oc75--不可变字典NSDictionary

//
//  main.m
//  NSDictionary
//
//

#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) {// 1.如何创建NSDictionary *dict1 = [NSDictionary dictionaryWithObject:@"lnj" forKey:@"name"];NSString *name1 = [dict1 objectForKey:@"name"];NSLog(@"name = %@", name1); //lnjNSLog(@"dict1 = %@", dict1);    //dict1 = {name = lnj;}// 注意: key和value 是一一对应NSDictionary *dict2 = [NSDictionary dictionaryWithObjects:@[@"lnj", @"30", @"1.75"] forKeys:@[@"name", @"age", @"height"]];NSLog(@"dict2 = %@", dict2);    //{age = 30;height = "1.75";name = lnj;}
NSLog(@"%@ %@ %@", [dict2 objectForKey:@"name"], [dict2 objectForKey:@"age"], [dict2 objectForKey:@"height"]);//NSDictionary *dict3 = @{key:value};NSDictionary *dict4 = @{@"name": @"lnj"};NSLog(@"%@", dict4[@"name"]);NSDictionary *dict5 = @{@"name":@"lnj", @"age":@"30", @"height":@"1.75"};NSLog(@"dict5 = %@", dict5);//{age = 30;height = "1.75";name = lnj;}NSLog(@"%@ %@ %@", dict5[@"name"], dict5[@"age"], dict5[@"height"]);// 2.字典的遍历NSDictionary *dict6 = @{@"name":@"lnj", @"age":@"30", @"height":@"1.75"};// 2.1如何获取字典中key和value的个数, 在字典中key称之为键, value称之为值NSLog(@"count = %lu", [dict6 count]);for (int i = 0; i < dict6.count; ++i) {// 获取字典中所有的keyNSArray *keys = [dict6 allKeys];// 取出当前位置对应的keyNSLog(@"%@", keys[i]);NSString *key = keys[i];NSString *value = dict6[key];NSLog(@"key = %@, value = %@", key, value);}// 如何通过forin遍历字典, 会将所有的key赋值给前面的objfor (NSString *key in dict6) {NSLog(@"%@", key);NSString *value = dict6[key];NSLog(@"key = %@, value = %@", key, value);}[dict6 enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {NSLog(@"key = %@, value = %@", key, obj);}];// 3.字典文件读写NSDictionary *dict7 = @{@"name":@"lnj", @"age":@"30", @"height":@"1.75"};// XML 扩展名plist[dict7 writeToFile:@"/Users/mctc/Desktop/a.plist" atomically:YES];// 注意: 字典和数组不同, 字典中保存的数据是无序的NSDictionary *newDict8 = [NSDictionary dictionaryWithContentsOfFile:@"/Users/mctc/Desktop/a.plist"];NSLog(@"%@", newDict8);// {age = 30;height = "1.75";name = lnj;}
    NSArray *arr9 = @[@10, @20, @30, @5];[arr9 writeToFile:@"/Users/mctc/Desktop/a.plist" atomically:YES];return 0;
}