How do I sort an NSMutableArray with custom objects in it

Question

What I want to do seems pretty simple  but I can t find any answers on the web  I have an NSMutableArray of objects  and let s say they are  Person  objects  I want to sort the NSMutableArray by Person birthDate which is an NSDate   I think it has something to do with this method   NSArray  sortedArray    drinkDetails sortedArrayUsingSelector  selector          In Java I would make my object implement Comparable  or use Collections sort with an inline custom comparator   how on earth do you do this in Objective-C

User · Answer

Sorting NSMutableArray is very simple   NSMutableArray  arrayToFilter          NSMutableArray arrayWithObjects   Photoshop                                            Flex                                            AIR                                            Flash                                            Acrobat   nil  autorelease    NSMutableArray  productsToRemove     NSMutableArray array  autorelease    for  NSString  products in arrayToFilter        if  fliterText  amp  amp           products rangeOfString fliterText                         options NSLiteralSearch NSCaseInsensitiveSearch  length    0            productsToRemove addObject products      arrayToFilter removeObjectsInArray productsToRemove

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Use like this for nested objects   NSSortDescriptor   sortDescriptor     NSSortDescriptor alloc  initWithKey   lastRoute to lastname  ascending YES selector  selector caseInsensitiveCompare     NSMutableArray  sortedPackages     NSMutableArray alloc initWithArray  packages sortedArrayUsingDescriptors   sortDescriptor       lastRoute is one object and that object holds the to object  that to object hold the lastname string values

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If you re just sorting an array of NSNumbers  you can sort them with 1 call    arrayToSort sortUsingSelector   selector compare       That works because the objects in the array  NSNumber objects  implement the compare method  You could do the same thing for NSString objects  or even for an array of custom data objects that implement a compare method    Here s some example code using comparator blocks  It sorts an array of dictionaries where each dictionary includes a number in a key  sort key     define SORT KEY    sort key     anArray sortUsingComparator      id obj1  id obj2         NSInteger value1     obj1 objectForKey  SORT KEY  intValue     NSInteger value2     obj2 objectForKey  SORT KEY  intValue     if  value1  gt  value2       return  NSComparisonResult NSOrderedDescending         if  value1  lt  value2       return  NSComparisonResult NSOrderedAscending          return  NSComparisonResult NSOrderedSame         The code above goes through the work of getting an integer value for each sort key and comparing them  as an illustration of how to do it  Since NSNumber objects implement a compare method  it could be rewritten much more simply     define SORT KEY    sort key     anArray sortUsingComparator     id obj1  id obj2        NSNumber  key1    obj1 objectForKey  SORT KEY     NSNumber  key2    obj2 objectForKey  SORT KEY     return  key1 compare  key2          or the body of the comparator could even be distilled down to 1 line     return   obj1 objectForKey  SORT KEY  compare   obj2 objectForKey  SORT KEY      I tend to prefer simple statements and lots of temporary variables because the code is easier to read  and easier to debug  The compiler optimizes away the temporary variables anyway  so there is no advantage to the all-in-one-line version

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Your Person objects need to implement a method  say compare  which takes another Person object  and return NSComparisonResult according to the relationship between the 2 objects   Then you would call sortedArrayUsingSelector  with  selector compare   and it should be done   There are other ways  but as far as I know there is no Cocoa-equiv of the Comparable interface  Using sortedArrayUsingSelector  is probably the most painless way to do it

User · Answer

let sortedUsers   users sorted        0 firstName  lt   1 firstName

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Swift version  5 1  If you have a custom struct or class and want to sort them arbitrarily  you should call sort   using a trailing closure that sorts on a field you specify  Here s an example using an array of custom structs that sorts on a particular property       struct User           var firstName  String            var users             User firstName   Jemima            User firstName   Peter            User firstName   David            User firstName   Kelly            User firstName   Isabella              users sort            0 firstName  lt   1 firstName         If you want to return a sorted array rather than sort it in place  use sorted   like this       let sortedUsers   users sorted            0 firstName  lt   1 firstName

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There is a missing step in Georg Sch  lly s second answer  but it works fine then    NSSortDescriptor  sortDescriptor  sortDescriptor      NSSortDescriptor alloc  initWithKey   birthDate                                                ascending YES  autorelease   NSArray  sortDescriptors    NSArray arrayWithObject sortDescriptor   NSArray  sortedArray  sortedArray    drinkDetails sortedArrayUsingDescriptors sortDescriptors        added the  s  because time was wasted when I copied and pasted and it failed without the  s  in sortedArrayUsingDescriptors

