how to remove duplicate value in NSMutableArray

Question

i'm scanning wifi info using NSMutableArray, but there are few duplicate values appear, so i try to use following code but still getting the duplicate values,

if([scan_networks count] > 0) 
{
    NSArray *uniqueNetwork = [[NSMutableArray alloc] initWithArray:[[NSSet setWithArray:scan_networks] allObjects]];
    [scan_networks removeAllObjects];

    NSSortDescriptor *networkName = [[[NSSortDescriptor alloc] initWithKey:@"SSID_STR" ascending:YES] autorelease];
    NSArray *descriptors = [NSArray arrayWithObjects:networkName,nil];

    [scan_networks addObjectsFromArray:[uniqueNetwork sortedArrayUsingDescriptors:descriptors]];
}

how this can be resolve, thanks

score 4 · Answer 1 · edited May 23 '17 at 11:53

4

You should be using an NSMutableSet in the first place.

For eliminating all double entries in an array, see this question:
Make NSMutableArray or NSMutableSet unique.

edited May 23 '17 at 11:53

Community

1
1

answered Dec 07 '09 at 08:45

Georg Schölly

124,188
49
220
267

i have try with NSMutableSet, but still can't remove, – Apache Dec 07 '09 at 10:16
`NSSet` requires that your objects implement `-hash` and `-isEqual:`, have you done this? – Georg Schölly Dec 07 '09 at 11:53

score 4 · Accepted Answer · edited Dec 02 '11 at 19:32

You can use NSSET but if you it is only used when order doesn't matter if order matter then go for this approach.I have used it and it give perfect answer. in Place of NSmutableArray array put your NSmutableArray which contains duplicate Value.

NSArray *copy = [NSmutableArray copy];

NSInteger index = [copy count] - 1;

for (id object in [copy reverseObjectEnumerator])
 {

 if ([NSmutableArray indexOfObject:object inRange:NSMakeRange(0, index)] != NSNotFound)

 {
        [NSmutableArray removeObjectAtIndex:index];

 }

    index--;
}

[copy release];

score 3 · Answer 3 · edited May 16 '12 at 05:34

Here is the code of removing duplicates values from NSMutable Array..it will work for you. myArray is your Mutable Array that you want to remove duplicates values..

for(int j = 0; j < [myArray count]; j++){
    for( k = j+1;k < [myArray count];k++){
        NSString *str1 = [myArray objectAtIndex:j];
        NSString *str2 = [myArray objectAtIndex:k];
        if([str1 isEqualToString:str2])
            [myArray removeObjectAtIndex:k];
       }
}
// Now print your array and

score 1 · Answer 4 · edited Dec 03 '13 at 09:21

I think its better to do this:

 NSMutableIndexSet *indexes = [[NSMutableIndexSet alloc]init];

 for(int j = 0; j < [myArray count]; j++) {

 for( k = j+1;k < [myArray count];k++) {

    NSString *str1 = [myArray objectAtIndex:j];
    NSString *str2 = [myArray objectAtIndex:k];
    if([str1 isEqualToString:str2])
        [indexes addIndex:k];
   }
}

[myArray removeObjectsAtIndexes:indexes];

You can run into problems if you manipulate the array while looping in my experience.

score 1 · Answer 5 · answered Mar 30 '15 at 16:00

1

This is another way:

- (NSArray *)removeDuplicatesFrom:(NSArray *)array {
    NSSet *set = [NSSet setWithArray:array];
    return [set allObjects];
}

answered Mar 30 '15 at 16:00

julien

437
4
9

score 0 · Answer 6 · answered Aug 06 '13 at 16:26

maybe you can try the NSArray category.

#import <Foundation/Foundation.h>

@interface NSArray(filterRepeat)
-(NSArray *)filterRepeat;

@end


#import "NSArray+repeat.h"
@implementation NSArray(filterRepeat)
-(NSArray *)filterRepeat
{
    NSMutableArray * resultArray =[NSMutableArray array];
    [self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        if (![resultArray containsObject: obj]) {
            [resultArray addObject: obj];
        }
    }];
    return resultArray;
}
@end

how to remove duplicate value in NSMutableArray

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