iphone - 根据另一个数组中的对象从数组中删除特定对象

Question

设置：有一个UITableView显示美国高尔夫球场的名称、街道、州等。 UITableView's数据源是NSMutableArray我班级中的一个对象，GolfCourse名为allGolfCourses.

现在我想删除所有西海岸高尔夫球场allGolfCourses并创建一个新的array名为eastCoastGolfCourses. 我有另一个NSArray与string objects所有西海岸州（缩写）有关，westCoastStates但很难将这两者联系起来。

如何遍历 allGolfCourses 并删除在 westCoastStates数组中找到状态缩写的所有对象？

westCoastStates 数组：

self.westCoastStates = [NSMutableArray arrayWithObjects:
                        @"CH",
                        @"OR",
                        @"WA",
                        nil];

高尔夫球场.h

@interface GolfCourse : NSObject

@property (nonatomic, strong) NSString *longitude;
@property (nonatomic, strong) NSString *latitude;
@property (nonatomic, strong) NSString *clubName;
@property (nonatomic, strong) NSString *state;
@property (nonatomic, strong) NSString *courseInfo;
@property (nonatomic, strong) NSString *street;
@property (nonatomic, strong) NSString *city;
@property (nonatomic, strong) NSString *clubID;
@property (nonatomic, strong) NSString *phone;

@end

注意：NSString *state; 包含州缩写，例如：FL

我知道如何使用单个参数来执行此操作，但不知道如何检查westCoastStates数组中的所有字符串。希望你能帮忙。

Answer 1

怎么样？

NSSet* westCoastStatesSet = [NSSet setWithArray:self.westCoastStates];
NSIndexSet* eastCoastGolfCoursesIndexSet = [allGolfCourses indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
    GolfCourse* course = (GolfCourse*)obj;
    if ([westCoastStatesSet containsObject:course.state]) {
        return NO;
    }
    return YES;
}];

NSArray* eastCoastGolfCourses = [allGolfCourses objectsAtIndexes:eastCoastGolfCoursesIndexSet];

更新：我相信这可以通过使用谓词来浓缩

NSPredicate *inPredicate = [NSPredicate predicateWithFormat: @"!(state IN %@)", self.westCoastStates];
NSArray* eastCoastGolfCourses = [allGolfCourses filteredArrayUsingPredicate:inPredicate];

Answer 2

伪代码：

for (int i = 0; i < allGolfCourses.length;) {
    Course* course = [allGolfCourses objectAtIndex:i];
    if (<is course in one of the "bad" states?>) {
       [allGolfCourse removeObjectAtIndex:i];
    }
    else {
        i++;
    }
}

Answer 3

您可以像这样快速迭代数组：

[self.allGolfCourses enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {

    GolfCourse *currentGolfCourse = (GolfCourse *)obj;
    if(![self.westCoastStates containsObject:currentGolfCourse.state]){
        [self.eastCoastStates addObject:currentGolfCourse];
    }
}];