 - Launch Xcode 6
 - Documentation and API Reference Window (command-shift-0)
 - Search for “The Swift Programming Language”
 - Click first suggestion

You will see a series of collapsable menus on the left side of the screen detailing different sections, such as “A Swift Tour”, and “Language Guide”. You can click through these to get different bits of information about different aspects of the language.

Many sections will feature the “Open Playground” links that you’ve described, except from here, they’re clickable. When you click one of these &quot;Open Playground&quot; links, the `.playground` file associated with this section will be downloaded to your downloads folder, and can be directly opened with Xcode 6.


![enter image description here][1]

There is even another option that allows you to open the playground files directly without first dropping them in your downloads folder.

In the documentation viewer in Xcode 6, search for &quot;A Swift Tour&quot;, or any other term that you find to yield you an article you&#39;re looking for:

![enter image description here][2]

Click a result that has a .playground icon to its left. From here, you can use the &quot;Action&quot; button on the right side of the window to open the file directly in an Xcode Playground.

![enter image description here][3]


  [1]: http://i.stack.imgur.com/gJeCl.png
  [2]: http://i.stack.imgur.com/rAnzw.png
  [3]: http://i.stack.imgur.com/65ITn.png

It&#39;s simple, open the book on your Mac or iPad, you will see a &quot;Download playground&quot; link just bellow that statement &quot;open this chapter as a playground in Xcode&quot;. You have to download that playground and open it, that&#39;s all.

I was tricked because I thought I don&#39;t need to download the playground since I already had Xcode installed, apparently I should do it.

I have bunch of files sitting in folders like

    data\A\A\A\json1.json
    data\A\A\A\json2.json
    data\A\A\B\json1.json
    ...
    data\Z\Z\Z\json_x.json

I want to cat all the jsons into one single file?


Recursively cat all the files into single file

I have a simple form. All of the components and state are held in the Page component. There are 2 display headers and 3 input fields. The first input is supposed to be text, and the second and third are supposed to be ints. When the user inputs the wrong type of data, I want to have an error message pop up next to the input field. My questions relate to best practices in React.JS

Who decides that the value is in valid? I suppose that the only job of the input field is to direct the value back to component holding the state, so does this mean that only Page can determine if a value is valid?

How should I then have the pop up appear? Should Page have to trigger a new boolean state element that will be passed through perp that will tell Adaptive_Input to reveal the error message?

[JSFiddle][1]

**JS:**

    /**
     * @jsx React.DOM
     */
    var Adaptive_Input = React.createClass({ 
    	handle_change: function(){
    		var new_text = this.refs.input.getDOMNode().value;
    		this.props.on_Input_Change(new_text);
    	},
    	render: function(){
    		return (
    				&lt;div className=&#39;adaptive_placeholder_input_container&#39;&gt;
    					&lt;input 
    						className=&quot;adaptive_input&quot;
    						type=&quot;text&quot; 
    						required=&quot;required&quot; 
    						onChange= {this.handle_change}
    						ref=&quot;input&quot;
    					&gt;&lt;/input&gt;
    					&lt;label
    						className=&quot;adaptive_placeholder&quot;
    						alt={this.props.initial}
    						placeholder={this.props.focused}
    					&gt;&lt;/label&gt;
    				&lt;/div&gt;    			
    				);
    	}
    });
    
    var Form = React.createClass({
    	render: function(){
    		return (
    				&lt;form&gt;
    					&lt;Adaptive_Input
    						initial={&#39;Name Input&#39;}
    						focused={&#39;Name Input&#39;}
    						on_Input_Change={this.props.handle_text_input}
    					/&gt;
    					&lt;Adaptive_Input
    						initial={&#39;Value 1&#39;}
    						focused={&#39;Value 1&#39;}
    						on_Input_Change={this.props.handle_value_1_input}
    					/&gt;
    					&lt;Adaptive_Input
    						initial={&#39;Value 2&#39;}
    						focused={&#39;Value 2&#39;}
    						on_Input_Change={this.props.handle_value_2_input}
    					/&gt;
    				&lt;/form&gt;
    				);
    	}
    });
    
