How to remove an element from an array in Swift

Question

How can I unset remove an element from an array in Apple s new language Swift   Here s some code   let animals     cats    dogs    chimps    moose     How could the element animals 2  be removed from the array

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extension to remove String object  extension Array       mutating func delete element  String            self   self filter      0 as  String    element

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Swift 5  Here is a cool and easy extension to remove elements in an array  without filtering        extension Array where Element  Equatable           Remove first collection element that is equal to the given  object       mutating func remove object  Element            guard let index   firstIndex of  object  else  return          remove at  index             Usage    var myArray     cat    barbecue    pancake    frog   let objectToRemove    cat   myArray remove object  objectToRemove       barbecue    pancake    frog     Also works with other types  such as Int since Element is a generic type   var myArray    4  8  17  6  2  let objectToRemove   17  myArray remove object  objectToRemove      4  8  6  2

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Given var animals     quot cats quot    quot dogs quot    quot chimps quot    quot moose quot    Remove first element animals removeFirst       quot cats quot  print animals              quot dogs quot    quot chimps quot    quot moose quot    Remove last element animals removeLast       quot moose quot  print animals             quot cats quot    quot dogs quot    quot chimps quot    Remove element at index animals remove at  2      quot chimps quot  print animals                 quot cats quot    quot dogs quot    quot moose quot    Remove element of unknown index For only one element if let index   animals firstIndex of   quot chimps quot         animals remove at  index    print animals       quot cats quot    quot dogs quot    quot moose quot    For multiple elements var animals     quot cats quot    quot dogs quot    quot chimps quot    quot moose quot    quot chimps quot    animals   animals filter    0     quot chimps quot   print animals       quot cats quot    quot dogs quot    quot moose quot    Notes  The above methods modify the array in place  except for filter  and return the element that was removed  Swift Guide to Map Filter Reduce If you don t want to modify the original array  you can use dropFirst or dropLast to create a new array   Updated to Swift 5 2

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The above answers seem to presume that you know the index of the element that you want to delete  Often you know the reference to the object you want to delete in the array   You iterated through your array and have found it  e g   In such cases it might be easier to work directly with the object reference without also having to pass its index everywhere  Hence  I suggest this solution  It uses the identity operator      which you use to test whether two object references both refer to the same object instance  func delete element  String        list   list filter    0     element      Of course this doesn t just work for Strings

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To remove elements from an array  use the remove at     removeLast   and removeAll     yourArray    1 2 3 4    Remove the value at 2 position  yourArray remove at  2    Remove the last value from array  yourArray removeLast     Removes all members from the set  yourArray removeAll

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Few Operation relates to Array in Swift Create Array var stringArray     quot One quot    quot Two quot    quot Three quot    quot Four quot    Add Object in Array stringArray   stringArray     quot Five quot    Get Value from Index object let x   stringArray 1   Append Object stringArray append  quot At last position quot    Insert Object at Index stringArray insert  quot Going quot   at  1   Remove Object stringArray remove at  3   Concat Object value var string    quot Concate Two object of Array   stringArray 1       stringArray 2   quot

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If you have array of custom Objects  you can search by specific property like this  if let index   doctorsInArea firstIndex where    0 id    doctor id        doctorsInArea remove at  index     or if you want to search by name for example if let index   doctorsInArea firstIndex where    0 name    doctor name        doctorsInArea remove at  index

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As of Xcode 10   and according to the WWDC 2018 session 223   Embracing Algorithms   a good method going forward will be mutating func removeAll where predicate   Element  throws - gt  Bool  rethrows  Apple s example   var phrase    The rain in Spain stays mainly in the plain   let vowels  Set lt Character gt      a    e    i    o    u    phrase removeAll where    vowels contains  0        phrase     Th rn n Spn stys mnly n th pln     see Apple s Documentation  So in the OP s example  removing animals 2    chimps    var animals     cats    dogs    chimps    moose   animals removeAll where     0     chimps         or animals removeAll    0     chimps      This method may be preferred because it scales well  linear vs quadratic   is readable and clean   Keep in mind that it only works in Xcode 10   and as of writing this is in Beta

