Actually, it&#39;s quite simple with Swift. As mentioned in the [Apple&#39;s doc][1], you can initialize an array with the same repeated value like this:

With **old Swift version**:

    var threeDoubles = [Double](count: 3, repeatedValue: 0.0)

Since **Swift 3.0**:

    var threeDoubles = [Double](repeating: 0.0, count: 3)

which would give:

    [0.0, 0.0, 0.0]


  [1]: https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/CollectionTypes.html#//apple_ref/doc/uid/TP40014097-CH8-ID112

This would be an answer in Swift 3:

    var threeDoubles = [Double]( repeating: 0.0, count: 3 )

I am attempting to get the keyboard input for a command line app for the new Apple programming language Swift.

I&#39;ve scanned the docs to no avail.



    import Foundation

    println(&quot;What is your name?&quot;)
    ???

Any ideas?

Input from the keyboard in command line application

I am currently using python 2.7 and trying to open an Excel sheet.
When using the code below:
    
    import os
    from win32com.client import Dispatch
    
    xlApp = win32com.client.Dispatch(&quot;Excel.Application&quot;)
    xlApp.Visible = True
    # Open the file we want in Excel
    workbook = xlApp.Workbooks.Open(&#39;example.xls&#39;)
    
I get this error:
    
&gt;ImportError: No module named win32com.client

Is there any possibility of getting the error since I am using 64-bit Windows machine? 

ImportError: No module named win32com.client

I have a large array in Swift. I want to initialize all members to the same value (i.e. it could be zero or some other value). What would be the best approach?

How to initialize all members of an array to the same value in Swift?

<p>I have a large array in Swift. I want to initialize all members to the same value (i.e. it could be zero or some other value). What would be the best approach?</p>


Suppose I have an array, for example:


    var myArray = [&quot;Steve&quot;, &quot;Bill&quot;, &quot;Linus&quot;, &quot;Bret&quot;]



And later I want to push/append an element to the end of said array, to get:

`[&quot;Steve&quot;, &quot;Bill&quot;, &quot;Linus&quot;, &quot;Bret&quot;, &quot;Tim&quot;]`

What method should I use?

And what about the case where I want to add an element to the **front** of the array? Is there a constant time unshift?

Add an element to an array in Swift

Suppose I have an array and I want to pick one element at random.

What would be the simplest way to do this?

The obvious way would be `array[random index]`. But perhaps there is something like ruby&#39;s `array.sample`? Or if not could such a method be created by using an extension?

Pick a random element from an array

How do I randomize or shuffle the elements within an array in Swift? For example, if my array consists of 52 playing cards, I want to **shuffle** the array in order to shuffle the deck.

How do I shuffle an array in Swift?

How can I extend Swift&#39;s `Array&lt;T&gt;` or `T[]` type with custom functional utils? 

Browsing around Swift&#39;s API docs shows that Array methods are an extension of the `T[]`, e.g:

    extension T[] : ArrayType {
        //...
        init()
    
        var count: Int { get }
    
        var capacity: Int { get }
    
        var isEmpty: Bool { get }
    
        func copy() -&gt; T[]
    }

When copying and pasting the same source and trying any variations like:

    extension T[] : ArrayType {
        func foo(){}
    }

    extension T[] {
        func foo(){}
    }

It fails to build with the error:

&gt; Nominal type `T[]` can&#39;t be extended

Using the full type definition fails with `Use of undefined type &#39;T&#39;`, i.e:

    extension Array&lt;T&gt; {
        func foo(){}
    }

And it also fails with `Array&lt;T : Any&gt;` and `Array&lt;String&gt;`.

Curiously Swift lets me extend an untyped array with:

    extension Array {
        func each(fn: (Any) -&gt; ()) {
            for i in self {
                fn(i)
            }
        }
    }

Which it lets me call with:

    [1,2,3].each(println)

But I can&#39;t create a proper generic type extension as the type seems to be lost when it flows through the method, e.g trying to [replace Swift&#39;s built-in filter with][1]:

    extension Array {
        func find&lt;T&gt;(fn: (T) -&gt; Bool) -&gt; T[] {
            var to = T[]()
            for x in self {
                let t = x as T
                if fn(t) {
                    to += t
                }
            }
            return to
        }
    }

But the compiler treats it as untyped where it still allows calling the extension with: 

    [&quot;A&quot;,&quot;B&quot;,&quot;C&quot;].find { $0 &gt; &quot;A&quot; }

And when stepped-thru with a debugger indicates the type is `Swift.String` but it&#39;s a build error to try access it like a String without casting it to `String` first, i.e:

    [&quot;A&quot;,&quot;B&quot;,&quot;C&quot;].find { ($0 as String).compare(&quot;A&quot;) &gt; 0 }

Does anyone know what&#39;s the proper way to create a typed extension method that acts like the built-in extensions?


  [1]: https://stackoverflow.com/q/24025633/85785


How can I extend typed Arrays in Swift?

Is there a function that I can use to iterate over an array and have both index and element, like Python&#39;s `enumerate`?

    for index, element in enumerate(list):
        ...


How to iterate a loop with index and element in Swift

Consider the two classes:

    class A {
    	var x: Int
    	
    	init(x: Int) {
    		self.x = x
    	}
    	
    	convenience init() {
    		self.init(x: 0)
    	}
    }
    
    class B: A {
    	init() {
    		super.init() // Error: Must call a designated initializer of the superclass &#39;A&#39;
    	}
    }

I don&#39;t see why this isn&#39;t allowed. Ultimately, each class&#39;s designated initializer is called with any values they need, so why do I need to repeat myself in `B`&#39;s `init` by specifying a default value for `x` again, when the convenience `init` in `A` will do just fine?

