&lt;!-- language: lang-none --&gt;

    Literal     Type              Value
    
    #file       String	          The path to the file in which it appears.
    #fileID     String	          The name of the file and module in which it appears.
    #filePath   String	          The path to the file in which it appears.
    #line       Int	              The line number on which it appears.
    #column     Int	              The column number in which it begins.
    #function   String            The name of the declaration in which it appears.
    #dsohandle  UnsafeRawPointer  The dynamic shared object (DSO) handle in use where it appears.


[See documentation for more information
][1] 

Example: 
```swift
print(&quot;Function: \(#function), line: \(#line)&quot;) 
```

With default values in parameters you can also create a function:

```swift
public func track(_ message: String, file: String = #file, function: String = #function, line: Int = #line ) { 
    print(&quot;\(message) called from \(function) \(file):\(line)&quot;) 
}
```

which can be used like this

```swift
track(&quot;enters app&quot;)
``` 

  [1]: https://docs.swift.org/swift-book/ReferenceManual/Expressions.html#ID390

The [Swift Language Reference defines][1] a few &quot;special literals&quot; that offer this behavior:

&lt;!-- language: lang-none --&gt;

    Literal        Type     Value
  
    #file          String   The name of the file in which it appears.
    #line          Int      The line number on which it appears.
    #column        Int      The column number in which it begins.
    #function      String   The name of the declaration in which it appears.

[1]: https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/Expressions.html#//apple_ref/doc/uid/TP40014097-CH32-ID390

You can get just the file name this way

Swift 5
-------

    let errorLocation =  (#file as NSString).lastPathComponent
    print(errorLocation)
    
or get with separator from last component

    let errorLocation = filePath.components(separatedBy: &quot;/&quot;).last!
    print(errorLocation)

Output
------

 

    ViewController.swift

I have the following data frame which I called ozone:

       Ozone Solar.R Wind Temp Month Day
    1     41     190  7.4   67     5   1
    2     36     118  8.0   72     5   2
    3     12     149 12.6   74     5   3
    4     18     313 11.5   62     5   4
    5     NA      NA 14.3   56     5   5
    6     28      NA 14.9   66     5   6
    7     23     299  8.6   65     5   7
    8     19      99 13.8   59     5   8
    9      8      19 20.1   61     5   9

I would like to extract the highest value from `ozone`, `Solar.R`, `Wind`...

Also, if possible how would I sort `Solar.R` or any column of this data frame in descending order

I tried 

    max(ozone, na.rm=T)

which gives me the highest value in the dataset.

I have also tried 

    max(subset(ozone,Ozone))
 
but got `&quot;subset&quot; must be logical.&quot;`

I can set an object to hold the subset of each column, by the following commands

    ozone &lt;- subset(ozone, Ozone &gt;0)
    max(ozone,na.rm=T) 

but it gives the same value of 334, which is the max value of the data frame, not the column.

Any help would be great, thanks.

How to find the highest value of a column in a data frame in R?

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?

In Objective-C, we could use the `__LINE__` and `__PRETTY_FUNCTION__` macros.  These are not exposed in the Swift language.  Is there another way to get similar information in Swift?

Is there a way to get line number and function name in Swift language?

<p>In Objective-C, we could use the <code>__LINE__</code> and <code>__PRETTY_FUNCTION__</code> macros.  These are not exposed in the Swift language.  Is there another way to get similar information in Swift?</p>


There is no `main()` method in swift. The program must start the execution from somewhere. So what is the entry point of swift code execution and how is it decided?

What is the entry point of swift code execution?

Since swift does not fallthrough `case` statements in `switch`, How can I write an empty case statement without getting an error?

    let a = 50
    switch a {
    case 0..10:
    case 10..100:
        println(&quot;between 10 and 100&quot;)
    default:
        println(&quot;100 and above&quot;)
    }

How can I make the first case stop the switch?

How can I write an empty case in Swift?

In Objective-C, one can add a `description` method to their class to aid in debugging:

    @implementation MyClass
    - (NSString *)description
    {
        return [NSString stringWithFormat:@&quot;&lt;%@: %p, foo = %@&gt;&quot;, [self class], foo _foo];
    }
    @end

Then in the debugger, you can do:

    po fooClass
    &lt;MyClass: 0x12938004, foo = &quot;bar&quot;&gt;

What is the equivalent in Swift? Swift&#39;s REPL output can be helpful:

      1&gt; class MyClass { let foo = 42 }
      2&gt; 
      3&gt; let x = MyClass()
    x: MyClass = {
      foo = 42
    }

But I&#39;d like to override this behavior for printing to the console:

      4&gt; println(&quot;x = \(x)&quot;)
    x = C11lldb_expr_07MyClass (has 1 child)

Is there a way to clean up this `println` output? I&#39;ve seen the `Printable` protocol:

