How to insert an array into an existing NSMutableArray at a specific index

Question

I've tried using

NSMutableArray *existingArray = [@[@"1", @"3", @"4"] mutableCopy];
NSArray *newItems = @[@"2", @"2", @"2", @"2"];
[existingArray insertObjects:newItems atIndexes:[NSIndexSet indexSetWithIndex:1]];

Above code ends up crashing because i'm suppose to provide all indexes for all new items.

What i want is to be able to insert newItems at position 1 of existingArray preserving the order of newItems in final array too.

Is there an easy way to provide all those indexes?

kirander · Accepted Answer · 2020-04-15 14:03:07Z

2

Correct answer without comments...

NSInteger position = 1;
NSRange range = NSMakeRange(position, newItems.count);
NSIndexSet *indexSet = [NSIndexSet indexSetWithIndexesInRange:range];
[existingArray insertObjects:newItems atIndexes:indexSet];

edited Apr 15, 2020 at 14:03

answered Apr 15, 2020 at 13:28

kirander

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2 Comments

Zeeshan Tufail Over a year ago

this will just add new items on top of the array. You should change the first value of NSMakeRange from 0 to 1 following the example in question.

kirander Over a year ago

@ZeeshanTufail thanks for remark. The answer was edited.

Ken Thomases · Accepted Answer · 2020-04-15 13:57:30Z

1

You can insert by "replacing" an empty range:

[existingArray replaceObjectsInRange:NSMakeRange(1, 0) withObjectsFromArray:newItems];

answered Apr 15, 2020 at 13:57

Ken Thomases

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