    var Page = React.createClass({
    	getInitialState: function(){
    		return {
    			Name : &quot;No Name&quot;,
    			Value_1 : &#39;0&#39;,
    			Value_2 : &#39;0&#39;,
    			Display_Value: &#39;0&#39;
    		};
    	},
    	handle_text_input: function(new_text){
    		this.setState({
    				Name: new_text
    			});
    	},
    	handle_value_1_input: function(new_value){
    		console.log(&quot;===&quot;);
    		var updated_display = parseInt(new_value) + parseInt(this.state.Value_2);
    		updated_display = updated_display.toString();
    		this.setState({
    				Display_Value: updated_display 
    			});
    	},
    	handle_value_2_input: function(new_value){
    		var updated_display = parseInt(this.state.Value_1) + parseInt(new_value);
    		updated_display = updated_display.toString();
    		this.setState({
    				Display_Value: updated_display
    			});
    	},
    	render: function(){
    		return(
    				&lt;div&gt;
    					&lt;h2&gt;{this.state.Name}&lt;/h2&gt;
    					&lt;h2&gt;Value 1 + Value 2 = {this.state.Display_Value}&lt;/h2&gt;
    					&lt;Form
    						handle_text_input={this.handle_text_input}
    						handle_value_1_input = {this.handle_value_1_input}
    						handle_value_2_input = {this.handle_value_2_input}
    					/&gt;
    				&lt;/div&gt;
    		);
    	}
    });
    
    React.renderComponent(&lt;Page /&gt;, document.body);


  [1]: http://jsfiddle.net/easilyBaffled/bgC6E/1/

How to properly validate input values with React.JS?

I have the Swift book open in iBooks, and see the note “For the best experience, open this chapter as a playground in Xcode.”  How is this done?

How do I &quot;open this chapter as a playground in Xcode&quot;?

<p>I have the Swift book open in iBooks, and see the note “For the best experience, open this chapter as a playground in Xcode.”  How is this done?</p>


When trying to connect a Navigation Bar Button to the Exit item of a ViewController in Xcode 6 (not really sure if it&#39;s an Xcode 6 problem but worth mentioning as it is in beta) it does not find the Swift function in the custom class.

![Button to Exit with whip][1]

The function it should be finding:

    @IBAction func unwindToList(segue: UIStoryboardSegue) {
    
    }


I made another button on the view just to make sure I could get an IBAction working with Swift and that I was writing it correctly. This works fine:

    @IBAction func test(sender: AnyObject) {
    
        NSLog(&quot;Test&quot;)
    }

I have seen [this question](https://stackoverflow.com/questions/12792573/cannot-connect-storyboard-unwind-segue) that seems like the same issue but according to the answers there this should be working.

Xcode 6 is in beta and, of course, Swift is very new, but wanted to see if anyone has come across this before considering it a potential bug. 


  [1]: http://i.stack.imgur.com/x2CBT.png

Xcode 6 Storyboard Unwind Segue with Swift Not Connecting to Exit

I am unable to launch my app on simulator using Xcode 6 beta and iPhone 5s simulator.
First I am getting an error message from Simulator
&gt; &quot;Unable to boot the iOS simulator&quot;

and then after Xcode is showing me following error,
&gt;**Unable to run app in Simulator**  
&gt;An error was encountered while running (Domain = DTiPhoneSimulatorErrorDomain, Code = 2)

![Xcode Error][1]


  [1]: https://i.stack.imgur.com/CNw2d.png

Unable to run app in Simulator: Xcode beta 6 iOS 8

How do you get the length of a `String`? For example, I have a variable defined like:

    var test1: String = &quot;Scott&quot;

However, I can&#39;t seem to find a length method on the string.



Get the length of a String

I&#39;m trying to ultimately have an `NSMutableURLRequest` with a valid `HTTPBody`, but I can&#39;t seem to get my string data (coming from a `UITextField`) into a usable `NSData` object.

I&#39;ve seen this method for going the other way:

    NSString(data data: NSData!, encoding encoding: UInt)

But I can&#39;t seem to find any documentation for my use case. I&#39;m open to putting the string into some other type if necessary, but none of the initialization options for `NSData` using Swift seem to be what I&#39;m looking for.

Creating NSData from NSString in Swift

In **Xcode5** there is simple option to Delete derived data:

In organiser menu (&lt;kbd&gt;cmd&lt;/kbd&gt; + &lt;kbd&gt;shift&lt;/kbd&gt; + &lt;kbd&gt;2&lt;/kbd&gt;):

![enter image description here][1]


But with new interface of Xcode6 there is no similar options.

Is there any quick methods to delete this trough **Xcode6** interface?

