in order. Later in the script, the list contains an element that is not found in the dictionary. for line in self.file.readlines(): if self.hasSelector(line): selector = self.getSelector(line) if selector not in self.order: self.order.append(selector) elif selector and self.hasProperty(line): # rules.setdefault(selector,[]).append(self.getProperty(line)) property = self.getProperty(line) properties = [] if selector not in rules else rules[selector] if property not in properties: properties.append(property) rules[selector] = properties # print "%s :: %s" % (selector, "".join(rules[selector])) return rules Error encountered: $ css-combine combined.css test1.css test2.css Traceback (most recent call last): File "css-combine", line 108, in <module> c.run(outfile, stylesheets) File "css-combine", line 64, in run [(selector, rules[selector]) for selector in parser.order], KeyError: 'p' Swap the inputs: $ css-combine combined.css test2.css test1.css Traceback (most recent call last): File "css-combine", line 108, in <module> c.run(outfile, stylesheets) File "css-combine", line 64, in run [(selector, rules[selector]) for selector in parser.order], KeyError: '#header_.title' I've done some quirky things in the code like sub spaces for underscores in dictionary key names in case it was an issue - maybe this is a benign precaution? Depending on the order of the inputs, a different key cannot be found in the dictionary. The script: #!/usr/bin/env python import optparse import re class CssParser: def __init__(self): self.file = False self.order = [] # store rules assignment order def parse(self, rules = {}): if self.file == False: raise IOError("No file to parse") selector = False for line in self.file.readlines(): if self.hasSelector(line): selector = self.getSelector(line) if selector not in self.order: self.order.append(selector) elif selector and self.hasProperty(line): # rules.setdefault(selector,[]).append(self.getProperty(line)) property = self.getProperty(line) properties = [] if selector not in rules else rules[selector] if property not in properties: properties.append(property) rules[selector] = properties # print "%s :: %s" % (selector, "".join(rules[selector])) return rules def hasSelector(self, line): return True if re.search("^([#a-z,\.:\s]+){", line) else False def getSelector(self, line): s = re.search("^([#a-z,:\.\s]+){", line).group(1) return "_".join(s.strip().split()) def hasProperty(self, line): return True if re.search("^\s?[a-z-]+:[^;]+;", line) else False def getProperty(self, line): return re.search("([a-z-]+:[^;]+;)", line).group(1) class Consolidator: """Class to consolidate CSS rule attributes""" def run(self, outfile, files): parser = CssParser() rules = {} for file in files: try: parser.file = open(file) rules = parser.parse(rules) except IOError: print "Cannot read file: " + file finally: parser.file.close() self.serialize( [(selector, rules[selector]) for selector in parser.order], outfile ) def serialize(self, rules, outfile): try: f = open(outfile, "w") for rule in rules: f.write( "%s {\n\t%s\n}\n\n" % ( " ".join(rule[0].split("_")), "\n\t".join(rule[1]) ) ) except IOError: print "Cannot write output to: " + outfile finally: f.close() def init(): op = optparse.OptionParser( usage="Usage: %prog [options] <output file> <stylesheet1> " + "<stylesheet2> ... <stylesheetN>", description="Combine CSS rules spread across multiple " + "stylesheets into a single file" ) opts, args = op.parse_args() if len(args) < 3: if len(args) == 1: print "Error: No input files specified.\n" elif len(args) == 2: print "Error: One input file specified, nothing to combine.\n" op.print_help(); exit(-1) return [opts, args] if __name__ == '__main__': opts, args = init() outfile, stylesheets = [args[0], args[1:]] c = Consolidator() c.run(outfile, stylesheets) Test CSS file 1: body { background-color: #e7e7e7; } p { margin: 1em 0em; } File 2: body { font-size: 16px; } #header .title { font-family: Tahoma, Geneva, sans-serif; font-size: 1.9em; } #header .title a, #header .title a:hover { color: #f5f5f5; border-bottom: none; text-shadow: 2px 2px 3px rgba(0, 0, 0, 1); } Thanks in advance.

