Sort NSArray of NSDictionaries using comparator - ios

Question

I've been trying to sort an NSArray of NSDictionaries using a comparator, but I cannot seem to get the output I desire.
The output I'm trying to achieve is that A-Z usernames should come first in the sorted array, then usernames that start with a digit should come second in the sorted array, and lastly usernames that start with an underscore should be last in the sorted array. Any help is truly appreciated!
EDIT: It should be sorted so it looks consistent through the whole NSArray so that: _Anna comes before _Bob and _11Bob comes before _12Cary but after _09Bob
Example of desired output I'm looking for:
(
{
username = abcd;
},
{
username = Anna;
},
{
username = 01Bob;
},
{
username = 02Tob;
},
{
username = 03ZED;
},
{
username = 04_Hob;
},
{
username = 04_sob;
},
{
username = "_anna";
},
{
username = "_bob";
},
{
username = "_boc";
},
{
username = "_bocd12";
},
{
username = "_bocd13";
}
{
username = _01Bob;
},
{
username = _02Tob;
},
)
I hope that makes sense now.
Sample NSDictionary with an NSArray of NSDictionaries:
NSDictionary *dictionary = #{#"users":#[#{#"username":#"191anna"},#{#"username":#"_091bob"},#{#"username":#"Bob"},#{#"username":#"charlie"}]};
I'm trying by using this comparator:
NSArray *array = [[dictionary objectForKey:#"users"] sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2)
{
NSString *f1 = [obj1 objectForKey:#"username"];
NSString *f2 = [obj2 objectForKey:#"username"];
NSString *s1 = [[obj1 objectForKey:#"username"]substringFromIndex:1];
NSString *s2 = [[obj2 objectForKey:#"username"]substringFromIndex:1];
if ([s1 rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]].location == [s2 rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]].location)
{
return [f1 localizedCaseInsensitiveCompare:f2];
}
else if ([s1 rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]].location != [s2 rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]].location)
{
return [f1 localizedCaseInsensitiveCompare:f2];
if ([s1 rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]].location == NSNotFound)
{
return NSOrderedDescending;
}
}
return NSOrderedAscending;
}];
But it gives me the following (not the way I want) sorted NSArray:
(
{
username = "_091bob";
},
{
username = 191anna;
},
{
username = Bob;
},
{
username = charlie;
}
)

Answer 1

Here's what I came up with. It's a touch long because it requires quite a bit of logic. It can likely be optimized further:
My Set Up:
NSArray * usernames = #[#"191anna", #"abcd", #"Anna", #"01Bob", #"02Tob", #"03ZED", #"04_rob", #"_anna", #"_bob", #"_boc", #"_bocd12", #"_bocd13", #"_01Bob", #"_02Tob"];
NSMutableArray * users = [NSMutableArray array];
for (NSString * username in usernames) {
[users addObject:#{#"username":username}];
}
NSDictionary * dictionary = #{#"users":users};
And The Sort:
NSArray *sortedArray = [dictionary[#"users"] sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2)
{
NSString *nameOne = obj1[#"username"];
NSString *nameTwo = obj2[#"username"];
NSString *startOne;
NSString *startTwo;
NSInteger currentIndex = 0;
NSInteger maxIndex = (nameOne.length < nameTwo.length) ? nameOne.length : nameTwo.length;
// Get our first differentiating letter
do {
if (currentIndex < maxIndex) {
startOne = [nameOne substringWithRange:NSMakeRange(currentIndex, 1)];
startTwo = [nameTwo substringWithRange:NSMakeRange(currentIndex, 1)];
currentIndex++;
}
else {
// Names are equal up to max length. Same length is same, else shorter word ascending. (bob above bobb)
if (nameOne.length == nameTwo.length) {
return NSOrderedSame;
}
else {
return (nameOne.length < nameTwo.length) ? NSOrderedAscending : NSOrderedDescending;
}
}
} while ([startOne isEqualToString:startTwo]);
// Prioritize underscores to bottom
NSCharacterSet * underscoreCharSet = [NSCharacterSet characterSetWithCharactersInString:#"_"];
NSRange underscoreRangeOne = [startOne rangeOfCharacterFromSet:underscoreCharSet];
NSRange underscoreRangeTwo = [startTwo rangeOfCharacterFromSet:underscoreCharSet];
if (underscoreRangeOne.length > 0 || underscoreRangeTwo.length > 0) {
// Something is underscored, put it on the bottom
return (underscoreRangeOne.length > 0) ? NSOrderedDescending : NSOrderedAscending;
}
// Prioritize numbers to bottom
NSRange decimalRangeOne = [startOne rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]];
NSRange decimalRangeTwo = [startTwo rangeOfCharacterFromSet:[NSCharacterSet decimalDigitCharacterSet]];
if (decimalRangeOne.length > 0 || decimalRangeTwo.length > 0) {
// Something is numbered, put it on the bottom
if (decimalRangeOne.length == decimalRangeTwo.length) {
return (startOne.intValue > startTwo.intValue) ? NSOrderedDescending : NSOrderedAscending;
}
else if (decimalRangeOne.length > decimalRangeTwo.length) {
return NSOrderedDescending;
}
else if (decimalRangeTwo.length > decimalRangeOne.length) {
return NSOrderedAscending;
}
}
// Now, sort alphabetically
return [nameOne localizedCaseInsensitiveCompare:nameTwo];
}];
NSLog(#"SortedArray: %#", sortedArray);
Will log as:
abcd,
Anna,
01Bob,
02Tob,
03ZED,
"04_rob",
191anna,
"_anna",
"_bob",
"_boc",
"_bocd12",
"_bocd13",
"_01Bob",
"_02Tob"

Answer 2

You can optimize this further, but your sort logic would be like below.
NSArray *sorted = [array sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
NSString *name1 = [(NSDictionary *) obj1 objectForKey:NAME];
NSString *name2 = [(NSDictionary *) obj2 objectForKey:NAME];
if ([name1 characterAtIndex:0] == '_' && [name2 characterAtIndex:0] == '_')
{
return [name1 compare:name2 options:NSCaseInsensitiveSearch];
}
else if ([name1 characterAtIndex:0] == '_')
{
return NSOrderedDescending;
}
else if ([name2 characterAtIndex:0] == '_')
{
return NSOrderedAscending;
}
else if (([name1 intValue] && [name2 intValue]) || ([name1 characterAtIndex:0] == '0' && [name2 characterAtIndex:0] == '0'))
{
return [name1 compare:name2 options:NSCaseInsensitiveSearch];
}
else if ([name1 intValue] >0 || [name1 characterAtIndex:0] == '0')
{
return NSOrderedDescending;
}
else if ([name2 intValue]>0 || [name2 characterAtIndex:0] == '0')
{
return NSOrderedAscending;
}
else
{
return [name1 compare:name2 options:NSCaseInsensitiveSearch];
}
//return res;
}];