Or now I should remove this folders in system manually?

  [1]: https://i.stack.imgur.com/a0D2G.png

How to &quot;Delete derived data&quot; in Xcode?

I am trying to find an `item index` by searching a `list`. Does anybody know how to do that? 

I see there is `list.StartIndex` and `list.EndIndex` but I want something like python&#39;s `list.index(&quot;text&quot;)`.

How to find index of list item in Swift?

It&#39;s time to admit defeat...

In Objective-C, I could use something like:  

    NSString* str = @&quot;abcdefghi&quot;;
    [str rangeOfString:@&quot;c&quot;].location; // 2

In Swift, I see something similar:  

    var str = &quot;abcdefghi&quot;
    str.rangeOfString(&quot;c&quot;).startIndex
    
...but that just gives me a `String.Index`, which I can use to subscript back into the original string, but not extract a location from. 

FWIW, that `String.Index` has a private ivar called `_position` that has the correct value in it. I just don&#39;t see how it&#39;s exposed.

I know I could easily add this to String myself. I&#39;m more curious about what I&#39;m missing in this new API.

Finding index of character in Swift String

I can do this:

    var a = [1,5,7,9,22]
    a.count               // 5
    a[a.count - 1]        // 22
    a[a.endIndex - 1]     // 22
 

but surely there&#39;s a prettier way?

How do I fetch the last element of an array in Swift?

How do you access command line arguments for a command line application in Swift?

How do you access command line arguments in Swift?

Assume a setup like this:

 - You have an Xcode 6 project, where you&#39;ve implemented your own classes (say MyView and MyViewController) with both Objective-C and Swift
 - You have added a Playground into your project

In the Playground, it&#39;s possible to import modules (frameworks) like `UIKit` with the `import` keyword. How do you enable access to the project&#39;s other classes from the Playground?

Just trying to access project classes directly results with an error message:
*Use of unresolved identifier &#39;MyView&#39;*

How to import own classes from your own project into a Playground

Many Cocoa and CocoaTouch methods have completion callbacks implemented as blocks in Objective-C and Closures in Swift.  However, when trying these out in Playground, the completion is never called.  For example:

    // Playground - noun: a place where people can play

    import Cocoa
    import XCPlayground

    let url = NSURL(string: &quot;http://stackoverflow.com&quot;)
    let request = NSURLRequest(URL: url)

    NSURLConnection.sendAsynchronousRequest(request, queue:NSOperationQueue.currentQueue() {
	response, maybeData, error in

        // This block never gets called?
	    if let data = maybeData {
		    let contents = NSString(data:data, encoding:NSUTF8StringEncoding)
		    println(contents)
	    } else {
		    println(error.localizedDescription)
	    }
    }

I can see the console output in my Playground timeline, but the `println` in my completion block are never called...    

How do I run Asynchronous callbacks in Playground

I am working with Xcode 6, and I&#39;m trying to recreate the code demoed during session 401 &quot;What&#39;s new in Xcode 6&quot;. I&#39;ve added an image to Images.xcassets (called Sample) and within the playground file I&#39;m trying to access this image, as demoed.

My code is as follows (like the demo):

    var sample = UIImage(named: &quot;Sample&quot;)

However, I can&#39;t get it to work like the demo. Am I missing something?

Swift playgrounds with UIImage

When I use the for loop in Playground, everything worked fine, until I changed the first parameter of for loop to be the highest value. (iterated in descending order)


Is this a bug? Did any one else have it?

    for index in 510..509
    {
        var a = 10
    }

The counter that displays the number of iterations that will be executions keeps ticking...

![enter image description here][1]


  [1]: http://i.stack.imgur.com/FTvt4.png

How to iterate for loop in reverse order in swift?

How do I make a UIImageView with rounded corners on a Swift iOS Playground?&lt;br&gt;
Inside it needs to be filled with a color.

Content Type	Original Author	Original Content on Stackoverflow
Question	vonlost	View Question on Stackoverflow
Solution 1 - Xcode	Mick MacCallum	View Answer on Stackoverflow
Solution 2 - Xcode	Tiberiu Oprea	View Answer on Stackoverflow

How do I "open this chapter as a playground in Xcode"?

Xcode Problem Overview

Xcode Solutions

Solution 1 - Xcode

Solution 2 - Xcode

How to properly validate input values with React.JS?

Recursively cat all the files into single file

Attributions