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  • C#/.NET Little Wonders: The ConcurrentDictionary

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In this series of posts, we will discuss how the concurrent collections have been developed to help alleviate these multi-threading concerns.  Last week’s post began with a general introduction and discussed the ConcurrentStack<T> and ConcurrentQueue<T>.  Today's post discusses the ConcurrentDictionary<T> (originally I had intended to discuss ConcurrentBag this week as well, but ConcurrentDictionary had enough information to create a very full post on its own!).  Finally next week, we shall close with a discussion of the ConcurrentBag<T> and BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. Recap As you'll recall from the previous post, the original collections were object-based containers that accomplished synchronization through a Synchronized member.  While these were convenient because you didn't have to worry about writing your own synchronization logic, they were a bit too finely grained and if you needed to perform multiple operations under one lock, the automatic synchronization didn't buy much. With the advent of .NET 2.0, the original collections were succeeded by the generic collections which are fully type-safe, but eschew automatic synchronization.  This cuts both ways in that you have a lot more control as a developer over when and how fine-grained you want to synchronize, but on the other hand if you just want simple synchronization it creates more work. With .NET 4.0, we get the best of both worlds in generic collections.  A new breed of collections was born called the concurrent collections in the System.Collections.Concurrent namespace.  These amazing collections are fine-tuned to have best overall performance for situations requiring concurrent access.  They are not meant to replace the generic collections, but to simply be an alternative to creating your own locking mechanisms. Among those concurrent collections were the ConcurrentStack<T> and ConcurrentQueue<T> which provide classic LIFO and FIFO collections with a concurrent twist.  As we saw, some of the traditional methods that required calls to be made in a certain order (like checking for not IsEmpty before calling Pop()) were replaced in favor of an umbrella operation that combined both under one lock (like TryPop()). Now, let's take a look at the next in our series of concurrent collections!For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. ConcurrentDictionary – the fully thread-safe dictionary The ConcurrentDictionary<TKey,TValue> is the thread-safe counterpart to the generic Dictionary<TKey, TValue> collection.  Obviously, both are designed for quick – O(1) – lookups of data based on a key.  If you think of algorithms where you need lightning fast lookups of data and don’t care whether the data is maintained in any particular ordering or not, the unsorted dictionaries are generally the best way to go. Note: as a side note, there are sorted implementations of IDictionary, namely SortedDictionary and SortedList which are stored as an ordered tree and a ordered list respectively.  While these are not as fast as the non-sorted dictionaries – they are O(log2 n) – they are a great combination of both speed and ordering -- and still greatly outperform a linear search. Now, once again keep in mind that if all you need to do is load a collection once and then allow multi-threaded reading you do not need any locking.  Examples of this tend to be situations where you load a lookup or translation table once at program start, then keep it in memory for read-only reference.  In such cases locking is completely non-productive. However, most of the time when we need a concurrent dictionary we are interleaving both reads and updates.  This is where the ConcurrentDictionary really shines!  It achieves its thread-safety with no common lock to improve efficiency.  It actually uses a series of locks to provide concurrent updates, and has lockless reads!  This means that the ConcurrentDictionary gets even more efficient the higher the ratio of reads-to-writes you have. ConcurrentDictionary and Dictionary differences For the most part, the ConcurrentDictionary<TKey,TValue> behaves like it’s Dictionary<TKey,TValue> counterpart with a few differences.  Some notable examples of which are: Add() does not exist in the concurrent dictionary. This means you must use TryAdd(), AddOrUpdate(), or GetOrAdd().  It also means that you can’t use a collection initializer with the concurrent dictionary. TryAdd() replaced Add() to attempt atomic, safe adds. Because Add() only succeeds if the item doesn’t already exist, we need an atomic operation to check if the item exists, and if not add it while still under an atomic lock. TryUpdate() was added to attempt atomic, safe updates. If we want to update an item, we must make sure it exists first and that the original value is what we expected it to be.  If all these are true, we can update the item under one atomic step. TryRemove() was added to attempt atomic, safe removes. To safely attempt to remove a value we need to see if the key exists first, this checks for existence and removes under an atomic lock. AddOrUpdate() was added to attempt an thread-safe “upsert”. There are many times where you want to insert into a dictionary if the key doesn’t exist, or update the value if it does.  This allows you to make a thread-safe add-or-update. GetOrAdd() was added to attempt an thread-safe query/insert. Sometimes, you want to query for whether an item exists in the cache, and if it doesn’t insert a starting value for it.  This allows you to get the value if it exists and insert if not. Count, Keys, Values properties take a snapshot of the dictionary. Accessing these properties may interfere with add and update performance and should be used with caution. ToArray() returns a static snapshot of the dictionary. That is, the dictionary is locked, and then copied to an array as a O(n) operation.  