String comparison for localization
cocoa, cocoa-touch, ios, nsstring, objective-c
Solution
`localizedCaseInsensitiveCompare:` is equivalent to:
[aString compare:otherString
options:NSCaseInsensitiveSearch
range:NSMakeRange(0,aString.length)
locale:[NSLocale currentLocale]];
`localizedStandardCompare:` is basically equivalent to:
[aString compare:otherString
options:NSCaseInsensitiveSearch | NSNumericSearch
range:NSMakeRange(0,aString.length)
locale:[NSLocale currentLocale]];
So, the primary difference is in how numbers within strings are compared.
Comparing the following 3 strings using `localizedCaseInsensitiveCompare:` would result in the following order:
"Foo2.txt",
"Foo25.txt",
"Foo7.txt"
On the other hand, comparing them using `localizedStandardCompare:` would result in the following order:
"Foo2.txt",
"Foo7.txt",
"Foo25.txt"
While the `localizedCaseInsensitiveCompare:` method has been around forever, the `localizedStandardCompare:` was only added recently (OS X 10.6). The Finder sorts filenames using the numeric method, and prior to the addition of `localizedStandardCompare:`, developers were without an easy way to assure they could sort strings like the Finder did.
When determining which one to use, if the strings you're comparing represent filenames, then you should definitely tend toward using `localizedStandardCompare:`.
Problem
What is the difference between `NSString`'s `localizedCaseInsensitiveCompare:` and `localizedStandardCompare:` methods? I read the reference but did not get a proper idea of which one to use.