进击的Objective-C--------------字典 集合

NSDictionary

1.初始化

NSDictionary *dict1 =  [[NSDictionary alloc]initWithObjectsAndKeys:@“a”,@“1”,@“b”,@“2”,@“c”,@“3”,nil];

2.初始化方法2

NSDictionary *dict2 = [NSDictionary dictionaryWithObjectsAndKeys:@“a”,@“1”,@“b”,@“2”,@“c”,@“3”,nil];

3.通过字典赋值字典

NSDictionary *dict3 = [NSDictionary dictionaryWithDictionary:dict1];

4.通过数组赋值字典

NSArray  *valueArr = [NSArray arrayWithObjects:@"a",@"b",@"c", nil];

NSArray *keyArr = [NSArray arrayWithObjects:@"1",@"2",@"3", nil];

NSDictionary *dict4 = [NSDictionary dictionaryWithObjects:valueArr forKeys:keyArr];

5.字面量

NSDictionary *dict5 = @{@“a”:@“1”,@“b”:@“2”,@“c”:@“3"};

6.通过key获得value

NSDictionary *dict = @{@“1”:@“周杰伦”,@“2”:@“庾澄庆”,@“3”:@“那英”,@“4”:@“汪峰”};

NSLog(@“%@“,[dict objectForKey:@“1”]);

7.获得所有key

NSLog(@“%@”,[dict allkey]):

8.获得所有value

NSLog(@“%@“,[dict allvalue]);

9.获得键值对个数

NSLog(@“%lu”,[dict count]);

NSMutableDictionary(可变字典)

1.赋值

NSMutableDictionary *mDict1 = [NSMutableDictionary dictionaryWithObjectsAndKey:@“a”,@“1”,@“b”,@“2”,@“c”,@“3”,nil];

2.添加

[mDict1 setObject@“d” forKey:@“4”];

3.修改

[mDict1 setObject:@“e” forKey:@“1"];

4.删除

[mDict1 removeObjectForKey:@“1”];

[mDict1 removeAllObjects];

NSArray *keyarr = [NSArray arrayWithObjects:@“4”,@“3”,nil];

[mDict1 removeObjectsForKeys:keyarr]

5.查找

NSLog(@“%@“,[mDict1 objectForKey:@“2”]);

6.遍历

1⃣️一个一个

for (int i = 0; i < [[mDict1 allValues]count]; i++) {
        NSArray *temp = [mDict1 allValues];
        NSLog(@"%@",temp);
    }

    NSArray * tempArr = [mDict1 allKeys];

2⃣️通过所有的key打印所有的value

for (int i  = 0; i < [tempArr count]; i++) {

        NSLog(@"%@",[mDict1 objectForKey:tempArr[i]]);}

NSSet(集合)

1.初始化

NSSet *set1 = [[NSSet alloc]initWithObjects:@“a”,@“b”,@“c”,nil];

2.初始化2

NSSet *set2 = [NSSet setWithObjects:@“a”,@“b”,@“c”,nil];

3.通过集合赋值集合

NSSet *set3 = [NSSet setWithSet:set2];

4.通过数组赋值集合

NSArray *setArr = [NSArray arrayWithObjects:@“a”,@“b”,@“c”,nil

];

NSSet *set = [NSSet setWithArray:setArr];

5.个数

NSLog(@“%lu”,[set2 count]);

6.判断

NSLog(@“%d”,[set1 containsObject:@“b”]);

7.查找

NSLog(@“%@“,[set1 anyObject]);

NSLog(@“%@“,[set1 allObjects]);

NSMutableSet(可变集合)

1.初始化

NSMutableSet *ms1 = [NSMutableSet setWithObjects:@“a”,@“b”,@“c”,nil];

2.增加对象

[ms1 addObject:@“d”];

3.删除对象

[ms1 removeObject:@“d"];

[ms1 removeAllObjects];

