The only difference between `weak` and `assign` is that if the object a `weak` property points to is deallocated, then the value of the `weak` pointer will be set to `nil`, so that you never run the risk of accessing garbage. If you use `assign`, that won&#39;t happen, so if the object gets deallocated from under you and you try to access it, you will access garbage.

For Objective-C objects, if you&#39;re in an environment where you can use `weak`, then you should use it.

I have a list of about 100 igraph objects with a typical object having about 700 vertices and 3500 edges.

I would like to identify groups of vertices within which ties are more likely.  My plan is to then use a mixed model to predict how many within-group ties vertices have using vertex and group attributes.

Some people may want to respond to other aspects of my project, which would be great, but the thing I&#39;m most interested in is information about functions in igraph for grouping vertices.  I&#39;ve come across these [community detection algorithms][1] but I&#39;m not sure of their advantages and disadvantages, or whether some other function would be better for my case.  I saw the links [here][2] as well, but they aren&#39;t specific to igraph.  Thanks for your advice.


  [1]: http://igraph.sourceforge.net/doc/R/community.structure.html
  [2]: https://stackoverflow.com/a/5823371/303400

What are the differences between community detection algorithms in igraph?

    a &lt;- c(1, 2, 0, 3, 7)

I am looking for a function to return the index of the smallest value, 3. What is it?

Return index of the smallest value in a vector?

Whats the difference between this:

    @property (nonatomic, weak) id  &lt;SubClassDelegate&gt; delegate; 

and this:

    @property (nonatomic, assign) id  &lt;SubClassDelegate&gt; delegate; 

I want to use property for delegates.

What&#39;s the difference between &#39;weak&#39; and &#39;assign&#39; in delegate property declaration

Whats the difference between this:
<pre><code class="hljs language-objectivec">@property (nonatomic, weak) id &#x3C;SubClassDelegate> delegate; 
</code></pre>
and this:
<pre><code class="hljs language-objectivec">@property (nonatomic, assign) id &#x3C;SubClassDelegate> delegate; 
</code></pre>
I want to use property for delegates.

I have set my UIToolBar tint color to some value, and there is this border line that I see in which I want to remove:

![enter image description here][1]


  [1]: http://i.stack.imgur.com/VsVdE.png

How do I remove this black border&gt;

how can I remove the top border on UIToolBar

I&#39;ve been doing iOS development for a couple of months now and just learned of the promising [CocoaPods][1] library for dependency management.

I tried it out on a personal project: added a dependency to [Kiwi][2] to my Podfile, ran `pod install CocoaPodsTest.xcodeproj`, and *voila*, it worked great.

The only thing I&#39;m left wondering is: what do I check in, and what do I ignore for version control? It seems obvious that I want to check in the Podfile itself, and probably the .xcworkspace file as well; but do I ignore the Pods/ directory? Are there other files that will be generated down the road (when I add other dependencies) that I should also add to my .gitignore?

  [1]: http://cocoapods.org/
  [2]: https://github.com/allending/Kiwi

What goes into your .gitignore if you&#39;re using CocoaPods?

How do I make a UIScrollView scroll to the top?

Get UIScrollView to scroll to the top

I have an array populated by dictionaries, and I need to sort the array alphabetically by the values of one of the keys of the dictionaries.

This is my array:

    tu dictus: (
        {
        brand = Ryul;
        productTitle = Any;
        quantity = 1;
        subBrand = &quot;Ryul INJ&quot;;
        type = Product;
    },
        {
        brand = Trol;
        productTitle = Different;
        quantity = 2;
        subBrand = &quot;&quot;;
        type = Brand;
    },
        {
        brand = Dtor;
        productTitle = Any;
        quantity = 1;
        subBrand = &quot;&quot;;
        type = Product;
    },
        {
        brand = Ryul;
        productTitle = Different;
        quantity = 2;
        subBrand = &quot;Ryul CHES&quot;;
        type = SubBrand;
    },
        {
        brand = Anan;
        productTitle = Any;
        quantity = 1;
        subBrand = &quot;&quot;;
        type = Product;
    }
    )


Normally for sorting an array I will use 

    myArray = [uniqueProdsArray sortedArrayUsingSelector:@selector(localizedCaseInsensitiveCompare:)];

But how do sort using the `brand` key of the dictionary?

