Creating an empty NSArray

Question

in C I can simply declare an array like this:

int array[500];

to declare an array of size 500 which can then be filled later. Is it possibel to do the same thing in NSArray? I understand for the NSMutableArray there is the arrayWithCapacity class method to "create" and empty array (or at least declare the array to be filled later). Is there a way to do something similar for NSArray, since I know the exact size of my array I want to fill in the contents later in a "for" loop.

Thanks

Sergey Kalinichenko · Accepted Answer · 2014-02-24 03:04:22Z

2

Technically, int array[500]; does not create an empty array - it creates an array full of zeros. Since NSArrays is immutable, you do need to use NSMutableArray if you'd like to be able to populate it later.

You can make an array with a specific capacity, and then put objects into it, like this:

NSMutableArray *array = [NSMutableArray arrayWithCapacity:500];
for (int i = 0 ; i != 500 ; i++) {
     [array addObject:@(i)];
}

Since NSMutableArray is an NSArray, you can create it in a method as NSMutableArray*, and then return it as NSArray* to the callers.

edited Feb 24, 2014 at 3:04

answered May 16, 2012 at 16:30

Sergey Kalinichenko

729k85 gold badges1.2k silver badges1.6k bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Dave Peck Over a year ago

This answer has an issue. As stated in the documentation for [NSArray arrayWithObjects:count:]: "count is the number of values from the objects C array to include in the new array. This number will be the count of the new array. It must not be negative or greater than the number of elements in objects."

Sergey Kalinichenko Over a year ago

@DavePeck OMG, I cannot believe nobody has noticed this before! Thanks for the comment!

Collectives™ on Stack Overflow

Creating an empty NSArray

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related