OC_字典

*不可变字典*

不可变字典的定义

// 初始化定义一个空的字典NSDictionary *dic = [[NSDictionary alloc] init];// 便利器构造器定义一个空的字典NSDictionary *dic = [NSDictionary dictionary];// 字面量定义一个字典NSDictionary *dic = @{@"1" : @"2", @"3" : @"4", @"5" : @"6", @"7" : @"8"};// 初始化定义一个字典NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys:@"1", @"2", @"3", @"4", nil];// key是唯一的, 但是value可以重复// key不能为空

count 当前有多少键值对

NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys:@"1", @"2", @"3", @"4", nil];NSLog(@"%ld", dic.count);

objectForKey: 通过对应的key找到相应的value

NSDictionary *dic = [[NSDictionary alloc] initWithObjectsAndKeys:@"1", @"2", @"3", @"4", nil];NSLog(@"%@", [dic objectForKey:@"2"]);//也可以NSLog(@"%@",dic[@"2"]);

获取字典里所有的key 和 value

NSLog(@"%@", dic.allKeys);NSLog(@"%@", dic.allValues);

可变字典

可变字典的定义

// 空的字典NSMutableDictionary *dic = [NSMutableDictionary dictionary];// 非空字典NSMutableDictionary *dic = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"1", @"2", @"3", @"4", @"5", @"6",  nil];

forin 遍历字典

// forin 的前部分是字典里的keyNSMutableDictionary *dic = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"1", @"2", @"3", @"4", @"5", @"6",  nil];for (NSString *str in dic) {    NSLog(@"%@", [dic objectForKey:str]);}

setObject:

NSMutableDictionary *dic = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"1", @"2", @"3", @"4", @"5", @"6",  nil];// 对可变的字典,当前的key不存在的时候,进行键值对的添加,当key存在了,进行值的修改[dic setObject:@"7" forKey:@"8"];NSLog(@"%@", dic);[dic setObject:@"100" forKey:@"6"];NSLog(@"%@", dic);

removeObjectForKey: 移除键值对

NSMutableDictionary *dic = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"1", @"2", @"3", @"4", @"5", @"6",  nil];[dic removeObjectForKey:@"8"];NSLog(@"%@", dic);// 移除所有键值对[dic removeAllObjects];NSLog(@"%@", dic);

字典里嵌套数组

NSArray *arr1 = @[@"1", @"2", @"3", @"4"];NSArray *arr2 = @[@"5", @"6", @"7", @"8"];NSMutableDictionary *dic = [NSMutableDictionary dictionaryWithObjectsAndKeys:arr1, @"arr1", arr2, @"arr2", nil];for (NSString *str in dic) {    // 针对对应的key找到value, value是一个数组,所以用一个数组对象来接受    NSArray *arr = dic[str]; //也可以NSArray *arr = [dic objectForKey:str];    for (NSString *temp in arr) {        NSLog(@"%@", temp);    }}

数组里嵌套字典

NSMutableDictionary *dic1 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"杨林", @"name", @"19", @"age", nil];NSMutableDictionary *dic2 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"李牧燃", @"name", @"22", @"age", nil];NSMutableDictionary *dic3 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"腾飞", @"name", @"23", @"age", nil];NSArray * arr = @[dic1, dic2, dic3];for (NSMutableDictionary *dic in arr) {    for (NSString *str in dic) {        NSLog(@"%@", dic[str]);    }}

字典里嵌套数组再嵌套字典

NSMutableDictionary *dic1 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"杨林", @"name", @"19", @"age", nil];NSMutableDictionary *dic2 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"李牧燃", @"name", @"22", @"age", nil];NSMutableDictionary *dic3 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"腾飞", @"name", @"23", @"age", nil];NSArray *arr1 = @[dic1, dic2];NSArray *arr2 = @[dic3];NSDictionary *bigDic = [NSDictionary dictionaryWithObjectsAndKeys:arr1, @"arr1", arr2, @"arr2", nil];for (NSArray *arr in bigDic) {    NSArray *temp = bigDic[arr];    for (NSMutableDictionary * dic in temp) {        for (NSString *str in dic) {            NSLog(@"%@", dic[str]);        }    }}

省市区字典数组

// 准备工作NSString *path = @"/Users/dlios/Documents/OC_省市区字典数组/OC_省市区字典数组/area.txt";// 根据路径产生相应的字符串NSString *str = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];// 对字符串逐行进行切割NSArray *strArr = [str componentsSeparatedByString:@"\n"];// 创建一个省数组NSMutableArray *proArr = [NSMutableArray array];for (NSString *temp in strArr) {    if (![temp hasPrefix:@" "]) {        // 创建一个省字典        NSMutableDictionary *proDic = [NSMutableDictionary dictionary];        // 给省字典添加键值对        // 省名        [proDic setObject:temp forKey:@"proName"];        // 创建一个市数组        NSMutableArray *cityArr = [NSMutableArray array];        // 添加到省字典里        [proDic setObject:cityArr forKey:@"cityArr"];        // 把省字典添加到省数组里        [proArr addObject:proDic];    } else if ([temp hasPrefix:@"  "] && ![temp hasPrefix:@"    "]){        // 创建一个市字典        NSMutableDictionary *cityDic = [NSMutableDictionary dictionary];        // 给市字典添加键值对        // 市名        [cityDic setObject:temp forKey:@"cityName"];        // 创建一个区数组        NSMutableArray *zoneArr = [NSMutableArray array];        // 添加到市字典里          [cityDic setObject:zoneArr forKey:@"zoneArr"];        // 给市字典找一个位置        // 先找到对应的省字典        NSMutableDictionary *proDic = [proArr lastObject];        // 再找到对应的市数组        NSMutableArray *cityArr = proDic[@"cityArr"];        // 将市字典添加到市数组里        [cityArr addObject:cityDic];    } else {        // 先找省字典        NSMutableDictionary *proDic = [proArr lastObject];        // 市数组        NSMutableArray *cityArr = proDic[@"cityArr"];        // 市字典        NSMutableDictionary *cityDic = [cityArr lastObject];        // 区数组        NSMutableArray *zoneArr = cityDic[@"zoneArr"];        // 将区名添加到区数组里        [zoneArr addObject:temp];    }}// forin进行遍历省数组for (NSMutableDictionary *dic in proArr) {    NSLog(@"%@", dic[@"proName"]);    NSMutableArray *city = dic[@"cityArr"];    for (NSMutableDictionary *citydic in city) {        NSLog(@"%@", citydic[@"cityName"]);        NSMutableArray *zoneArr = citydic[@"zoneArr"];        for (NSString *str in zoneArr) {        NSLog(@"%@", str);        }    }}

例题

NSMutableDictionary *book1 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"三国演义", @"name", @"100", @"price", nil];NSMutableDictionary *book2 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"水浒传", @"name", @"200", @"price", nil];NSMutableDictionary *book3 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"西游记", @"name", @"300", @"price", nil];NSMutableArray *arrBook = [NSMutableArray arrayWithObjects:book1, book2, book3, nil];for (NSMutableDictionary *dic in arrBook) {    // if ([dic[@"name"] isEqualToString:@"水浒传"]) {    if ([[dic objectForKey:@"name"] isEqualToString:@"水浒传"]) {    // dic[@"price"] = @"100";    [dic setObject:@"100" forKey:@"price"];    }}for (NSMutableDictionary *dic in arrBook) {    NSLog(@"%@, %@", dic[@"name"], dic[@"price"]);}