Sorting NSArray of dictionaries by value of a key in the dictionaries

I am working on a Universal app &amp; would like to access the values stored in app-info.plist file in my code.

Reason: I instantiate a UIViewController dynamically from a storyboard using:

    UIStoryboard* storyboard = [UIStoryboard storyboardWithName:@&quot;MainStoryboard_iPhone&quot; bundle:nil];
    self = [storyboard instantiateViewControllerWithIdentifier:@&quot;ExampleViewController&quot;];

Now, having the storyboard name @&quot;MainStoryboard_iPhone&quot; above is ugly. 

I want to do something like:

    UIStoryboard* storyboard = [UIStoryboard storyboardWithName:appInfo.mainStoryboardBaseNamePhone bundle:nil];
    self = [storyboard instantiateViewControllerWithIdentifier:@&quot;ExampleViewController&quot;];

where appInfo can perhaps be an NSDictionary of all values in app-info.plist


iOS: Access app-info.plist variables in code

In an Xcode project, I see XML when clicking on MainStoryBoard.storyboard instead of the graphical design, why and how to restore the right view ?

Update: I think it&#39;s a bug of XCode 4.2 because on another project, when I click on version editor I have XML but when I click on standard editor it shows visual design.

Is there a way to fix this and not to force me to recreate my visual design by hand once again ?

Xcode 4 why do I see XML when clicking on MainStoryBoard.storyboard: seems like a bug

I&#39;m working on an app where I&#39;m going to use both HTML5 in UIWebView and native iOS framework together. I know that I can implement communication between JavaScript and Objective-C. Are there any libraries that simplify implementing this communication? I know that there are several libraries to create native iOS apps in HTML5 and javascript (for example AppMobi, PhoneGap), but I&#39;m not sure if there is a library to help create native iOS apps with heavy JavaScript usage. I need to:

 1. Execute JS methods from Objective-C
 2. Execute Objective-C methods from JS
 3. Listen to native JS events from Objective-C (for example DOM ready event)

iOS JavaScript bridge

In complex screens (View Controllers) I used to separate the whole thing in smaller pieces (I call them widgets). These widgets consist basically of a `MyWidget.h` and a `MyWidget.m` file as well as a `MyWidget.xib` file, where the root element is a `UIView` and the MyWidget class is the File Owner of the UIView. In the init of this widget I do a `loadNibNamed`.

In my View Controller I then do a `[[MyWidget alloc] init]`, which I add to View&#39;s Controller main view as a sub view. This, so far, works perfectly.

I&#39;m now wondering, how to do the same with storyboard, because I cannot really start to drag in a `UIView` somewhere, I always have to start with an `UIViewController`, which I don&#39;t want to.

If there is no possible way doing this with a Storyboard, can I simply do it the old way, by using the Storyboard for my main screens and segues, and use a separate .xib file to define custom views?

Custom views with Storyboard

Is it possible to segue from one storyboard to another, or to embed a storyboard in a view controller in another storyboard? I need to place a `UITabBarController` in a `UINavigationController`, and I&#39;d like to keep them nice and separate.

Segue to another storyboard?

I&#39;m fairly new to iOS development.

I want to add a footer to the table view in a `UITableViewController`. I&#39;ve made the view I want to use as the footer graphically in Storyboard, however I can&#39;t work out how to hook it up as the footer to my table view.

I can add a footer programmatically in `UITableViewController`&#39;s `viewDidLoad` method by assigning `self.tableView.tableFooterView`. But I&#39;ve created my footer view in Storyboard, what is the *best practice* way of adding it as the footer to my table view?

How to add a footer to a UITableView in Storyboard

I would like to use regular expression to find every instances of a regular expression pattern I.e. `&amp;*;` in my string and remove that from  so the return value is the original string without any of the matches. Also would like to use the same function to match multiple spaces between words and have a single space instead. Could not find such a function. 

Sample input string 

    NSString *str = @&quot;123 &amp;1245; Ross Test  12&quot;;

Return value should be 

    123 Ross Test 12

If anything matching this pattern `&quot;&amp;*` or multiple  white spaces and replaces it with `@&quot;&quot;;`

Use regular expression to find/replace substring in NSString

when i compile my app, Xcode just says &quot;Attaching to Projectname...&quot; and gets stuck there.
The debugger just prints this out:
&gt; error: failed to attach to process ID 0

I tried to clean &amp; build again and it still doesn&#39;t work out. I googled but couldn&#39;t find anything helpful.
How can I fix this problem? Thank You!

