How do I print the type or class of a variable in Swift

Question

Is there a way to print the runtime type of a variable in swift  For example   var now   NSDate   var soon   now dateByAddingTimeInterval 5 0   println    now dynamicType        Prints   Metatype    println    now dynamicType description        Prints    NSDate  since objective-c Class objects have a  description  selector  println    soon dynamicType description        Compile-time error since ImplicitlyUnwrappedOptional lt NSDate gt  has no  description  method   In the example above  I m looking for a way to show that the variable  soon  is of type ImplicitlyUnwrappedOptional lt NSDate gt   or at least NSDate

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In the latest XCode 6 3 with Swift 1 2  this is the only way I found   if view classForCoder description       UISegment

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Xcode 7 3 1  Swift 2 2   String instanceToPrint self  componentsSeparatedByString      last

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Xcode 8 Swift 3 0 use type of    let className      type of  instance

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I had luck with   let className   NSStringFromClass obj dynamicType

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SWIFT 5  With the latest release of Swift 3 we can get pretty descriptions of type names through the String initializer  Like  for example print String describing  type of  object     Where object can be an instance variable like array  a dictionary  an Int  a NSDate  an instance of a custom class  etc   Here is my complete answer  Get class name of object as string in Swift  That question is looking for a way to getting the class name of an object as string but  also i proposed another way to getting the class name of a variable that isn t subclass of NSObject  Here it is    class Utility      class func classNameAsString obj  Any  - gt  String             prints more readable results for dictionaries  arrays  Int  etc         return String describing  type of  obj             I made a static function which takes as parameter an object of type Any and returns its class name as String       I tested this function with some variables like        let diccionary   String  CGFloat            let array   Int           let numInt   9     let numFloat  CGFloat   3 0     let numDouble  Double   1 0     let classOne   ClassOne       let classTwo  ClassTwo    ClassTwo       let now   NSDate       let lbl   UILabel     and the output was    diccionary is of type Dictionary array is of type Array numInt is of type Int numFloat is of type CGFloat numDouble is of type Double classOne is of type  ClassOne classTwo is of type  ClassTwo now is of type  Date lbl is of type  UILabel

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I found this solution which hopefully might work for someone else  I created a class method to access the value  Please bear in mind this will work for NSObject subclass only  But at least is a clean and tidy solution   class var className  String       let classString   String   NSStringFromClass self classForCoder        return classString componentsSeparatedByString      last

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Please have a look at the below code snippet and let me know if you are looking for something like below or not   var now   NSDate   var soon   now addingTimeInterval 5 0   var nowDataType   Mirror reflecting  now  print  Now is of type    nowDataType subjectType     var soonDataType   Mirror reflecting  soon  print  Soon is of type    soonDataType subjectType

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There appears to be no generic way to print the type name of an arbitrary value s type  As others have noted  for class instances you can print value className but for primitive values it appears that at runtime  the type information is gone    For instance  it looks as if there s not a way to type  1 something   and get out Int for any value of something   You can  as another answer suggested  use i bridgeToObjectiveC   className to give you a hint  but   NSCFNumber is not actually the type of i -- just what it will be converted to when it crosses the boundary of an Objective-C function call    I would be happy to be proven wrong  but it looks like the type checking is all done at compile time  and like C    with RTTI disabled  much of the type information is gone at runtime

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Is this what you re looking for   println    object getClassName now        It prints    NSDate   UPDATE  Please note this no longer seems to work as of Beta05

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Based on the answers and comments given by Klass and Kevin Ballard above  I would go with   println  stdlib getDemangledTypeName now  componentsSeparatedByString      last   println  stdlib getDemangledTypeName soon  componentsSeparatedByString      last   println  stdlib getDemangledTypeName soon   componentsSeparatedByString      last   println  stdlib getDemangledTypeName soon   componentsSeparatedByString      last    println  stdlib getDemangledTypeName myvar0  componentsSeparatedByString      last   println  stdlib getDemangledTypeName myvar1  componentsSeparatedByString      last   println  stdlib getDemangledTypeName myvar2  componentsSeparatedByString      last   println  stdlib getDemangledTypeName myvar3  componentsSeparatedByString      last     which will print out    NSDate   ImplicitlyUnwrappedOptional   Optional   NSDate    NSString   PureSwiftClass   Int   Double