    /// This protocol should be adopted by types that wish to customize their
    /// textual representation.  This textual representation is used when objects
    /// are written to an `OutputStream`.
    protocol Printable {
        var description: String { get }
    }

I figured this would automatically be &quot;seen&quot; by `println` but it does not appear to be the case:

      1&gt; class MyClass: Printable {
      2.     let foo = 42
      3.     var description: String { get { return &quot;MyClass, foo = \(foo)&quot; } }
      4. }   
      5&gt; 
      6&gt; let x = MyClass()
    x: MyClass = {
      foo = 42
    }
      7&gt; println(&quot;x = \(x)&quot;)
    x = C11lldb_expr_07MyClass (has 1 child)

And instead I have to explicitly call description:

     8&gt; println(&quot;x = \(x.description)&quot;)
    x = MyClass, foo = 42

Is there a better way?


What is the Swift equivalent of -[NSObject description]?

I&#39;m finding Swift numerics particularly clumsy when, as so often happens in real life, I have to communicate with Cocoa Touch with regard to CGRect and CGPoint (e.g., because we&#39;re talking about something&#39;s `frame` or `bounds`).

### CGFloat vs. Double

Consider the following innocent-looking code from a UIViewController subclass:

    let scale = 2.0
    let r = self.view.bounds
    var r2 = CGRect()
    r2.size.width = r.size.width * scale

This code fails to compile, with the usual mysterious error on the last line:

&gt; Could not find an overload for &#39;*&#39; that accepts the supplied arguments

This error, as I&#39;m sure you know by now, indicates some kind of impedance mismatch between types. `r.size.width` arrives as a CGFloat, which will interchange automatically with a Swift Float but cannot interoperate with a Swift Double variable (which, by default, is what `scale` is).

The example is artificially brief, so there&#39;s an artificially simple solution, which is to cast `scale` to a Float from the get-go. But when many variables drawn from all over the place are involved in the calculation of a proposed CGRect&#39;s elements, there&#39;s a lot of casting to do.

### Verbose Initializer

Another irritation is what happens when the time comes to create a new CGRect. Despite the documentation, there&#39;s no initializer with values but without labels. This fails to compile because we&#39;ve got Doubles:

    let d = 2.0
    var r3 = CGRect(d, d, d, d)

But even if we cast `d` to a Float, we don&#39;t compile:

&gt; Missing argument labels &#39;x:y:width:height:&#39; in call

So we end up falling back on `CGRectMake`, which is no improvement on Objective-C. And sometimes CGRectMake and CGSizeMake are no improvement. Consider this actual code from one of my apps:

    let kSEP : Float = 2.0
    let intercellSpacing = CGSizeMake(kSEP, kSEP);

In one of my projects, that works. In another, it mysteriously fails — the exact same code! — with this error:

&gt; &#39;NSNumber&#39; is not a subtype of &#39;CGFloat&#39;

It&#39;s as if, sometimes, Swift tries to &quot;cross the bridge&quot; by casting a Float to an NSNumber, which of course is the wrong thing to do when what&#39;s on the other side of the bridge expects a CGFloat. I have not yet figured out what the difference is between the two projects that causes the error to appear in one but not the other (perhaps someone else has).

**NOTE:** I may have figured out that problem: it seems to depend on the Build Active Architecture Only build setting, which in turn suggests that it&#39;s a 64-bit issue. Which makes sense, since Float would not be a match for CGFloat on a 64-bit device. That means that the impedance mismatch problem is even worse than I thought. 

### Conclusion

I&#39;m looking for practical words of wisdom on this topic. I&#39;m thinking someone may have devised some CGRect and CGPoint extension that will make life a lot easier. (Or possibly someone has written a boatload of additional arithmetic operator function overloads, such that combining CGFloat with Int or Double &quot;just works&quot; — if that&#39;s possible.)  

Swift numerics and CGFloat (CGPoint, CGRect, etc.)

I&#39;d like to create an abstract function in swift language. Is it possible?

    class BaseClass {
        func abstractFunction() {
            // How do I force this function to be overridden?
        }
    }

    class SubClass : BaseClass {
        override func abstractFunction() {
            // Override
        }
    }

Content Type	Original Author	Original Content on Stackoverflow
Question	phoganuci	View Question on Stackoverflow
Solution 1 - Swift	hfossli	View Answer on Stackoverflow
Solution 2 - Swift	nathan	View Answer on Stackoverflow
Solution 3 - Swift	Yunus T.	View Answer on Stackoverflow

Is there a way to get line number and function name in Swift language?

Swift Problem Overview

Swift Solutions

Solution 1 - Swift

Solution 2 - Swift

Solution 3 - Swift

Swift 5

Output

How to "Delete derived data" in Xcode?

How to find the highest value of a column in a data frame in R?

Attributions