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Starting in iOS 4 you can also use blocks for sorting   For this particular example I m assuming that the objects in your array have a  position  method  which returns an NSInteger   NSArray  arrayToSort   where ever you get the array from      NSComparisonResult   sortBlock  id  id      id obj1  id obj2         if   obj1 position   gt   obj2 position                   return  NSComparisonResult NSOrderedDescending            if   obj1 position   lt   obj2 position                  return  NSComparisonResult NSOrderedAscending            return  NSComparisonResult NSOrderedSame     NSArray  sorted    arrayToSort sortedArrayUsingComparator sortBlock     Note  the  sorted  array will be autoreleased

User · Answer

Sort Array In Swift    For Swifty Person below is a very clean technique to achieve above goal for globally  Lets have an example custom class of User which have some attributes   class User  NSObject       var id  String      var name  String      var email  String      var createdDate  Date      Now we have an array which we need to sort on the basis of createdDate either ascending and or descending  So lets add a function for date comparison   class User  NSObject       var id  String      var name  String      var email  String      var createdDate  Date      func checkForOrder   otherUser  User    order  ComparisonResult  - gt  Bool           if let myCreatedDate   self createdDate  let othersCreatedDate   otherUser createdDate                 This line will compare both date with the order that has been passed              return myCreatedDate compare othersCreatedDate     order                   return false           Now lets have an extension of Array for User  In simple words lets add some methods only for those Array s which only have User objects in it    extension Array where Element  User         This method only takes an order type  i e ComparisonResult orderedAscending     func sortUserByDate   order  ComparisonResult  - gt   User            let sortedArray   self sorted    user1  user2  - gt  Bool in             return user1 checkForOrder user2  order                    return sortedArray           Usage for Ascending Order  let sortedArray   someArray sortUserByDate  orderedAscending      Usage for Descending Order  let sortedArray   someArray sortUserByDate  orderedAscending      Usage for Same Order  let sortedArray   someArray sortUserByDate  orderedSame         Above method in extension will only be accessible if the Array is of type    User     Array lt User gt

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I ve used sortUsingFunction   in some of my projects   int SortPlays id a  id b  void  context        Play  p1   a      Play  p2   b      if  p1 score lt p2 score           return NSOrderedDescending      else if  p1 score gt p2 score           return NSOrderedAscending      return NSOrderedSame          validPlays sortUsingFunction SortPlays context nil

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In my case  I use  sortedArrayUsingComparator  to sort an array  Look at the below code   contactArray     NSArray arrayWithArray  contactSet allObjects   sortedArrayUsingComparator  NSComparisonResult ContactListData  obj1  ContactListData  obj2        NSString  obj1Str    NSString stringWithFormat          obj1 contactName obj1 contactSurname       NSString  obj2Str    NSString stringWithFormat          obj2 contactName obj2 contactSurname       return  obj1Str compare obj2Str         Also my object is    interface ContactListData   JsonData  property nonatomic strong  NSString   contactName   property nonatomic strong  NSString   contactSurname   property nonatomic strong  NSString   contactPhoneNumber   property nonatomic  BOOL isSelected   end

User · Answer

You can use the following generic method for your purpose  It should solve your issue     Called method - NSMutableArray  sortArrayList  NSMutableArray  arrDeviceList filterKeyName  NSString  sortKeyName ascending  BOOL isAscending      NSSortDescriptor  sorter     NSSortDescriptor alloc  initWithKey sortKeyName ascending isAscending        arrDeviceList sortUsingDescriptors  NSArray arrayWithObject sorter        return arrDeviceList       Calling method  self sortArrayList arrSomeList filterKeyName   anything like date name etc  ascending YES

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I tried all  but this worked for me  In a class I have another class named  crimeScene   and want to sort by a property of  crimeScene    This works like a charm   NSSortDescriptor  sorter     NSSortDescriptor alloc  initWithKey   crimeScene distance  ascending YES    self arrAnnotations sortUsingDescriptors  NSArray arrayWithObject sorter

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NSMutableArray  stockHoldingCompanies    NSMutableArray arrayWithObjects fortune1stock fortune2stock fortune3stock fortune4stock fortune5stock fortune6stock   nil    NSSortDescriptor  sortOrder    NSSortDescriptor sortDescriptorWithKey   companyName  ascending NO     stockHoldingCompanies sortUsingDescriptors  NSArray arrayWithObject sortOrder     NSEnumerator  enumerator    stockHoldingCompanies objectEnumerator    ForeignStockHolding  stockHoldingCompany   NSLog   Fortune 6 companies sorted by Company Name         while  stockHoldingCompany    enumerator nextObject             NSLog                                              NSLog   CompanyName     stockHoldingCompany companyName           NSLog   Purchase Share Price   2f  stockHoldingCompany purchaseSharePrice           NSLog   Current Share Price    2f  stockHoldingCompany currentSharePrice           NSLog   Number of Shares   i  stockHoldingCompany numberOfShares           NSLog   Cost in Dollars    2f   stockHoldingCompany costInDollars            NSLog   Value in Dollars     2f   stockHoldingCompany valueInDollars              NSLog