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I ve found a solution for self-developed classes  or such you have access to    Place the following computed property within your objects class definition   var className  String        return   FILE   lastPathComponent stringByDeletingPathExtension     Now you can simply call the class name on your object like so   myObject className   Please note that this will only work if your class definition is made within a file that is named exactly like the class you want the name of   As this is commonly the case the above answer should do it for most cases  But in some special cases you might need to figure out a different solution     If you need the class name within the class  file  itself you can simply use this line   let className     FILE   lastPathComponent stringByDeletingPathExtension     Maybe this method helps some people out there

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Update September 2016  Swift 3 0  Use type of    e g  type of  someThing   since the dynamicType keyword has been removed   Update October 2015   I updated the examples below to the new Swift 2 0 syntax  e g  println was replaced with print  toString   is now String      From the Xcode 6 3 release notes    nschum points out in the comments that the Xcode 6 3 release notes show another way      Type values now print as the full demangled type name when used with   println or string interpolation    import Foundation  class PureSwiftClass      var myvar0   NSString      Objective-C class var myvar1   PureSwiftClass   var myvar2   42 var myvar3    Hans   print   String myvar0 dynamicType  - gt    myvar0 dynamicType    print   String myvar1 dynamicType  - gt    myvar1 dynamicType    print   String myvar2 dynamicType  - gt    myvar2 dynamicType    print   String myvar3 dynamicType  - gt    myvar3 dynamicType     print   String Int self            - gt    Int self    print   String  Int   self         - gt     Int   self    print   String NSString self       - gt    NSString self    print   String Array lt String gt  self  - gt    Array lt String gt  self      Which outputs   String myvar0 dynamicType  - gt    NSCFConstantString String myvar1 dynamicType  - gt  PureSwiftClass String myvar2 dynamicType  - gt  Int String myvar3 dynamicType  - gt  String String Int self            - gt  Int String  Int   self         - gt  Optional lt Int gt  String NSString self       - gt  NSString String Array lt String gt  self  - gt  Array lt String gt    Update for Xcode 6 3   You can use the  stdlib getDemangledTypeName     print   TypeName0      stdlib getDemangledTypeName myvar0     print   TypeName1      stdlib getDemangledTypeName myvar1     print   TypeName2      stdlib getDemangledTypeName myvar2     print   TypeName3      stdlib getDemangledTypeName myvar3       and get this as output   TypeName0   NSString TypeName1     lldb expr 26 PureSwiftClass TypeName2   Swift Int TypeName3   Swift String   Original answer   Prior to Xcode 6 3  stdlib getTypeName got the mangled type name of a variable  Ewan Swick s blog entry helps to decipher these strings    e g   TtSi stands for Swift s internal Int type   Mike Ash has a great blog entry covering the same topic

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Swift 4       TypeName  func stringType of some  Any  - gt  String       let string    some is Any Type    String describing  some    String describing  type of  some       return string        ModuleName TypeName  func fullStringType of some  Any  - gt  String       let string    some is Any Type    String reflecting  some    String reflecting  type of  some       return string     Usage   print stringType of  SomeClass             SomeClass  print stringType of  SomeClass self        SomeClass  print stringType of  String                String  print fullStringType of  String            Swift String

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As of Xcode 6 3 with Swift 1 2  you can simply convert type values into the full demangled String   toString Int                        Swift Int  toString Int Type                   Swift Int Type  toString  10  dynamicType           Swift Int  println Bool self                   Swift Bool  println  UTF8  self                 Swift Array lt Swift UTF8 gt   println  Int  String  self           Swift Int  Swift String   println  String     dynamicType     Swift Optional lt Swift String gt   println NSDate                      NSDate  println NSDate Type                 NSDate Type  println WKWebView                   WKWebView  toString MyClass                     Module Name  MyClass  toString MyClass   dynamicType       Module Name  MyClass

