How to append elements into a dictionary in Swift

Question

I have a simple Dictionary which is defined like   var dict   NSDictionary     1    abc   2    cde     Now I want to add an element into this dictionary  3    efg   How can I append 3    efg  into this existing dictionary

User · Accepted Answer

You re using NSDictionary  Unless you explicitly need it to be that type for some reason  I recommend using a Swift dictionary   You can pass a Swift dictionary to any function expecting NSDictionary without any extra work  because Dictionary lt  gt  and NSDictionary seamlessly bridge to each other  The advantage of the native Swift way is that the dictionary uses generic types  so if you define it with Int as the key and String as the value  you cannot mistakenly use keys and values of different types   The compiler checks the types on your behalf    Based on what I see in your code  your dictionary uses Int as the key and String as the value  To create an instance and add an item at a later time you can use this code   var dict    1   abc   2   cde      dict is of type Dictionary lt Int  String gt  dict 3     efg    If you later need to assign it to a variable of NSDictionary type  just do an explicit cast   let nsDict   dict as  NSDictionary   And  as mentioned earlier  if you want to pass it to a function expecting NSDictionary  pass it as-is without any cast or conversion

User · Answer

As of Swift 5  the following code collection works       main dict to start with  var myDict   Dictionary     1    abc   2    cde        dict s  to be added to main dict  let myDictToMergeWith   Dictionary     5    l m n    let myDictUpdated   Dictionary     5    lmn    let myDictToBeMapped   Dictionary     6    opq     myDict 3   fgh   myDict updateValue  ijk   forKey  4    myDict merge myDictToMergeWith   current     in current   print myDict    myDict merge myDictUpdated      new  in new   print myDict    myDictToBeMapped map        myDict  0 0     0 1     print myDict

User · Answer

if you want to modify or update NSDictionary then  first of all typecast it as NSMutableDictionary  let newdictionary   NSDictionary as NSMutableDictionary   then simply use    newdictionary setValue value  AnyObject   forKey  String

User · Answer

Up till now the best way I have found to append data to a dictionary by using one of the higher order functions of Swift i e   reduce   Follow below code snippet   newDictionary   oldDictionary reduce  newDictionary     r  e in var r   r  r e 0    e 1  return r      Dharmesh In your case  it will be   newDictionary   dict reduce  3    efg      r  e in var r   r  r e 0    e 1  return r     Please let me know if you find any issues in using above syntax

User · Answer

you can add using the following way and change Dictionary to NSMutableDictionary  dict  key      value

User · Answer

If your dictionary is Int to String you can do simply   dict 3     efg    If you mean adding elements to the value of the dictionary a possible solution    var dict   Dictionary lt String  Array lt Int gt  gt     dict  key        1  dict  key    append 1  dict  key    append 1

User · Answer

I know this might be coming very late  but it may prove useful to someone  So for appending key value pairs to dictionaries in swift  you can use updateValue value    forKey    method as follows    var dict     1    abc   2    cde   dict updateValue  efg   forKey  3  print dict

User · Answer

String Any  For the fellows using  String Any  instead of Dictionary below is the extension extension Dictionary where Key    String  Value    Any            mutating func append anotherDict  String Any             for  key  value  in anotherDict               self updateValue value  forKey  key

User · Answer

SWIFT 3 - XCODE 8 1  var dictionary     Int String      dictionary updateValue value   Hola   forKey  1  dictionary updateValue value   Hello   forKey  2  dictionary updateValue value   Aloha   forKey  3    So  your dictionary contains   dictionary 1  Hola  2  Hello  3  Aloha

User · Answer

There is no function to append the data in dictionary  You just assign the value against new key in existing dictionary  it will automatically add value to the dictionary   var param      Name   Aloha   user     Aloha 2   param  questions      Are you mine   print param    The output will be like    Name   Aloha   user     Aloha 2   questions      Are you mine

User · Answer

Swift 5 happy coding  var tempDicData   NSMutableDictionary    for temp in answerList       tempDicData setValue  your value   forKey   your key

User · Answer

Given two dictionaries as below  var dic1     quot a quot   1   quot c quot   2  var dic2     quot e quot   3   quot f quot   4   Here is how you can add all the items from dic2 to dic1  dic2 forEach      dic1  0 key     0 value

User · Answer

For whoever reading this for swift 5 1        1  Using updateValue to update the given key or add new if doesn t exist       var dictionary    Int String            dictionary updateValue  egf   forKey  3         2  Using a dictionary key       var dictionary    Int String            dictionary key     value         3  Using subscript and mutating append for the value      var dictionary    Int  String          dictionary key  default    val    append  value

User · Answer

Swift 3   Example to assign new values to Dictionary  You need to declare it as NSMutableDictionary   var myDictionary  NSMutableDictionary       let newValue   1 myDictionary  newKey     newValue print myDictionary

User · Answer

In Swift  if you are using NSDictionary  you can use setValue   dict setValue  value   forKey   key

User · Answer

I added Dictionary extension  extension Dictionary        func cloneWith   dict   Key  Value   - gt   Key  Value        var result   self     dict forEach   key  value in result key    value       return result           you can use cloneWith like this   newDictionary   dict reduce  3    efg      r  e in r cloneWith e

User · Answer

var dict     name    Samira    surname    Sami      Add a new enter code herekey with a value dict  email      sample email com  print dict

User · Answer

Dict updateValue updates value for existing key from dictionary or adds new new key-value pair if key does not exists   Example-  var caseStatusParams   String  AnyObject      userId    UserDefault userID   caseStatusParams updateValue  Hello  as AnyObject  forKey   otherNotes     Result-       2 elements     - key    userId      - value   866      2 elements     - key    otherNotes      - value    Hello

User · Answer

To add new elements just set    listParrameters  your parrameter     value

[swift] How to append elements into a dictionary in Swift?

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