How do I convert NSMutableArray to NSArray

Question

How do I convert NSMutableArray to NSArray in objective-c

User · Answer

Objective-C

Below is way to convert NSMutableArray to NSArray:

//oldArray is having NSMutableArray data-type.
//Using Init with Array method.
NSArray *newArray1 = [[NSArray alloc]initWithArray:oldArray];

//Make copy of array
NSArray *newArray2 = [oldArray copy];

//Make mutablecopy of array
NSArray *newArray3 = [oldArray mutableCopy];

//Directly stored NSMutableArray to NSArray.
NSArray *newArray4 = oldArray;

Swift

In Swift 3.0 there is new data type Array. Declare Array using let keyword then it would become NSArray And if declare using var keyword then it's become NSMutableArray.

Sample code:

let newArray = oldArray as Array

User · Answer

i was search for the answer in swift 3 and this question was showed as first result in search and i get inspired the answer from it  so here is the swift 3 code   let array   String    nsMutableArrayObject copy   as   String

User · Answer

In objective-c    NSArray  myArray    myMutableArray copy     In swift     var arr   myMutableArray as NSArray

User · Answer

An NSMutableArray is a subclass of NSArray so you won t always need to convert but if you want to make sure that the array can t be modified you can create a NSArray either of these ways depending on whether you want it autoreleased or not      Not autoreleased    NSArray  array     NSArray alloc   initWithArray mutableArray       Autoreleased array    NSArray  array    NSArray arrayWithArray mutableArray     EDIT  The solution provided by Georg Sch  lly is a better way of doing it and a lot cleaner  especially now that we have ARC and don t even have to call autorelease

User · Answer

you try this code---    NSMutableArray  myMutableArray    myArray mutableCopy     and   NSArray  myArray    myMutableArray copy

User · Answer

NSArray  array   mutableArray    This  mutableArray copy  antipattern is all over sample code  Stop doing so for throwaway mutable arrays that are transient and get deallocated at the end of the current scope   There is no way the runtime could optimize out the wasteful copying of a mutable array that is just about to go out of scope  decrefed to 0 and deallocated for good

User · Answer

If you re constructing an array via mutability and then want to return an immutable version  you can simply return the mutable array as an  NSArray  via inheritance   -  NSArray   arrayOfStrings       NSMutableArray  mutableArray    NSMutableArray array       mutableArray 0      foo       mutableArray 1      bar        return mutableArray      If you  trust  the caller to treat the  technically still mutable  return object as an immutable NSArray  this is a cheaper option than  mutableArray copy    Apple concurs      To determine whether it can change a received object  the receiver of a message must rely on the formal type of the return value  If it receives  for example  an array object typed as immutable  it should not attempt to mutate it  It is not an acceptable programming practice to determine if an object is mutable based on its class membership    The above practice is discussed in more detail here   Best Practice  Return mutableArray copy or mutableArray if return type is NSArray

User · Answer

I like both of the 2 main solutions   NSArray  array    NSArray arrayWithArray mutableArray     Or  NSArray  array    mutableArray copy     The primary difference I see in them is how they behave when mutableArray is nil   NSMutableArray  mutableArray   nil  NSArray  array    NSArray arrayWithArray mutableArray      array         empty array   NSMutableArray  mutableArray   nil  NSArray  array    mutableArray copy      array    nil

User · Answer

NSArray  array    mutableArray copy     Copy makes immutable copies  This is quite useful because Apple can make various optimizations  For example sending copy to a immutable array only retains the object and returns self   If you don t use garbage collection or ARC remember that -copy retains the object

[objective-c] How do I convert NSMutableArray to NSArray?

Objective-C

Swift

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