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The top answer doesn t have a working example of the new way of doing this using type of   So to help rookies like me  here is a working example  taken mostly from Apple s docs here - https   developer apple com documentation swift 2885064-type  doubleNum   30 1  func printInfo   value  Any        let varType   type of  value      print     value   of type    varType        printInfo doubleNum     30 1  of type  Double

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Swift version 4   print    type of  self       function       within a function of a class   Thanks  Joshua Dance

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Swift 3 0  let string    Hello  let stringArray     one    two   let dictionary     key   2   print type of  string       String      Get type name as a string String describing  type of  string       String  String describing  type of  stringArray       Array lt String gt   String describing  type of  dictionary       Dictionary lt String  Int gt       Get full type as a string String reflecting  type of  string       Swift String  String reflecting  type of  stringArray       Swift Array lt Swift String gt   String reflecting  type of  dictionary       Swift Dictionary lt Swift String  Swift Int gt

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Many of the answers here do not work with the latest Swift  Xcode 7 1 1 at time of writing    The current way of getting the information is to create a Mirror and interrogate that  For the classname it is as simple as   let mirror   Mirror reflecting  instanceToInspect  let classname String   mirror description   Additional information about the object can also be retrieved from the Mirror  See http   swiftdoc org v2 1 type Mirror  for details

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You can still access the class  through className  which returns a String    There are actually several ways to get the class  for example classForArchiver  classForCoder  classForKeyedArchiver  all return AnyClass     You can t get the type of a primitive  a primitive is not a class    Example   var ivar       ivar className      NSDictionaryI  var i   1 i className    error   Int  does not have a member named  className    If you want to get the type of a primitive  you have to use bridgeToObjectiveC    Example   var i   1 i bridgeToObjectiveC   className      NSCFNumber

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I ve tried some of the other answers here but milage seems to very on what the underling object is   However I did found a way you can get the Object-C class name for an object by doing the following   now  superclass as AnyObject    replace now with the object you are trying to get the class name for   Here is and example of how you would use it   let now   NSDate   println  what is this     now  superclass as AnyObject       In this case it will print NSDate in the console

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My current Xcode is Version 6 0  6A280e    import Foundation  class Person   var name  String  init name  String    self name   name    class Patient  Person    class Doctor  Person     var variables  Any          5      7 5      true       maple       Person name  Sarah        Patient name  Pat        Doctor name  Sandy      for variable in variables       let typeLongName    stdlib getDemangledTypeName variable      let tokens   split typeLongName     0               if let typeName   tokens last           println  Variable   variable  is of Type   typeName               Output   Variable 5 is of Type Int  Variable 7 5 is of Type Double  Variable true is of Type Bool  Variable maple is of Type String  Variable Swift001 Person is of Type Person  Variable Swift001 Patient is of Type Patient  Variable Swift001 Doctor is of Type Doctor

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This is how you get a type string of your object or Type which is consistent and takes into account to which module the object definition belongs to or nested in  Works in Swift 4 x    inline   always  func typeString for  type  Any Type  - gt  String       return String reflecting  type of   type       inline   always  func typeString for object  Any  - gt  String       return String reflecting  type of  type of  object       struct Lol       struct Kek          if you run this in playground the results will be something like typeString for  Lol self             lldb expr 74 Lol Type typeString for  Lol                  lldb expr 74 Lol Type typeString for  Lol Kek self         lldb expr 74 Lol Kek Type typeString for  Lol Kek              lldb expr 74 Lol Kek Type

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To get a type of object or class of object in Swift  you must need to use a type of  yourObject    type of  yourObject

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When using Cocoa  not CocoaTouch   you can use the className property for objects that are subclasses of NSObject    println now className    This property is not available for normal Swift objects  which aren t subclasses of NSObject  and in fact  there is no root id or object type in Swift    class Person       var name  String     var p   Person   println person className      lt - Compiler error   In CocoaTouch  at this time there is not a way to get a string description of the type of a given variable  Similar functionality also does not exist for primitive types in either Cocoa or CocoaTouch   The Swift REPL is able to print out a summary of values including its type  so it is possible this manner of introspection will be possible via an API in the future   EDIT  dump object  seems to do the trick

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You can use reflect to get information about object  For example name of object class    var classname   reflect now  summary