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The let keyword is for declaring constants that can t be changed  If you want to modify a variable you should use var instead  e g   var animals     cats    dogs    chimps    moose    animals remove at  2       cats    dogs    moose     A non-mutating alternative that will keep the original collection unchanged is to use filter to create a new collection without the elements you want removed  e g   let pets   animals filter    0     chimps

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Remove elements using indexes array    Array of Strings and indexes  let animals     cats    dogs    chimps    moose    squarrel    cow   let indexAnimals    0  3  4  let arrayRemainingAnimals   animals      enumerated        filter    indexAnimals contains  0 offset         map    0 element    print arrayRemainingAnimals     result -   dogs    chimps    cow    Array of Integers and indexes  var numbers    0  1  2  3  4  5  6  7  8  9  10  11  12  let indexesToRemove    3  5  8  12   numbers   numbers      enumerated        filter    indexesToRemove contains  0 offset         map    0 element    print numbers     result -  0  1  2  4  6  7  9  10  11      Remove elements using element value of another array   Arrays of integers  let arrayResult   numbers filter   element in     return  indexesToRemove contains element    print arrayResult     result -  0  1  2  4  6  7  9  10  11   Arrays of strings  let arrayLetters     a    b    c    d    e    f    g    h    i   let arrayRemoveLetters     a    e    g    h   let arrayRemainingLetters   arrayLetters filter        arrayRemoveLetters contains  0     print arrayRemainingLetters     result -   b    c    d    f    i

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You could do that  First make sure Dog really exists in the array  then remove it  Add the for statement if you believe Dog may happens more than once on your array  var animals     quot Dog quot    quot Cat quot    quot Mouse quot    quot Dog quot   let animalToRemove    quot Dog quot   for object in animals       if object    animalToRemove           animals remove at  animals firstIndex of  animalToRemove             If you are sure Dog exits in the array and happened only once just do that  animals remove at  animals firstIndex of  animalToRemove     If you have both  strings and numbers var array    12  23   quot Dog quot   78  23  let numberToRemove   23 let animalToRemove    quot Dog quot   for object in array        if object is Int              this will deal with integer  You can change to Float  Bool  etc            if object    numberToRemove           array remove at  array firstIndex of  numberToRemove                        if object is String              this will deal with strings         if object    animalToRemove           array remove at  array firstIndex of  animalToRemove

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This should do it  not tested   animals 2   3        Edit  and you need to make it a var  not a let  otherwise it s an immutable constant

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If you don t know the index of the element that you want to remove  and the element is conform the Equatable protocol  you can do  animals remove at  animals firstIndex of   quot dogs quot      See Equatable protocol answer How do I do indexOfObject or a proper containsObject

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I came up with the following extension that takes care of removing elements from an Array  assuming the elements in the Array implement Equatable  extension Array where Element  Equatable        mutating func removeEqualItems   item  Element        self   self filter    currentItem  Element  - gt  Bool in       return currentItem    item              mutating func removeFirstEqualItem   item  Element        guard var currentItem   self first else   return       var index   0     while currentItem    item         index    1       currentItem   self index            self remove at  index               Usage  var test1    1  2  1  2  test1 removeEqualItems 2      1  1   var test2    1  2  1  2  test2 removeFirstEqualItem 2      1  1  2

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For Swift4   list   list filter  0     your Value

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Regarding  Suragch s Alternative to  Remove element of unknown index     There is a more powerful version of  indexOf element   that will match on a predicate instead of the object itself   It goes by the same name but it called by myObjects indexOf  0 property   valueToMatch    It returns the index of the first matching item found in myObjects array   If the element is an object struct  you may want to remove that element based on a value of one of its properties   Eg  you have a Car class having car color property  and you want to remove the  red  car from your carsArray   if let validIndex    carsArray indexOf  0 color    UIColor redColor         carsArray removeAtIndex validIndex      Foreseeably  you could rework this to remove  all  red cars by embedding the above if statement within a repeat while loop  and attaching an else block to set a flag to  break  out of the loop

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I use this extension  almost same as Varun s  but this one  below  is all-purpose    extension Array where Element  Equatable            mutating func delete element  Iterator Element                    self   self filter  0    element

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Swift 5  guard let index   orders firstIndex of  videoID  else   return   orders remove at  index

[arrays] How to remove an element from an array in Swift

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