Why can&#39;t Swift initializers call convenience initializers on their superclass?

With C++11, we now have the ability to initialize class members in a header declaration:

    class aClass
    {
    	private:
    		int mInt{100};
    	public:
    		 aClass();
    		~aClass();
    };

So I&#39;m a bit confused. Traditionally initialization lists in constructors have been used for member initialization:

    aClass::aClass()
    : mInt(100)
    {
    	...
    }


Has the new C++11 member initialization feature at declaration made initialization lists obsolete? If not, what are the advantages of one over the other? What situations would make initialization at declaration advantageous, or initialization lists advantageous? When should one be used over the other?




Has the new C++11 member initialization feature at declaration made initialization lists obsolete?

Suppose I have the following:

    #include &lt;memory&gt;
    struct A { int x; };

    class B {
      B(int x, std::unique_ptr&lt;A&gt; a);
    };
    
    class C : public B {
      C(std::unique_ptr&lt;A&gt; a) : B(a-&gt;x, std::move(a)) {}
    };



If I understand the C++ rules about &quot;unspecified order of function parameters&quot; correctly, this code is unsafe. If the second argument to `B`&#39;s constructor is constructed first using the move constructor, then `a` now contains a `nullptr` and the expression `a-&gt;x` will trigger undefined behavior (likely segfault). If the first argument is constructed first, then everything will work as intended.

If this were a normal function call, we could just create a temporary:

    auto x = a-&gt;x
    B b{x, std::move(a)};

But in the class initialization list we don&#39;t have the freedom to create temporary variables.

Suppose I cannot change `B`, is there any possible way to accomplish the above? Namely dereferencing and moving a `unique_ptr` in the same function call expression without creating a temporary?

What if you could change `B`&#39;s constructor but not add new methods such as `setX(int)`? Would that help?

Thank you


Move semantics and function order evaluation

To the best of my knowledge, there are three ways to initialize a variable in C++.

    int x = 0;    // C-like initialization
    int x (0);    // Constructor initialization
    int x {0};    // Uniform initialization

The uniform initialization was brought on for [C++11][1] to provide a more uniform syntax for initializing different types of variables, which required different syntax in [C++03][2].

What are the differences between C-like, constructor, and uniform initialization? And should I always use the uniform initialization?

  [1]: https://en.wikipedia.org/wiki/C%2B%2B11
  [2]: https://en.wikipedia.org/wiki/C%2B%2B03



What are the differences between C-like, constructor, and uniform initialization?

How do you add custom initializers to `UIViewController` subclasses in Swift?

I&#39;ve created a sub class of `UIViewController` that looks something like this:

    class MyViewController : UIViewController
    {
    	init(leftVC:UIViewController, rightVC:UIViewController, gap:Int)
    	{
    		self.leftVC = leftVC;
    		self.rightVC = rightVC;
    		self.gap = gap;
    		
    		super.init();
    		
    		setupScrollView();
    		setupViewControllers();
    	}
    }

When I run it I get a fatal error:

&gt; fatal error: use of unimplemented initializer &#39;init(nibName:bundle:)&#39; for class &#39;MyApp.MyViewController&#39;

I&#39;ve read elewhere that when adding a custom initializer one has to also override `init(coder aDecoder:NSCoder)` so let&#39;s override that `init` and see what happens:

	override init(coder aDecoder: NSCoder)
	{
		super.init(coder: aDecoder);
	}

If I add this, Xcode complains that `self.leftVC is not initialized at super.init call`. So I guess that can&#39;t be the solution either. So I wonder how can I add custom initializers properly to a `ViewController` subclass in Swift (since in Objective-C this seems not to be a problem)?

Swift: Custom ViewController initializers

What is the difference between `let` and `var` in Apple&#39;s Swift language?

In my understanding, it is a compiled language but it does not check the type at compile time. It makes me confused. How does the compiler know about the type error? If the compiler doesn&#39;t check the type, isn&#39;t it a problem with production environment?

This error is given when I try to assign a value to a `let`:

 &gt; Cannot assign to property: &#39;variableName&#39; is a &#39;let&#39; constant  
 &gt; Change &#39;let&#39; to &#39;var&#39; to make it mutable


What is the difference between `let` and `var` in Swift?

In Swift, how does one call Objective-C code?

Apple mentioned that they could co-exist in one application, but does this mean that one could technically re-use old classes made in Objective-C whilst building new classes in Swift?

How do I call Objective-C code from Swift?

In swift there seem to be two equality operators: the double equals (**`==`**) and the triple equals (**`===`**), what is the difference between the two?

Difference between == and ===

The documentation only mentions nested types, but it&#39;s not clear if they can be used as namespaces. I haven&#39;t found any explicit mentioning of namespaces.

Content Type	Original Author	Original Content on Stackoverflow
Question	m_power	View Question on Stackoverflow
Solution 1 - Arrays	moumoute6919	View Answer on Stackoverflow
Solution 2 - Arrays	arauter	View Answer on Stackoverflow

How to initialize all members of an array to the same value in Swift?

Arrays Problem Overview

Arrays Solutions

Solution 1 - Arrays

Solution 2 - Arrays

ImportError: No module named win32com.client

Input from the keyboard in command line application

Attributions