Re: Sorting Array Alphabetically
Re: Sorting Array Alphabetically
- Subject: Re: Sorting Array Alphabetically
- From: Ricky Sharp <email@hidden>
- Date: Fri, 13 Apr 2007 18:11:07 -0500
On Apr 13, 2007, at 3:17 PM, Deborah Goldsmith wrote:
I think the first one will work the way you want by passing
NSString's compare:
Not quite. Based on the sample data, I'm guessing this sort is
intended to be shown to an end user. compare: should *never* be
used to sort a list for display to an end user. It does a
comparison based on the Unicode code point values, which is not
what most users would consider "sorted."
Lists being sorted for end users should *always* use
localizedCompare: or localizedCaseInsensitiveCompare:. Only use
compare: if the end user will not see the ordering.
Actually, I was told to use (which I do)
compare:options:range:locale: for user-displayed items. This tends
to mimic as close as possible what Finder will do.
For example:
@implementation NSString (SortingExample)
- (NSComparisonResult)compare1:(NSString*)aString
{
return [self localizedCompare:aString];
}
- (NSComparisonResult)compare2:(NSString*)aString
{
NSDictionary* theLocaleDictionary = [[NSUserDefaults
standardUserDefaults] dictionaryRepresentation];
return [self compare:aString options:NSCaseInsensitiveSearch |
NSNumericSearch
range:NSMakeRange (0, [self length])
locale:theLocaleDictionary];
}
@end
@implementation MyController
- (void)applicationDidFinishLaunching:(NSNotification*)aNotification
{
NSMutableArray* theFirstArray =
[NSMutableArray arrayWithObjects:@"student #3", @"abc",
@"student #10", @"student #1",
@"def", @"pqr", nil];
NSMutableArray* theSecondArray = [theFirstArray mutableCopy];
[theFirstArray sortUsingSelector:@selector(compare1:)]; //
localizedCompare:
[theSecondArray sortUsingSelector:@selector(compare2:)]; //
compare:options:range:locale:
NSLog (@"localizedCompare: = %@", theFirstArray);
NSLog (@"compare:options:range:locale: = %@", theSecondArray);
}
@end
Output is...
localizedCompare: = (abc, def, pqr, "student #1", "student #10",
"student #3")
compare:options:range:locale: = (abc, def, pqr, "student #1",
"student #3", "student #10")
Note that I used ASCII7 values for the sake of this e-mail. Both
will work with Unicode and will also honor the user's localization
prefs. The main reason to not use localizedCompare, as you can see,
is when dealing with ordinal values in the strings.
___________________________________________________________
Ricky A. Sharp mailto:email@hidden
Instant Interactive(tm) http://www.instantinteractive.com
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