GetEnumerator() is thread-safe and efficient, but allows dirty reads. Because reads require no locking, you can safely iterate over the contents of the dictionary.  The only downside is that, depending on timing, you may get dirty reads. Dirty reads during iteration The last point on GetEnumerator() bears some explanation.  Picture a scenario in which you call GetEnumerator() (or iterate using a foreach, etc.) and then, during that iteration the dictionary gets updated.  This may not sound like a big deal, but it can lead to inconsistent results if used incorrectly.  The problem is that items you already iterated over that are updated a split second after don’t show the update, but items that you iterate over that were updated a split second before do show the update.  Thus you may get a combination of items that are “stale” because you iterated before the update, and “fresh” because they were updated after GetEnumerator() but before the iteration reached them. Let’s illustrate with an example, let’s say you load up a concurrent dictionary like this: 1: // load up a dictionary. 2: var dictionary = new ConcurrentDictionary<string, int>(); 3:  4: dictionary["A"] = 1; 5: dictionary["B"] = 2; 6: dictionary["C"] = 3; 7: dictionary["D"] = 4; 8: dictionary["E"] = 5; 9: dictionary["F"] = 6; Then you have one task (using the wonderful TPL!) to iterate using dirty reads: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); And one task to attempt updates in a separate thread (probably): 1: // attempt updates in a separate thread 2: var updateTask = new Task(() => 3: { 4: // iterates, and updates the value by one 5: foreach (var pair in dictionary) 6: { 7: dictionary[pair.Key] = pair.Value + 1; 8: } 9: }); Now that we’ve done this, we can fire up both tasks and wait for them to complete: 1: // start both tasks 2: updateTask.Start(); 3: iterationTask.Start(); 4:  5: // wait for both to complete. 6: Task.WaitAll(updateTask, iterationTask); Now, if I you didn’t know about the dirty reads, you may have expected to see the iteration before the updates (such as A:1, B:2, C:3, D:4, E:5, F:6).  However, because the reads are dirty, we will quite possibly get a combination of some updated, some original.  My own run netted this result: 1: F:6 2: E:6 3: D:5 4: C:4 5: B:3 6: A:2 Note that, of course, iteration is not in order because ConcurrentDictionary, like Dictionary, is unordered.  Also note that both E and F show the value 6.  This is because the output task reached F before the update, but the updates for the rest of the items occurred before their output (probably because console output is very slow, comparatively). If we want to always guarantee that we will get a consistent snapshot to iterate over (that is, at the point we ask for it we see precisely what is in the dictionary and no subsequent updates during iteration), we should iterate over a call to ToArray() instead: 1: // attempt iteration in a separate thread 2: var iterationTask = new Task(() => 3: { 4: // iterates using a dirty read 5: foreach (var pair in dictionary.ToArray()) 6: { 7: Console.WriteLine(pair.Key + ":" + pair.Value); 8: } 9: }); The atomic Try…() methods As you can imagine TryAdd() and TryRemove() have few surprises.  Both first check the existence of the item to determine if it can be added or removed based on whether or not the key currently exists in the dictionary: 1: // try add attempts an add and returns false if it already exists 2: if (dictionary.TryAdd("G", 7)) 3: Console.WriteLine("G did not exist, now inserted with 7"); 4: else 5: Console.WriteLine("G already existed, insert failed."); TryRemove() also has the virtue of returning the value portion of the removed entry matching the given key: 1: // attempt to remove the value, if it exists it is removed and the original is returned 2: int removedValue; 3: if (dictionary.TryRemove("C", out removedValue)) 4: Console.WriteLine("Removed C and its value was " + removedValue); 5: else 6: Console.WriteLine("C did not exist, remove failed."); Now TryUpdate() is an interesting creature.  You might think from it’s name that TryUpdate() first checks for an item’s existence, and then updates if the item exists, otherwise it returns false.  Well, note quite... It turns out when you call TryUpdate() on a concurrent dictionary, you pass it not only the new value you want it to have, but also the value you expected it to have before the update.  If the item exists in the dictionary, and it has the value you expected, it will update it to the new value atomically and return true.  If the item is not in the dictionary or does not have the value you expected, it is not modified and false is returned. 1: // attempt to update the value, if it exists and if it has the expected original value 2: if (dictionary.TryUpdate("G", 42, 7)) 3: Console.WriteLine("G existed and was 7, now it's 42."); 4: else 5: Console.WriteLine("G either didn't exist, or wasn't 7."); The composite Add methods The ConcurrentDictionary also has composite add methods that can be used to perform updates and gets, with an add if the item is not existing at the time of the update or get. The first of these, AddOrUpdate(), allows you to add a new item to the dictionary if it doesn’t exist, or update the existing item if it does.  For example, let’s say you are creating a dictionary of counts of stock ticker symbols you’ve subscribed to from a market data feed: 1: public sealed class SubscriptionManager 2: { 3: private readonly ConcurrentDictionary<string, int> _subscriptions = new ConcurrentDictionary<string, int>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public void AddSubscription(string tickerKey) 7: { 8: // add a new subscription with count of 1, or update existing count by 1 if exists 9: var resultCount = _subscriptions.AddOrUpdate(tickerKey, 1, (symbol, count) => count + 1); 10:  11: // now check the result to see if we just incremented the count, or inserted first count 12: if (resultCount == 1) 13: { 14: // subscribe to symbol... 