Xcode compiles my App, but can&#39;t run it in the simulator

im having trouble overriding the initialization method for my CustomViewController thats designed in my Storyboard.

now im doing (in my mainViewController):

    self.customViewController = [[UIStoryboard storyboardWithName:@&quot;MainStoryboard_iPhone&quot; bundle:nil] instantiateViewControllerWithIdentifier:@&quot;CustomVC&quot;];
    self.customViewController.myObject = someObject;

and i have in viewDidLoad (CustomViewController)

        [self.label setText:self.myObject.someString];

This works ok.

But, is it the correct way? Should i add a custom init method (or override) to my CustomViewController ? Like initWithObject: ? I dont know how to call my custom init method instead of `UIStoryboard instantiateViewControllerWithIdentifier:`, and im not getting calls to `init` nor `initWithNibName`.

Maybe i should use: `- (id)initWithCoder:(NSCoder *)decoder`. 

Please give me some advice!


Thank you!

viewController custom init method with storyboard

What is the general idea of a delegate in C++? What are they, how are they used and what are they used for?

I&#39;d like to first learn about them in a &#39;black box&#39; way, but a bit of information on the guts of these things would be great too.

This is not C++ at its purest or cleanest, but I notice that the codebase where I work has them in abundance. I&#39;m hoping to understand them enough, so I can just use them and not have to delve into the horrible nested template awfulness.

These two [The Code Project][1] articles explain what I mean but not particularly succinctly:

 * *[Member Function Pointers and the Fastest Possible C++ Delegates][2]*

 * *[The Impossibly Fast C++ Delegates][3]*

  [1]: http://en.wikipedia.org/wiki/The_Code_Project
  [2]: http://www.codeproject.com/Articles/7150/Member-Function-Pointers-and-the-Fastest-Possible
  [3]: http://www.codeproject.com/Articles/11015/The-Impossibly-Fast-C-Delegates


What is a C++ delegate?

Throughout my app, I&#39;m getting semantic issue warnings when I set `ViewController.delegate = self`.  I have searched and found similar posts but none were able to solve my problem.

ViewController.m:

    GameAddViewController *gameAddViewContoller = [[navigationController viewControllers] objectAtIndex:0];
    gameAddViewContoller.delegate=self;

I get the error message when setting `.delegate=self`.

GameAddViewController.h:

    @protocol GameAddViewControllerDelegate &lt;NSObject&gt;

    - (void)gameAddViewControllerDidCancel:(GameAddViewController *)controller;
    - (void)gameAddViewController:(GameAddViewController *)controller didAddGame:(Game *) game;

    @end

    @interface GameAddViewController : UITableViewController &lt;GameAddViewControllerDelegate&gt;
    {
    sqlite3         *pitchcountDB;
    NSString        *dbPath;
    }
    @property (nonatomic, strong) id &lt;GameAddViewControllerDelegate&gt; delegate;
    ...
    @end

ViewController.h:

    #import &quot;GameAddViewController.h&quot;

    @class ViewController;
    @protocol ViewControllerDelegate &lt;NSObject&gt;
    - (void)ViewControllerDidCancel:(ViewController *)controller;

    @end
    @interface ViewController : UIViewController &lt;ViewControllerDelegate&gt;
    -(void) checkAndCreateFile;
    @end


Can anyone point me in the right direction to resolve the warning messages?

Assigning to &#39;id&lt;Delegate&gt;&#39; from incompatible type &#39;ViewController *const_strong&#39;

When using `myDelegate -= eventHandler` ReSharper (version 6) issues:

&gt; Delegate subtraction has unpredictable result

The rational behind this is [explained by JetBrains here](http://confluence.jetbrains.net/display/ReSharper/Delegate+subtraction+has+unpredictable+semantics). The explanation makes sense and, after reading it, I&#39;m doubting all my uses of `-` on delegates.

*How then*, 

 - can I write a non-auto event without making ReSharper grumpy? 
 - or, is there a better and/or &quot;correct&quot; way to implement this?
 - or, can I just ignore ReSharper?