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In lldb as of beta 5  you can see the class of an object with the command   fr v -d r shipDate   which outputs something like    DBSalesOrderShipDate DBSalesOrderShipDate     shipDate   0x7f859940   The command expanded out means something like   Frame Variable  print a frame variable  -d run target  expand dynamic types   Something useful to know is that using  Frame Variable  to output variable values guarantees no code is executed

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This is also handy when checking if an object is a type of a class   if someObject is SomeClass         someObject is a type of SomeClass

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Another important aspect that influences the class name returned from String describing  type of  self   is Access Control   Consider the following example  based on Swift 3 1 1  Xcode 8 3 3  July 2017   func printClassNames          let className1   SystemCall lt String gt    getClassName       print className1     prints   SystemCall lt String gt        let className2   DemoSystemCall   getClassName       print className2     prints   DemoSystemCall          private class example     let className3   PrivateDemoSystemCall   getClassName       print className3     prints    PrivateDemoSystemCall in  0FC31E1D2F85930208C245DE32035247            fileprivate class example     let className4   FileprivateDemoSystemCall   getClassName       print className4     prints    FileprivateDemoSystemCall in  0FC31E1D2F85930208C245DE32035247       class SystemCall lt T gt        func getClassName   - gt  String           return String describing  type of  self            class DemoSystemCall  SystemCall lt String gt       private class PrivateDemoSystemCall  SystemCall lt String gt       fileprivate class FileprivateDemoSystemCall  SystemCall lt String gt        As you can see  all classes in this example have different levels of access control which influence their String representation  In case the classes have private or fileprivate access control levels  Swift seems to append some kind of identifier related to the  nesting  class of the class in question   The result for both PrivateDemoSystemCall and FileprivateDemoSystemCall is that the same identifier is appended because they both are nested in the same parent class   I have not yet found a way to get rid of that  other than some hacky replace or regex function   Just my 2 cents

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let i  Int   20     func getTypeName v  Any  - gt  String       let fullName    stdlib demangleName  stdlib getTypeName i       if let range   fullName rangeOfString                return fullName substringFromIndex range endIndex            return fullName    println  Var type is   getTypeName i       i

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In Xcode 8  Swift 3 0 Steps  1  Get the Type  Option 1  let type   Type   MyClass self    Determines Type from Class  Option 2  let type   Type   type of self    Determines Type from self  2  Convert Type to String  let string   String    quot   type  quot    String

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Not exactly what you are after  but you can also check the type of the variable against Swift types like so   let object  AnyObject   1  if object is Int     else if object is String       For example

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Edit  A new toString function has been introduced in Swift 1 2  Xcode 6 3    You can now print the demangled type of any type using  self and any instance using  dynamicType   struct Box lt T gt      toString  foo  dynamicType                Swift String toString  1  23  456  dynamicType         Swift Array lt Swift Int gt  toString  7 as NSNumber  dynamicType        NSCFNumber  toString  Bool   self                     Swift Optional lt Swift Bool gt  toString Box lt SinkOf lt Character gt  gt  self        lldb expr 1 Box lt Swift SinkOf lt Swift Character gt  gt  toString NSStream self                    NSStream     Try calling YourClass self and yourObject dynamicType   Reference  https   devforums apple com thread 227425

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Swift 3 0  Xcode 8  With the following code you can ask an instance for its class  You can also compare two instances  wether having the same class      CREATE pure SWIFT class class MySwiftClass       var someString   String    default      var someInt      Int   5       CREATE instances let firstInstance   MySwiftClass   let secondInstance   MySwiftClass   secondInstance someString    Donald  secondInstance someInt   24     INSPECT instances if type of  firstInstance      MySwiftClass self       print  SUCCESS with         else       print  PROBLEM with          if type of  firstInstance     MySwiftClass self       print  SUCCESS with        else       print  PROBLEM with            COMPARE CLASS OF TWO INSTANCES if type of  firstInstance      type of  secondInstance        print  instances have equal class     else       print  instances have NOT equal class

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In Swift 3 0  you can use type of    as dynamicType keyword has been removed

[swift] How do I print the type or class of a variable in Swift?

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