objective-c - 首先尝试对数组进行排序

Question

我正在尝试按照我分配给数组中每个条目的最大数字对数组进行排序。

但是我不认为它在做任何事情。关于错误可能出在哪里的任何建议？

谢谢!

 - (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];
}

Answer 1

我很好奇为什么您的排序不起作用。这样做:

#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);
    }
}

按预期将 10 20 100 打印到控制台。