NSArray remove item from array

Question

How to remove an item from NSArray

User · Answer

This category may be to your taste  But  Be frugal with its usage  since we are converting to a NSMutableArray and back again  it s not at all efficient    implementation NSArray  mxcl   -  NSArray   arrayByRemovingObject  id obj       if   obj  return  self copy      copy because all array  methods return new arrays     NSMutableArray  mutableArray    NSMutableArray arrayWithArray self        mutableArray removeObject obj       return  NSArray arrayWithArray mutableArray       end

User · Answer

NSArray is not mutable  that is  you cannot modify it  You should take a look at NSMutableArray  Check out the  Removing Objects  section  you ll find there many functions that allow you to remove items    anArray removeObjectAtIndex  index    anArray removeObject  item    anArray removeLastObject

User · Answer

Remove Object from NSArray with this Method   - NSArray    removeObjectFromArray  NSArray    array withIndex  NSInteger  index       NSMutableArray  modifyableArray     NSMutableArray alloc  initWithArray array        modifyableArray removeObjectAtIndex index       return   NSArray alloc  initWithArray modifyableArray

User · Answer

NSMutableArray  arrayThatYouCanRemoveObjects    NSMutableArray arrayWithArray your array     arrayThatYouCanRemoveObjects removeObjectAtIndex your object index     your array release     your array     NSArray arrayWithArray  arrayThatYouCanRemoveObjects  retain     that s about it  if you dont own your array i e it s autoreleased  remove the release  amp  retain messages

User · Answer

Made a category like mxcl  but this is slightly faster    My testing shows  15  improvement  I could be wrong  feel free to compare the two yourself     Basically I take the portion of the array thats in front of the object and the portion behind and combine them  Thus excluding the element   -  NSArray   prefix arrayByRemovingObject  id object        if   object            return self             NSUInteger indexOfObject    self indexOfObject object       NSArray  firstSubArray    self subarrayWithRange NSMakeRange 0  indexOfObject        NSArray  secondSubArray    self subarrayWithRange NSMakeRange indexOfObject   1  self count - indexOfObject - 1        NSArray  newArray    firstSubArray arrayByAddingObjectsFromArray secondSubArray        return newArray

User · Answer

As others suggested  NSMutableArray has methods to do so but sometimes you are forced to use NSArray  I d use   NSArray  newArray    oldArray subarrayWithRange NSMakeRange 1   oldArray count  - 1      This way  the oldArray stays as it was but a newArray will be created with the first item removed

User · Answer

Here s a more functional approach using Key-Value Coding    implementation NSArray  Additions   -  instancetype arrayByRemovingObject  id object       return  self filteredArrayUsingPredicate  NSPredicate predicateWithFormat   SELF         object        end

[iphone] NSArray + remove item from array

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