Here is simplified code:

    public delegate void MyHandler (object sender);

    MyHandler _myEvent;

    public event MyHandler MyEvent
    {
        add
        {
            _myEvent += value;
            DoSomethingElse();
        }
        remove
        {
            _myEvent -= value; // &lt;-- ReSharper warning here
        }
    }

&quot;Delegate subtraction has unpredictable result&quot; in ReSharper/C#?

What is the difference between Invoke and DynamicInvoke in delegates? Please give me some code example which explain difference between that two methods.


Difference Between Invoke and DynamicInvoke

In C# language and .NET framework, could you help me with understanding delegates?
I was trying to check some code, and found that the results I received were unexpected for me. Here it is:

    class Program
    {
        public static int I = 0;
        
        static Func&lt;string&gt; del = new Func&lt;string&gt;(I.ToString);
       
        static void Main(string[] args)
        {
            I = 10;
            Console.WriteLine(&quot;{0}&quot;, del());
        }
    }

The answer was 0, but not 10. Why? 


Using delegates in C#

Am I right understanding that

 - `def` is evaluated every time it gets accessed

 - `lazy val` is evaluated once it gets accessed

 - `val` is evaluated once it gets into the execution scope?

`def` vs `val` vs `lazy val` evaluation in Scala

My application uses a list like this:

`List&lt;MyClass&gt; list = new List&lt;MyClass&gt;();`

Using the `Add` method, another instance of `MyClass` is added to the list.

`MyClass` provides, among others, the following methods:

    public void SetId(String Id);
    public String GetId();

How can I find a specific instance of `MyClass` by means of using the `GetId` method? I know there is the `Find` method, but I don&#39;t know if this would work here?!


How can I find a specific element in a List&lt;T&gt;?

I have a class containing several properties (all are strings if it makes any difference).  
I also have a list, which contains many different instances of the class.

While creating some unit tests for my classes I decided I wanted to loop through each object in the list and then loop through each property of that object...

I thought doing this would be as simple as...

    foreach (Object obj in theList)
    {
         foreach (Property theProperties in obj)
         {
             do some stufff!!;
         }
    }

But this didnt work! :(
I get this error...

&quot;foreach statement cannot operate on variables of type &#39;Application.Object&#39; because &#39;Application.Object&#39; does not contain a public definition for &#39;GetEnumerator&#39;&quot;

Does anyone know of a way of doing this without tons of ifs and loops or without getting into anything too complex?

c# foreach (property in object)... Is there a simple way of doing this?

What I&#39;m trying to do is setting the value of the property in a class using a string.  For example, my class has the following properties:

    myClass.Name
    myClass.Address
    myClass.PhoneNumber
    myClass.FaxNumber

All the fields are of `string` type so I know ahead of time that it&#39;s always a string.  Now, I want to be able to set the properties using a string as you could do with a `DataSet` object.  Something like this:

    myClass[&quot;Name&quot;] = &quot;John&quot;
    myClass[&quot;Address&quot;] = &quot;1112 River St., Boulder, CO&quot;

Ideally, I want to just assign a variable and then set the property using that string name from the variable:

    string propName = &quot;Name&quot;
    myClass[propName] = &quot;John&quot;

I was reading about reflection and maybe it&#39;s the way to do it but I&#39;m not sure how to go about setting that up while keeping the property access intact in the class.  I want to still be able to use:

    myClass.Name = &quot;John&quot;

Any code examples would be really great.

Setting/getting the class properties by string name

I am using `json_decode()` something like:

    $myVar = json_decode($data)

Which gives me output like this:

    [highlighting] =&gt; stdClass Object
            (
                [448364] =&gt; stdClass Object
                    (
                        [Data] =&gt; Array
                            (
                                [0] =&gt; Tax amount liability is ....... 


I want to access the string value in the key [0]. When I try to do something like:

    print $myVar-&gt;highlighting-&gt;448364-&gt;Data-&gt;0;

I get this error:

&gt; Parse error: syntax error, unexpected T_DNUMBER

The two numerals/integers there seems to be problem.


Content Type	Original Author	Original Content on Stackoverflow
Question	Firdous	View Question on Stackoverflow
Solution 1 - Objective C	yuji	View Answer on Stackoverflow

What's the difference between 'weak' and 'assign' in delegate property declaration

Objective C Problem Overview

Objective C Solutions

Solution 1 - Objective C

Return index of the smallest value in a vector?

What are the differences between community detection algorithms in igraph?

Attributions