Searching an NSMutableArray of classes - objective-c

Question

I have my own class defined as below.
#interface PersonList : NSObject
#property(nonatomic, strong)NSNumber *ID;
#property(nonatomic, strong)NSString *FirstName;
#property(nonatomic, strong)NSString *SecondName;
#end
I use it like the following method:
PersonList *P = [[PersonList alloc]init];
[P setID: ...];
[P setFirstname:...];
[P setSecondname:...];
then add it to an array.
[PersonListArray addObject:P];
What I'm trying to do is search this array for the class where ID = x.
Is it the best way?
for(int i = 0; i < PersonListArray.count; i++)
{
PersonListArray *aPersonListArray = [PersonListArray objectAtIndex:i];
if(aPersonListArray.ID == x)
{
//Do what i want here
//break;
}
}
Thanks

Answer 1

You can use this NSArray method that makes things a lot easier and is also very optimized:
- (NSUInteger)indexOfObjectPassingTest:(BOOL (^)(id obj, NSUInteger idx, BOOL *stop))predicate
Your code should then look like that:
NSInteger personIndex = [PersonListArray indexOfObjectPassingTest:^BOOL(PersonList person, NSUInteger idx, BOOL *stop) {
return [person.ID isEqualToNumber:x];
}];
PersonList personList = PersonListArray[personIndex]
Two more things:
you might consider not capitalizing your variables, to follow conventions.
If you want to compare values of objects in ObjC, use the equalTo methods, not the == sign which is for comparing pointers
Hope this helps,

Answer 2

There is another way, a little bit more simple:
for(PersonList *AnyPerson in PersonListArray)
{
if([AnyPerson.ID isEqualToNumber:x])
{
//do what you want
}
}

Answer 3

You could do this like this:
for(PersonList *person in PersonListArray){
if([person.ID isEqualToNumber: x]){
// do your job, it you want to do it for the first case only
// use break here or return depends on the case
}
}
Take a look at the way of comparing values (if you want sth more than equality consider usage of compare: method)
BTW It might be valuable for you to take a look on the possibilities of sorting and searching arrays in case of possibilities and performance, take a look at this.

Answer 4

Try this
#interface PersonList ()
#property (nonatomic, strong) NSMutableArray *persons;
#end
#implementation PersonList
-(NSMutableArray *)persons{
static dispatch_once_t onceToken;
dispatch_once(&onceToken,^{
_persons=[[NSMutableArray alloc] init];
});
return _persons;
}
-(instancetype)initWithIDs:(NSArray *)personIDs FirstNames:(NSArray *)firstNames SecondNames:(NSArray *)secondNames{
if(self=[super init]){
[personIDs enumerateObjectsUsingBlock:^(id personID, NSUInteger idx, BOOL *stop) {
NSMutableDictionary *person=[[NSMutableDictionary alloc] init];
[person setObject:personID forKey:#"ID"];
[person setObject:[firstNames objectAtIndex:idx] forKey:#"FIRSTNAME"];
[person setObject:[secondNames objectAtIndex:idx] forKey:#"SECONDNAME"];
[self.persons addObject:person];
}];
}
return self;
}
-(NSDictionary *)findPersonByID:(NSString *)personID{
__block NSDictionary *dictionary=[[NSDictionary alloc] init];
[self.persons enumerateObjectsUsingBlock:^(id person, NSUInteger idx, BOOL *stop) {
if ([[person objectForKey:#"ID"] isEqualToString:personID]) {
dictionary=person;
*stop=YES;
}
}];
return dictionary;
}
#end