Question

I have an NSMutableArray with 70 objects, they are NSMutableDictionary, inside each dictionary I have 2 values: “distance” and “indexPath”. I want to sort the NSMutableArray from the small distance to the biggest. The distance is in KM and the array looks like this after using the code that I pasted here:

NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:@"distance" ascending:YES];
[branchDistance sortedArrayUsingDescriptors:[NSArray arrayWithObjects:descriptor,nil]];

This is the result of this method:

(lldb) po [branchDistance objectAtIndex:0]
(id) $1 = 0x0d6ac240 {
    "<NSIndexPath 0xd6cf180> 1 indexes [0]" = indexPath;
    "8.078547" = distance;
}
(lldb) po [branchDistance objectAtIndex:1]
(id) $2 = 0x0d6a64a0 {
    "<NSIndexPath 0xd6cf3b0> 1 indexes [1]" = indexPath;
    "45.044069" = distance;
}
(lldb) po [bran(lldb) po [branchDistance objectAtIndex:2]
(id) $4 = 0x0d6cf550 {
    "<NSIndexPath 0xd69b3f0> 1 indexes [2]" = indexPath;
    "9.992081" = distance;
}
(lldb) po [branchDistance objectAtIndex:3]
(id) $5 = 0x0d6cf750 {
    "283.356727" = distance;
    "<NSIndexPath 0xd6cf480> 1 indexes [3]" = indexPath;
}

I want to sort the NSMutableArray from the small number to the big number, using this “distance” key value inside the NSMutableDictionary. I tried few pieces of code from the web and from stackoverflow, but couldn’t find something that worked for me.

Please help me!

Thanks!

Answer 1

I assume the distance values are stored in the dictionaries using an NSNumber object:

NSArray *sortedArray = [branchDistance sortedArrayUsingComparator:^(id obj1, id obj2) {
    NSNumber *distance1 = [(NSDictionary *)obj1 objectForKey:@"distance"];
    NSNumber *distance2 = [(NSDictionary *)obj2 objectForKey:@"distance"];
    return [distance1 compare:distance2];
}];