CODEWITHSUNDEEP
iosobjective-c
Rendy
Rendy

Reputation: 5698

How to get capacity of NSMutableArray?

I have following code:

[[NSMutableArray alloc] initWithCapacity:slidingValue]

However, if I try to get the size of it by using count directly after above initialisation, it will return 0. There is no adding object into it yet though.

Am I able to get the capacity of it?

Upvotes: 1

Views: 691

Answers (1)

TheHungryCub
TheHungryCub

Reputation: 1960

You don't need the capacity. It's an optimization, and depending on how large a capacity you specify and what internal algorithm NSArray chooses, might actually be ignored. Just add the objects when you get them, using -addObject: or -insertObject:. Different from a CFArray, the capacity of an NSArray isn't a hard limit. It's just a suggestion.

If you get your objects in a random order (but with an index number), you could create an array and fill it with [NSNull null] objects using -addObject:, then replace the NSNull with the actual object as you get it. But the latter is rarely needed.

Note:

The -initWithCapacity: method creates an empty array with a hint of how large the array can reach before a memory reallocation. The count increases when you actually -addObject: to the array.

Upvotes: 1

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