iOS - 基础集合类

iOS基础集合类

NSArray

排序

- (NSEnumerator<ObjectType> *)objectEnumerator;
- (NSEnumerator<ObjectType> *)reverseObjectEnumerator;
- (NSArray<ObjectType> *)sortedArrayUsingFunction:(NSInteger (NS_NOESCAPE *)(ObjectType, ObjectType, void * _Nullable))comparator context:(nullable void *)context;
- (NSArray<ObjectType> *)sortedArrayUsingFunction:(NSInteger (NS_NOESCAPE *)(ObjectType, ObjectType, void * _Nullable))comparator context:(nullable void *)context hint:(nullable NSData *)hint;
- (NSArray<ObjectType> *)sortedArrayUsingSelector:(SEL)comparator;
- (NSArray<ObjectType> *)subarrayWithRange:(NSRange)range;

1. 逆序

/// 将原有的数组逆序输出
[[array reverseObjectEnumerator] allObjects];

 - (void)testArraySort {
     NSArray *array1 = @[@1,@123,@98,@6,@77,@22];
     NSArray *result = [[array1 reverseObjectEnumerator] allObjects];
     NSLog(@"%@",result);
}

输出：

2018-05-11 10:32:21.820441+0800 XWArrayDictionaryDemo[2148:94679] (
    22,
    77,
    6,
    98,
    123,
    1
)

2. 升序 、降序

升序

/// 升序
- (void)testNumberSort {
    NSArray *array = @[@1,@123,@98,@6,@77,@22];
    NSArray *result = [array sortedArrayUsingSelector:@selector(compare:)];
    NSLog(@"%@",result);
}

输出：

2018-05-11 13:52:31.889127+0800 XWArrayDictionaryDemo[5877:230244] (
    1,
    6,
    22,
    77,
    98,
    123
)

/// 升序
- (void)testNumberSort2 {
    NSArray *array = @[@1,@9,@6,@2,@7,@4];
    NSArray *result = [array sortedArrayUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
        return [obj1 compare:obj2];
    }];
    NSLog(@"%@",result);
}

输出：

2018-05-11 13:58:59.779001+0800 XWArrayDictionaryDemo[6065:252727] (
    1,
    2,
    4,
    6,
    7,
    9
)

降序

/// 降序
- (void)testSort3 {
    NSArray *array = @[@1,@9,@6,@2,@7,@4];
    NSArray *result = [[[array sortedArrayUsingSelector:@selector(compare:)] reverseObjectEnumerator] allObjects];
    NSLog(@"%@",result);
}

输出：

2018-05-11 14:01:36.237543+0800 XWArrayDictionaryDemo[6140:260610] (
    9,
    7,
    6,
    4,
    2,
    1
)

/// 降序
- (void)testSort4 {
    NSArray *array = @[@1,@9,@6,@2,@7,@4];
    NSArray *result = [array sortedArrayUsingComparator:^NSComparisonResult(id  _Nonnull obj1, id  _Nonnull obj2) {
        return [obj2 compare:obj1];
    }];
    NSLog(@"%@",result);
}

输出：

2018-05-11 14:02:41.385379+0800 XWArrayDictionaryDemo[6182:265228] (
    9,
    7,
    6,
    4,
    2,
    1
)

枚举

使用 indexesOfObjectsWithOptions:passingTest:

- (void)testEnum {
    NSArray *array = @[@"邱学伟",@"极客学伟",@"一米八",@"CSDN",@"iOS开发"];
    [array indexesOfObjectsWithOptions:NSEnumerationConcurrent passingTest:^BOOL(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        NSLog(@"%@",obj);
        return YES;
    }];
}

For 循环

- (void)testEnum1 {
     NSArray *array = @[@"邱学伟",@"极客学伟",@"一米八",@"CSDN",@"iOS开发"];
    for (NSString *str in array) {
        NSLog(@"%@",str);
    }
}

Block 方式枚举

- (void)testEnum1 {
     NSArray *array = @[@"邱学伟",@"极客学伟",@"一米八",@"CSDN",@"iOS开发"];
    [array enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
         NSLog(@"%@",obj);
    }];
}

通过下标 index

- (void)testEnum2 {
    NSArray *array = @[@"邱学伟",@"极客学伟",@"一米八",@"CSDN",@"iOS开发"];
    for (int i = 0 ; i < array.count; i++) {
        NSLog(@"%@",array[i]);
    }
}

使用 NSEnumerator

- (void)testEnum3 {
    NSArray *array = @[@"邱学伟",@"极客学伟",@"一米八",@"CSDN",@"iOS开发"];
    NSEnumerator *enumerator = [array objectEnumerator];
    id obj;
    while (obj = [enumerator nextObject]) {
        NSLog(@"%@",obj);
    }
}

使用 predicate

- (void)testEnum4 {
    NSArray *array = @[@"邱学伟",@"极客学伟",@"一米八",@"CSDN",@"iOS开发"];\
    [array filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(id  _Nullable evaluatedObject, NSDictionary<NSString *,id> * _Nullable bindings) {
        NSLog(@"%@",evaluatedObject);
        return YES;
    }]];
}

枚举方法 / 时间 [ms]	10.000.000 elements	10.000 elements
indexesOfObjects:, concurrent	1844.73	2.25
NSFastEnumeration (for in)	3223.45	3.21
indexesOfObjects:	4221.23	3.36
enumerateObjectsUsingBlock:	5459.43	5.43
objectAtIndex:	5282.67	5.53
NSEnumerator	5566.92	5.75
filteredArrayUsingPredicate:	6466.95	6.31

NSDictionary

同样数目的值，NSDictionary比NSArray要花费多得多的内存空间

排序

通过 value 的顺序将 key 按指定顺序输出

- (NSArray *)keysSortedByValueUsingSelector:(SEL)comparator;
- (NSArray *)keysSortedByValueUsingComparator:(NSComparator)cmptr;
- (NSArray *)keysSortedByValueWithOptions:(NSSortOptions)opts
     usingComparator:(NSComparator)cmptr;

枚举

keysOfEntriesWithOptions:passingTest： 可并行

- (void)testDictEnum {
    NSDictionary *dict = @{@"邱学伟":@"3",@"极客学伟":@"1",@"一米八":@"2"};
    [dict keysOfEntriesWithOptions:NSEnumerationConcurrent passingTest:^BOOL(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
        NSLog(@"key : %@,  value : %@",key,obj);
        return YES;
    }];
}

block 枚举

- (void)testDictEnum2 {
    NSDictionary *dict = @{@"邱学伟":@"3",@"极客学伟":@"1",@"一米八":@"2"};
    [dict enumerateKeysAndObjectsUsingBlock:^(id  _Nonnull key, id  _Nonnull obj, BOOL * _Nonnull stop) {
        NSLog(@"key : %@,  value : %@",key,obj);
    }];
}

• 各个方法枚举时间参考

枚举方法 / 时间 [ms]	50.000 elements	1.000.000 elements
keysOfEntriesWithOptions:, concurrent	16.65	425.24
getObjects:andKeys:	30.33	798.49
keysOfEntriesWithOptions:	30.59	856.93
enumerateKeysAndObjectsUsingBlock:	36.33	882.93
NSFastEnumeration	41.20	1043.42
NSEnumeration	42.21	1113.08