4.修改方法

[ms1 setSet:set1];

[ms1 addObject:@“a”];

NSCountedSet(NSMutableSet的子类)

1.赋值

NSCountedSet *ctSet1 = [NSCountedSet setWithObjects:@“a”,@“b”,@“c”,nil];

2.增加

[ctSet1 addObject:@“d”];

[ctSet1 addObject:@“b”];

3.个数(NSUIntager)

NSLog(@“%lu”,[ctSet1 count]);

4.统计重复元素的个数

NSLog(@“%lu”,[ctSet1 countForObject:@“a"]);

快速枚举遍历

1快速遍历一个数组

NSArray *ar = [NSArray arrayWithObjects:@“a”,@“b”,@“c”,nil];

for(NSString *    s in  ar)

{ NSLog(@“%@“,s);}

2快速遍历一个字典(遍历出来的都是key)

NSDictionary *dict11 = [NSdictionary dictionaryWithObjectsAndKeys:@“a”,@“1”,@“b”,@“2”,@“c”,@“3”,nil];

for(NSString *ss in dict11)

{ NSLog(@“%@“,ss);}

快速枚举的特点

 1数组枚举得到数组中的元素对象

 2字典枚举得到的是字典中的key值

 3集合枚举得到的是集合中的元素对象

例子:

  NSMutableArray *mArr1 = [NSMutableArray arrayWithObjects:@"daa",@"bbb",@"ccc", nil];
    for (int i = 0; i < [mArr1 count] - 1; i++) {
        for (int j = 0; j < [mArr1 count] - 1 - i; j++) {
            if ([[mArr1 objectAtIndex:j]compare:[mArr1 objectAtIndex:j + 1]] == -1) {
                [mArr1 exchangeObjectAtIndex:j withObjectAtIndex:j+1];
            }

        }

数组排序

#import "Person.h"

@implementation Person
- (NSString *)name{
    return _name;
}
- (void)setName:(NSString *)name{
    _name = name;
}
- (NSInteger)age{
    return _age;
}
- (void)setAge:(NSInteger)age{
    _age = age;
}
- (instancetype)initWithName:(NSString *)name age:(NSInteger)age{
    if (self = [super init]) {
        _name = name;
        _age = age;
    }
    return self;
}
- (NSComparisonResult)compareByName:(Person *)aPerson{
    if ([self.name compare:aPerson.name] == 1) {
        return NSOrderedDescending;
    }else if ([self.name compare:aPerson.name] == 0){
        return NSOrderedSame;
    }
    else
        return NSOrderedAscending;
 
}
// 格式化字符串 有一个description方法 它可以用于打印数组
- (NSString *)description{
    NSString *s = [NSString stringWithFormat:@"name:%@,age:%ld",self.name,self.age];
    return s;
}
- (NSComparisonResult)compareByAge:(Person *)aPerson{
    if (self.age > aPerson.age) {
        return NSOrderedDescending;
    }else if (self.age == aPerson.age){
        return NSOrderedSame;
    }
    else
        return NSOrderedAscending;
}

@end

#import "Person.h"
int main(int argc, const char * argv[]) {
    // 有三个人 分别叫 "kobe" 18 "james" 15 "durant" 20按照姓名和年龄进行排序
   
    Person * p1 = [[Person alloc]initWithName:@"kobe" age:18];
    Person * p2 = [[Person alloc]initWithName:@"james" age:15];
    Person * p3 = [[Person alloc]initWithName:@"durant" age:20];
    NSMutableArray *ms1 = [NSMutableArray arrayWithObjects:p1,p2,p3, nil];
    // @selector是一个关键字 指的是一个方法选择器 里面可以写方法名去实现方法
    [ms1 sortUsingSelector:@selector(compareByAge:)];
   
    NSLog(@"%@",ms1);
    [ms1 sortUsingSelector:@selector(compareByName:)];

    NSLog(@"%@",ms1);