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I did this in iOS 4 using a block  Had to cast the elements of my array from id to my class type  In this case it was a class called Score with a property called points   Also you need to decide what to do if the elements of your array are not the right type  for this example I just returned NSOrderedSame  however in my code I though an exception   NSArray  sorted     scores sortedArrayUsingComparator   id obj1  id obj2       if   obj1 isKindOfClass  Score class    amp  amp   obj2 isKindOfClass  Score class              Score  s1   obj1          Score  s2   obj2           if  s1 points  gt  s2 points                return  NSComparisonResult NSOrderedAscending            else if  s1 points  lt  s2 points                return  NSComparisonResult NSOrderedDescending                          TODO  default is the same      return  NSComparisonResult NSOrderedSame       return sorted    PS  This is sorting in descending order

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Compare method  Either you implement a compare-method for your object   -  NSComparisonResult compare  Person   otherObject       return  self birthDate compare otherObject birthDate      NSArray  sortedArray    drinkDetails sortedArrayUsingSelector  selector compare       NSSortDescriptor  better   or usually even better   NSSortDescriptor  sortDescriptor  sortDescriptor     NSSortDescriptor alloc  initWithKey   birthDate                                             ascending YES   NSArray  sortedArray    drinkDetails sortedArrayUsingDescriptors   sortDescriptor      You can easily sort by multiple keys by adding more than one to the array  Using custom comparator-methods is possible as well  Have a look at the documentation   Blocks  shiny    There s also the possibility of sorting with a block since Mac OS X 10 6 and iOS 4   NSArray  sortedArray  sortedArray    drinkDetails sortedArrayUsingComparator  NSComparisonResult id a  id b        NSDate  first     Person  a birthDate       NSDate  second     Person  b birthDate       return  first compare second         Performance  The -compare  and block-based methods will be quite a bit faster  in general  than using NSSortDescriptor as the latter relies on KVC   The primary advantage of the NSSortDescriptor method is that it provides a way to define your sort order using data  rather than code  which makes it easy to e g  set things up so users can sort an NSTableView by clicking on the header row

User · Answer

You use NSSortDescriptor to sort an NSMutableArray with custom objects   NSSortDescriptor  sortingDescriptor   sortingDescriptor     NSSortDescriptor alloc  initWithKey   birthDate                                         ascending YES    NSArray  sortArray    drinkDetails sortedArrayUsingDescriptors   sortDescriptor

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You have to create sortDescriptor and then you can sort the nsmutablearray by using sortDescriptor like below    let sortDescriptor   NSSortDescriptor key   birthDate   ascending  true  selector   selector NSString compare        let array   NSMutableArray array  self aryExist sortedArray using   sortDescriptor     print array

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For NSMutableArray  use the sortUsingSelector method  It sorts it-place  without creating a new instance

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iOS 4 blocks will save you     featuresArray     unsortedFeaturesArray sortedArrayUsingComparator    id a  id b          DMSeatFeature  first     DMSeatFeature    a      DMSeatFeature  second     DMSeatFeature    b       if   first quality    second quality           return NSOrderedSame      else               if   eSeatQualityGreen     m seatQuality    eSeatQualityYellowGreen    m seatQuality    eSeatQualityDefault     m seatQuality                         if   first quality  lt  second quality                   return NSOrderedAscending              else                 return NSOrderedDescending                    else    eSeatQualityRed    eSeatQualityYellow                       if   first quality  gt  second quality                   return NSOrderedAscending              else                 return NSOrderedDescending                      retain     http   sokol8 blogspot com 2011 04 sorting-nsarray-with-blocks html a bit of description

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NSSortDescriptor  sortDescriptor  sortDescriptor      NSSortDescriptor alloc  initWithKey   birthDate  ascending YES  autorelease   NSArray  sortDescriptors    NSArray arrayWithObject sortDescriptor   NSArray  sortedArray  sortedArray    drinkDetails sortedArrayUsingDescriptors sortDescriptors     Thanks  it s working fine

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Swift s protocols and functional programming makes that very easy you just have to make your class conform to the Comparable protocol  implement the methods required by the protocol and then use the sorted by    high order function to create a sorted array without need to use mutable arrays by the way   class Person  Comparable       var birthDate  NSDate      let name  String      init name  String            self name   name            static func    lhs  Person  rhs  Person  - gt  Bool           return lhs birthDate     rhs birthDate    lhs birthDate  compare rhs birthDate as  Date      orderedSame            static func  lt  lhs  Person  rhs  Person  - gt  Bool           return lhs birthDate  compare rhs birthDate as  Date      orderedAscending            static func  gt  lhs  Person  rhs  Person  - gt  Bool           return lhs birthDate  compare rhs birthDate as  Date      orderedDescending           let p1   Person name   Sasha   p1 birthDate   NSDate     let p2   Person name   James   p2 birthDate   NSDate    he is older by miliseconds  if p1    p2       print  they are the same     they are not    let persons    p1  p2     sort the array based on who is older let sortedPersons   persons sorted by    0  gt   1      print sasha which is p1 print persons first  name    print James which is the  older  print sortedPersons first  name

