使用字典，能很好的组织数据，OC中的字典有三种方式

//创建字典
NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys:@"value",@"key",@"github",@"build", nil];
NSDictionary *dic1 = @{@"key1":@"value1"};
NSDictionary *dic2 = [NSDictionary dictionaryWithObjectsAndKeys:@"value2",@"key2", nil];

包含多少个键值对

//包含多少个键值对
NSLog(@"%zd",dic.count);

通过已知的key名来获取值

//已知key来获取值
NSString *value = [dic objectForKey:@"key"];
NSLog(@"%@",value);

获取所有的key和获取所有的值

//获取所有的key名或者值，返回一个不可变数组
NSArray *keys = [dic allKeys];
NSArray *values = [dic allValues];
NSLog(@"%@",keys);
NSLog(@"%@",values);

通过一个数组key获取值

NSArray *vals = [dic objectsForKeys:@[@"key"] notFoundMarker:@"not"];
NSLog(@"%@",vals);

遍历

[dic enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
    NSLog(@"%@",key);
    NSLog(@"%@",obj);
}];

排序

NSArray *kesArray =  [dic keysSortedByValueUsingComparator:^NSComparisonResult(id obj1, id obj2) {
    NSString *ke1 = obj1;
    NSString *ke2 = obj2;
    return [ke1 compare:ke2];
}];

过滤

[dic keysOfEntriesPassingTest:<#^BOOL(id key, id obj, BOOL *stop)predicate#>];
Mutable版的字典，多了增删的方法
NSMutableDictionary *dicmutable = [NSMutableDictionary dictionaryWithDictionary:dic];

添加

[dicmutable setObject:@"icepy" forKey:@"io"];
NSLog(@"%@",dicmutable);

删除

[dicmutable removeObjectForKey:@"build"];
NSLog(@"%@",dicmutable);