Question

This is my simplified NSMutableArray from a JSON parsing:

{
main 
{ 
  array0, 
  array1,
  array2,
  array3,    <----- remove!
  array4,    <----- remove!
  array5,
  array6,    <----- remove!
  array7,    <----- remove!
  array8,
  ...,
}
}

Im looking the best way to REMOVE SINGLE array items ALTERNATIVELY, example only arrays 2,4,6,8; Also, if I need to remove COUPLES of array 3,4 and 6,7, always alternatively?

EDIT: this is the first solution, to remove SINGLE items alternatively:

for (int i=0; i < [array count]; i = i+1) {
[array removeObjectAtIndex:i];
}

Answer 1

To me it sounds like you could easily create an index set of all the indexes to remove and remove the objects at those indexes using removeObjectsAtIndexes:.

You can get the indexes of all the even (or odd) indexed objects from indexesOfObjectsPassingTest:.

NSMutableArray *array = // Your array where objects should be removed from
NSIndexSet *indexesToRemove = [array indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
    return idx%2==0; // index is even (even objects get removed)
}];
[array removeObjectsAtIndexes:indexesToRemove];