I\'ve got an array of objects, and I need them sorted by their \"title\" key. It\'s currently working, though it\'s using an ASCII sort instead of a natural sort. The titles are filenames, so they look like this:
file1
file2
file3
...
file10
file11
file12
I\'m getting, as you would expect:
file1
file10
file11
file12
file2
file3
...
Does anyone know if there is a way built-in to the NSArray sorting functionality to get this natural sorting as opposed to the alphabetical sort? I found some generic algorithms, but I was hoping for something built-in...
NSString
s can be compared using the NSNumericSearch compare option.
One version:
NSInteger sort(Obj* a, Obj* b, void*) {
return [[a title] compare:[b title] options:NSNumericSearch];
}
result = [array sortedArrayUsingFunction:&sort context:nil];
Or a bit more generic:
NSInteger sort(id a, id b, void* p) {
return [[a valueForKey:(NSString*)p]
compare:[b valueForKey:(NSString*)p]
options:NSNumericSearch];
}
result = [array sortedArrayUsingFunction:&sort context:@\"title\"]
Or using blocks:
result = [array sortedArrayUsingComparator:^(Obj* a, Obj* b) {
return [[a title] compare:[b title] options:NSNumericSearch];
}];
Those attempting to replicate the Finder\'s sorting behavior on Mac OS X 10.6 and later and iOS 4 and later can use localizedStandardCompare:
as the comparator selector.
Those with the same goal on earlier versions of Mac OS X and/or iOS should use the solution described in the String Programming Guide.
Based on @PeterHosey\'s answer, if you\'re working with an array of string objects:
SHORT ANSWER:
NSArray *orderedTitles = [unorderedTitles sortedArrayUsingSelector:@selector(localizedStandardCompare:)];
FULL EXAMPLE:
NSArray *unorderedTitles = @[
@\"file12\",
@\"file1\",
@\"file10\",
@\"file3\",
@\"file2\",
@\"file11\"
];
NSArray *orderedTitles = [unorderedTitles sortedArrayUsingSelector:@selector(localizedStandardCompare:)];
NSLog(@\"orderedTitles = %@\", orderedTitles);
/*
orderedTitles = (
file1,
file2,
file3,
file10,
file11,
file12
)
*/
This works on iOS
NSString *name0 = @\"winter\";
NSString *name1 = @\"summer\";
CFComparisonResult result = CFStringCompareWithOptions(
(CFStringRef) name0,
(CFStringRef) name1,
CFRangeMake (0, CFStringGetLength((CFStringRef) name0)),
kCFCompareCaseInsensitive | kCFCompareLocalized | kCFCompareNumerically
);
You can also do the sorting in the following way:
NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@\"title\" ascending:YES selector:@selector(localizedStandardCompare:)];
NSArray *sortedItems = [unsortedItems sortedArrayUsingDescriptors:@[sortDescriptor]];