15: } 16: } 17: } Notice the update value factory Func delegate.  If the key does not exist in the dictionary, the add value is used (in this case 1 representing the first subscription for this symbol), but if the key already exists, it passes the key and current value to the update delegate which computes the new value to be stored in the dictionary.  The return result of this operation is the value used (in our case: 1 if added, existing value + 1 if updated). Likewise, the GetOrAdd() allows you to attempt to retrieve a value from the dictionary, and if the value does not currently exist in the dictionary it will insert a value.  This can be handy in cases where perhaps you wish to cache data, and thus you would query the cache to see if the item exists, and if it doesn’t you would put the item into the cache for the first time: 1: public sealed class PriceCache 2: { 3: private readonly ConcurrentDictionary<string, double> _cache = new ConcurrentDictionary<string, double>(); 4:  5: // adds a new subscription, or increments the count of the existing one. 6: public double QueryPrice(string tickerKey) 7: { 8: // check for the price in the cache, if it doesn't exist it will call the delegate to create value. 9: return _cache.GetOrAdd(tickerKey, symbol => GetCurrentPrice(symbol)); 10: } 11:  12: private double GetCurrentPrice(string tickerKey) 13: { 14: // do code to calculate actual true price. 15: } 16: } There are other variations of these two methods which vary whether a value is provided or a factory delegate, but otherwise they work much the same. Oddities with the composite Add methods The AddOrUpdate() and GetOrAdd() methods are totally thread-safe, on this you may rely, but they are not atomic.  It is important to note that the methods that use delegates execute those delegates outside of the lock.  This was done intentionally so that a user delegate (of which the ConcurrentDictionary has no control of course) does not take too long and lock out other threads. This is not necessarily an issue, per se, but it is something you must consider in your design.  The main thing to consider is that your delegate may get called to generate an item, but that item may not be the one returned!  Consider this scenario: A calls GetOrAdd and sees that the key does not currently exist, so it calls the delegate.  Now thread B also calls GetOrAdd and also sees that the key does not currently exist, and for whatever reason in this race condition it’s delegate completes first and it adds its new value to the dictionary.  Now A is done and goes to get the lock, and now sees that the item now exists.  In this case even though it called the delegate to create the item, it will pitch it because an item arrived between the time it attempted to create one and it attempted to add it. Let’s illustrate, assume this totally contrived example program which has a dictionary of char to int.  And in this dictionary we want to store a char and it’s ordinal (that is, A = 1, B = 2, etc).  So for our value generator, we will simply increment the previous value in a thread-safe way (perhaps using Interlocked): 1: public static class Program 2: { 3: private static int _nextNumber = 0; 4:  5: // the holder of the char to ordinal 6: private static ConcurrentDictionary<char, int> _dictionary 7: = new ConcurrentDictionary<char, int>(); 8:  9: // get the next id value 10: public static int NextId 11: { 12: get { return Interlocked.Increment(ref _nextNumber); } 13: } Then, we add a method that will perform our insert: 1: public static void Inserter() 2: { 3: for (int i = 0; i < 26; i++) 4: { 5: _dictionary.GetOrAdd((char)('A' + i), key => NextId); 6: } 7: } Finally, we run our test by starting two tasks to do this work and get the results… 1: public static void Main() 2: { 3: // 3 tasks attempting to get/insert 4: var tasks = new List<Task> 5: { 6: new Task(Inserter), 7: new Task(Inserter) 8: }; 9:  10: tasks.ForEach(t => t.Start()); 11: Task.WaitAll(tasks.ToArray()); 12:  13: foreach (var pair in _dictionary.OrderBy(p => p.Key)) 14: { 15: Console.WriteLine(pair.Key + ":" + pair.Value); 16: } 17: } If you run this with only one task, you get the expected A:1, B:2, ..., Z:26.  But running this in parallel you will get something a bit more complex.  My run netted these results: 1: A:1 2: B:3 3: C:4 4: D:5 5: E:6 6: F:7 7: G:8 8: H:9 9: I:10 10: J:11 11: K:12 12: L:13 13: M:14 14: N:15 15: O:16 16: P:17 17: Q:18 18: R:19 19: S:20 20: T:21 21: U:22 22: V:23 23: W:24 24: X:25 25: Y:26 26: Z:27 Notice that B is 3?  This is most likely because both threads attempted to call GetOrAdd() at roughly the same time and both saw that B did not exist, thus they both called the generator and one thread got back 2 and the other got back 3.  However, only one of those threads can get the lock at a time for the actual insert, and thus the one that generated the 3 won and the 3 was inserted and the 2 got discarded.  This is why on these methods your factory delegates should be careful not to have any logic that would be unsafe if the value they generate will be pitched in favor of another item generated at roughly the same time.  As such, it is probably a good idea to keep those generators as stateless as possible. Summary The ConcurrentDictionary is a very efficient and thread-safe version of the Dictionary generic collection.  It has all the benefits of type-safety that it’s generic collection counterpart does, and in addition is extremely efficient especially when there are more reads than writes concurrently. Tweet Technorati Tags: C#, .NET, Concurrent Collections, Collections, Little Wonders, Black Rabbit Coder,James Michael Hare

