ObjectiveC-NSMutable array specific indexes stored in another array

Question

Is there anyway I can add specific objects in NSMutableArray to another array in objective c? I can accomplish that in Java but cannot figure it our for objective c

For example I have an array of 7 strings and I only want indexes 1, 3 ,7 stored in another array.

To be clear; you want the array index stored in this other array, not the string objects? — Droppy
– Droppy, Commented Jul 1, 2015 at 14:53

Droppy · Accepted Answer · 2015-07-01 14:57:34Z

1

Here is one way of creating the array from the string values at particular indexes:

NSMutableArray *array = ...;    // Array with strings
NSArray *someOtherArray = @[ array[1], array[3], array[7] ];

So both array[1] and someOtherArray[0] point to the same (NSString) instance, etc.

edited Jul 1, 2015 at 14:57

answered Jul 1, 2015 at 14:54

Droppy

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1 Comment

DevMe Over a year ago

THANKS that helped..will accept the answer in 2 min :D

KirkSpaziani · Accepted Answer · 2015-07-01 17:11:33Z

0

This is what NSIndexSet (and NSMutableIndexSet) is for.

You can build it manually or use helper methods on NSArray like:

indexesOfObjectsPassingTest:

to build an index set from a block. You can then enumerate over the NSIndexSet using a for loop - using the index to call into the original array.

answered Jul 1, 2015 at 17:11

KirkSpaziani

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