CODEWITHSUNDEEP
iosobjective-ccocoansarrayenumeration
hungry
hungry

Reputation: 174

NSArray enumerating by group

Using Objective-C, is it possible to go through an array by groups : exemple :

NSArray *arr = 1, 2, 3, ....100;

Every 10 objects, do something and go on

so :

object 0 to 9 : you do something with each object and after the 10° object you do a last action

then object 10 to 19 : you do something with each object and after the 19° object you do a last action

and so on until the last object

thank you for your help

Upvotes: 0

Views: 120

Answers (3)

rintaro
rintaro

Reputation: 51911

"enumerating by group"; If you want exactly as stated, you can subclass NSEnumerator.

For example:

In your Application code:

#import "NSArray+SubarrayEnumerator.h"

NSArray *arr = ...;

for(NSArray *grp in [arr subarrayEnumeratorEach:10]) {
   // do what you want.
}

NSArray+SubarrayEnumerator.h

#import <Foundation/Foundation.h>

@interface NSArray (SubarrayEnumerator)
- (NSEnumerator *)subarrayEnumeratorEach:(NSUInteger)perPage;
@end

NSArray+SubarrayEnumerator.m

#import "NSArray+SubarrayEnumerator.h"

@interface _NSArraySubarrayEnumeratorEach : NSEnumerator
@property (assign, nonatomic) NSUInteger cursor;
@property (assign, nonatomic) NSUInteger perPage;
@property (strong, nonatomic) NSArray *src;
@end

@implementation NSArray (SubarrayEnumerator)
- (NSEnumerator *)subarrayEnumeratorEach:(NSUInteger)perPage {
    _NSArraySubarrayEnumeratorEach *enumerator = [[_NSArraySubarrayEnumeratorEach alloc] init];
    enumerator.perPage = perPage;
    enumerator.src = self;
    return enumerator;
}
@end

@implementation _NSArraySubarrayEnumeratorEach

- (id)nextObject {
    NSUInteger start = _cursor;
    if(start >= _src.count) {
        return nil;
    }
    NSUInteger count = MIN(_perPage, _src.count - start);
    _cursor += _perPage;
    return [_src subarrayWithRange:NSMakeRange(start, count)];
}

@end

Upvotes: 1

Prasad
Prasad

Reputation: 6034

No it is not possible in Objective-C with in-built functions which matches your exact description. There are crude ways to do it by loops which matches your exact description.

But if you are aware before hand that you are going to make such type of operations, define your own data-structure. Create an NSObject sub-class, define your items (10 items which you were talking about) in it. Then in array, you can directly take out each instance of it comprising of your defined NSObject.

Upvotes: 1

Andrey Chernukha
Andrey Chernukha

Reputation: 21808

something like this:

 for (int i = 0; i < arr.count; i++)
{
    [self doSomethingWithArray];

    if (i % 10 == 0)
        [self doSomethingElse];
}

Upvotes: 1

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