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  • Getting a key in the ActionScript Dictionary

    - by Rudy
    Hello, I am using a Dictionary in ActionScript as a queue, sort of, still reading most of the time as an associative container, but I need one time to make a loop to run through the whole dictionary, such as for (var key:String in queue) . Inside this for loop I perform some actions on an element and then call delete on that key. My issue is that I would like to wait for an Event before fetching the next element in this queue. Basically my for loop runs too fast. I would like to fetch the next key all the time, but I know there is no built in method. A solution I thought is to add a break to the loop, as the for.. in will automatically fetch the next key, but it would be a loop which always executes one time, simply to fetch the next key. This sounds a bit counter intuitive. I hope my problem makes sense and I really look for some better ideas than what I currently have. Thanks for your help! Rudy

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  • Python: Access dictionary value inside of tuple and sort quickly by dict value

    - by Aquat33nfan
    I know that wasn't clear. Here's what I'm doing specifically. I have my list of dictionaries here: dict = [{int=0, value=A}, {int=1, value=B}, ... n] and I want to take them in combinations, so I used itertools and it gave me a tuple (Well, okay it gave me a memory object that I then used enumerate on so I could loop over it and enumerate gave ma tuple): for (index, tuple) in enumerate(combinations(dict, 2)): and this is where I have my problem. I want to identify which of the two items in the combination has the bigger 'int' value and which has the smaller value and assign them to variables (I'm actually using more than 2 in the combination so I can't just say if tuple[0]['int'] tuple[1]['int'] and do the assignment because I'd have to list this out a bunch of times and that's hard to manage). I was going to assign each 'int' value to a variable, sort it in a list, index the 'int' value in the list by 1, 2, 3, 4, 5 ... etc., then go back and access the dictionary I wanted by the int value and then assign the dictionary to a variable so I knew which was bigger. But I have a big list and lists and variable assignments are resource intensive and this is taking a long time (I had only a little bit of that written and it was taking forever to run). So I was hoping someone knew a fast way to do this. I actually could list out every possible combination of assignmnets using the if/thens but it's just like 5 pages of if/thens and assignments and is hard to read and manage when I want to change it. You've probably gathered this, but I"m new at programming. thx

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  • Help with use of .NET Generics/Dictionary in replacing my Arrays

