Re: Sort Array
Re: Sort Array
- Subject: Re: Sort Array
- From: Ondra Cada <email@hidden>
- Date: Sat, 16 Nov 2002 13:36:53 +0100
On Friday, November 15, 2002, at 06:11 , Lorenzo Puleo wrote:
I have a short list with "Name" and "Surname" fields.
I want to sort this list by "Surname".
How should I build the NSArray?
How should I use the NSArray methods?
Another 101, looks like ;)
An array of dictionaries seems to be the best solution, something like
(typed into message, typos and bugs possible):
NSString * const Name=@"Name", * const Surname=@"Surname";
NSMutableArray *list=nil; // in practice would be rather some controller's
property than a global
// just like these functions would be rather some controller's methods
void addPersonWithNameAndSurname(NSString *name,NSString *surname) {
if (!list) list=[[NSMutableArray alloc] init];
[list addObject:[NSDictionary/*or perhaps NSMutableDictionary --
depends on usage*/
dictionaryWithObjectsAndKeys:name,Name,surname,Surname,nil]];
}
NSString *nameOfPersonAtIndex(int i) {
return [[list objectAtIndex:i] objectForKey:Name];
}
static int compareDictBySurname(id left,id right,void *ctxt) {
// cast needed to get rid of a warning, since compare: is improperly
declared in headers
return [(NSString*)[left objectForKey:Surname] compare:[right
objectForKey:Surname]];
}
void sortPersonsBySurname {
[list sortUsingFunction:compareDictBySurname context:NULL];
}
Of course it all depends mainly on the usage: another possibility would be
to store names as values into a dictionary keyed by surnames... The above
solution though would be probably the most generic one.
---
Ondra Cada
OCSoftware: email@hidden
http://www.ocs.cz
private email@hidden
http://www.ocs.cz/oc
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| References: | |
| | >Sort Array (From: Lorenzo Puleo <email@hidden>) |