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I just done multi level sorting based on custom requirement     sort the values       arrItem sortUsingComparator  NSComparisonResult  id a  id b        ItemDetail   itemA    ItemDetail  a      ItemDetail  itemB   ItemDetail  b         item price are same     if  itemA m price m selling   itemB m price m selling             NSComparisonResult result    itemA m itemName compare itemB m itemName              if item names are same  then monogramminginfo has to come before the non monograme item         if  result  NSOrderedSame                 if  itemA m monogrammingInfo                    return NSOrderedAscending               else                  return NSOrderedDescending                                  return result               asscending order     return itemA m price m selling  gt  itemB m price m selling        https   sites google com site greateindiaclub mobil-apps ios multilevelsortinginiosobjectivec

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- NSMutableArray   sortArray  NSMutableArray   toBeSorted      NSArray  sortedArray    sortedArray    toBeSorted sortedArrayUsingComparator  NSComparisonResult id a  id b           return  a compare b         return  sortedArray mutableCopy

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See the NSMutableArray method sortUsingFunction context    You will need to set up a compare function which takes two objects  of type Person  since you are comparing two Person objects  and a context parameter   The two objects are just instances of Person  The third object is a string  e g    birthDate    This function returns an NSComparisonResult  It returns NSOrderedAscending if PersonA birthDate  lt  PersonB birthDate  It will return NSOrderedDescending if PersonA birthDate   PersonB birthDate  Finally  it will return NSOrderedSame if PersonA birthDate    PersonB birthDate   This is rough pseudocode  you will need to flesh out what it means for one date to be  less    more  or  equal  to another date  such as comparing seconds-since-epoch etc     NSComparisonResult compare Person  firstPerson  Person  secondPerson  void  context      if   firstPerson birthDate   lt   secondPerson birthDate       return NSOrderedAscending    else if   firstPerson birthDate   gt   secondPerson birthDate       return NSOrderedDescending    else      return NSOrderedSame      If you want something more compact  you can use ternary operators   NSComparisonResult compare Person  firstPerson  Person  secondPerson  void  context      return   firstPerson birthDate   lt   secondPerson birthDate     NSOrderedAscending     firstPerson birthDate   gt   secondPerson birthDate     NSOrderedDescending   NSOrderedSame      Inlining could perhaps speed this up a little  if you do this a lot

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Sort using NSComparator    If we want to sort custom objects we need to provide NSComparator  which is used to compare custom objects  The block returns an NSComparisonResult value to denote the ordering of the two objects  So in order to sort whole array NSComparator is used in following way   NSArray  sortedArray    employeesArray sortedArrayUsingComparator  NSComparisonResult Employee  e1  Employee  e2       return  e1 firstname compare e2 firstname             Sorts Using NSSortDescriptor Let   s assume  as an example  that we have an array containing instances of a custom class  Employee has attributes  firstname  lastname and age  The following example illustrates how to create an NSSortDescriptor that can be used to sort the array contents in ascending order by the age key   NSSortDescriptor  ageDescriptor     NSSortDescriptor alloc  initWithKey   age  ascending YES   NSArray  sortDescriptors     ageDescriptor   NSArray  sortedArray    employeesArray sortedArrayUsingDescriptors sortDescriptors     Sort using Custom Comparisons Names are strings  and when you sort strings to present to the user you should always use a localized comparison  Often you also want to perform a case insensitive comparison  Here comes an example with  localizedStandardCompare   to order the array by last and first name   NSSortDescriptor  lastNameDescriptor     NSSortDescriptor alloc                initWithKey   lastName  ascending YES selector  selector localizedStandardCompare     NSSortDescriptor   firstNameDescriptor     NSSortDescriptor alloc                initWithKey   firstName  ascending YES selector  selector localizedStandardCompare     NSArray  sortDescriptors     lastNameDescriptor  firstNameDescriptor   NSArray  sortedArray    employeesArray sortedArrayUsingDescriptors sortDescriptors     For reference and detailed discussion please refer  https   developer apple com library ios documentation Cocoa Conceptual SortDescriptors Articles Creating html http   www ios-blog co uk tutorials objective-c how-to-sort-nsarray-with-custom-objects

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I have created a small library of category methods  called Linq to ObjectiveC  that makes this sort of thing more easy  Using the sort method with a key selector  you can sort by birthDate as follows   NSArray  sortedByBirthDate    input sort  id id person        return  person birthDate

[ios] How do I sort an NSMutableArray with custom objects in it?

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