    - by Rollo R
    Hello, I have these code: Mypage.cs string[] strParameterName = new string[2] {"?FirstName", "?LastName"}; string[] strParameterValue = new string[2] {"Josef", "Stalin"}; MyConnection.MySqlLink(strConnection, strCommand, strParameterName, strParameterValue, dtTable); Myclass.cs public static void MySqlLink(string strConnection, string strCommand, string[] strParameterName, string[] strParameterValue, DataTable dtTable) { dtTable.Clear(); MySqlConnection MyConnection = new MySqlConnection(strConnection); MySqlCommand MyCommand = new MySqlCommand(strCommand, MyConnection); for (int i = 0; i < strParameterName.Length; i++) { MyCommand.Parameters.AddWithValue(strParameterName[i].ToString(), strParameterValue[i].ToString()); } MySqlDataAdapter MyDataAdapter = new MySqlDataAdapter(MyCommand); MyDataAdapter.Fill(dtTable); } And then my Sql Command will be something like "SELECT * FROM MyTable WHERE FirstName=?FirstName AND LastName=?LastName" As you can see, I am using arrays for the Parameter Name and Parameter Value and they both have to "match" with each other and ofcourse the Sql Command. Someone recommended to me that I use .NET "Dictionary" instead of arrays. Now I have never used that before. Can someone show me a relative example of how I am to use .NET Dictionary here?

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  • How do I access Dictionary items?

    - by salvationishere
    I am developing a C# VS2008 / SQL Server website app and am new to the Dictionary class. Can you please advise on best method of accomplishing this? Here is a code snippet: SqlConnection conn2 = new SqlConnection(connString); SqlCommand cmd = conn2.CreateCommand(); cmd.CommandText = "dbo.AppendDataCT"; cmd.CommandType = CommandType.StoredProcedure; cmd.Connection = conn2; SqlParameter p1, p2, p3; foreach (string s in dt.Rows[1].ItemArray) { DataRow dr = dt.Rows[1]; // second row p1 = cmd.Parameters.AddWithValue((string)dic[0], (string)dr[0]); p1.SqlDbType = SqlDbType.VarChar; p2 = cmd.Parameters.AddWithValue((string)dic[1], (string)dr[1]); p2.SqlDbType = SqlDbType.VarChar; p3 = cmd.Parameters.AddWithValue((string)dic[2], (string)dr[2]); p3.SqlDbType = SqlDbType.VarChar; } but this is giving me compiler error: The best overloaded method match for 'System.Collections.Generic.Dictionary<string,string>.this[string]' has some invalid arguments I just want to access each value from "dic" and load into these SQL parameters. How do I do this? Do I have to enter the key? The keys are named "col1", "col2", etc., so not the most user-friendly. Any other tips? Thanks!

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  • Alternative of custom attrbutes for tags to store some information in HTML 4

    - by Ashwani K
    Hello All: Can some body tell me any alternative to store some information for a particular tag in HTML 4. For example If I have a drop down like <select> <option value="0" regionId="1">Test1</option> <option value="1" regionId="2">Test2</option> </select> Here regionId is a custom attribute, I am able to access the attribute but the W3C HTML validation is failing. Any suggestion on this?

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  • Making my own custom Ubuntu

    - by Benny
    I was wondering, is it possible to make my own customized version of Linux based on Ubuntu 10.10 ? I am thinking of calling it something different but I was wondering besides making a custom Live CD I am talking about an Linux that people can install on there computers using Ubuntu installation method. I want to base it on something other than GNOME but be able to install it latter on. Thanks in advance, Benny

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  • Difference between OEM install and custom Ubuntu image

    - by Suman
    I'm looking into the best way to deploy a customized Ubuntu image and it looks like I have two options: To make an "OEM install" version To make a custom Ubuntu image Could someone help me understand the difference between these two methods of customizing a Ubuntu install? It appears to me that both these methods allow for elaborate customization of the image while allowing the user to enter their own end-user details (time zone, username, password, etc.)

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  • What is a good way to keep track of strings for dictionary lookups?

    - by Justin
    I am working through the Windows 8 app tutorial. They have some code about saving app data like so: private void NameInput_TextChanged(object sender, TextChangedEventArgs e) { Windows.Storage.ApplicationDataContainer roamingSettings = Windows.Storage.ApplicationData.Current.RoamingSettings; roamingSettings.Values["userName"] = nameInput.Text; } I have worked with C# in the past and found that things like using constant string values (like "userName" in this case) for keys could get messy because auto-complete did not work and it was easy to forget if I had made an entry for a setting before and what it was called. So if I don't touch code for awhile I end up accidentally creating multiple entries for the same value that are named slightly differently. Surely there is a better way to keep track of the strings that key to those values. What is a good solution to this problem?

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