First try at sorting an array

Question

I am trying to sort an array by the highest number that I assigned to each entry in the array.

However i don't think it's doing anything. Any suggestions on where the error may be?

Thanks!

 - (NSArray*)sortByPercentage:(NSArray*)array {

    NSArray *inputArray = array;
    NSSortDescriptor *sortDescriptor = [[ NSSortDescriptor alloc] initWithKey:@"percentMatched" ascending:YES];

    //nov 8
    NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];
    NSArray *finalResult = [inputArray sortedArrayUsingDescriptors:sortDescriptors];
    [sortDescriptor release];
    return [NSArray arrayWithArray:finalResult];
}

it isnt... it calculates a percentage and assigns it to the entry. I am trying to filter from highest to lowest percentage. — William Falcon
– William Falcon, Commented Nov 17, 2012 at 0:51
also how would i only include entries that had a 20% or more? — William Falcon
– William Falcon, Commented Nov 17, 2012 at 1:01
There is nothing wrong with this method, it's doing the job.Probably the mistake you do is at calling it, or the key is not valid. — Ramy Al Zuhouri
– Ramy Al Zuhouri, Commented Nov 17, 2012 at 1:50

FluffulousChimp · Accepted Answer · 2012-11-17 11:20:58Z

1

I'm intrigued by why your sort doesn't work. This does:

#import <Foundation/Foundation.h>

@interface FooObject : NSObject
@property (nonatomic, assign) NSInteger value;
@property (readonly) NSInteger percentMatched;
@end

@implementation FooObject
@synthesize value;

//  compute percentMatched as an elementary function of value
- (NSInteger)percentMatched {
    return value * 2;
}
@end

int main(int argc, char *argv[]) {
    NSAutoreleasePool *p = [[NSAutoreleasePool alloc] init];

    FooObject *foo1 = [[FooObject alloc] init];
    foo1.value = 50;

    FooObject *foo2 = [[FooObject alloc] init];
    foo2.value = 5;

    FooObject *foo3 = [[FooObject alloc] init];
    foo3.value = 10;

    NSArray *myFoos = [NSArray arrayWithObjects:foo1,foo2,foo3,nil];
    NSArray *sorters = [NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"percentMatched" ascending:YES]];
    NSArray *mySortedFoos = [myFoos sortedArrayUsingDescriptors:sorters];
    for(FooObject *foo in mySortedFoos ) {
        printf("%ld ",foo.percentMatched);
    }
}

Prints 10 20 100 to the console as expected.

answered Nov 17, 2012 at 11:20

FluffulousChimp

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1 Comment

William Falcon Over a year ago

you were right... it works well, other methods were having the problem. It was surprisingly fast!

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