NSDictionary、NSMutableDictionary及其枚举器的用法

.不可变词典NSDictionary
 
字典初始化
 
NSNumber *numObj = [NSNumber numberWithInt:];
 
以一个元素初始化
 
NSDictionary *dic = [NSDictionary dictionaryWithObject:numObj forKey:@"key"];
 
初始化两个元素
 
NSDictionary *dic = [NSDictionary dictionaryWithObjectsAndKeys:numObj, @"valueKey", numObj2, @"value2",nil];
 
初始化新字典，新字典包含otherDic
 
NSDictionary *dic = [NSDictionary dictionaryWithDictionary:otherDic];
 
以文件内容初始化字典
 
NSDictionary *dic = [NSDictionary dictionaryWithContentsOfFile:path];
 
常用方法
 
获取字典数量
 
NSInteger count = [dic count];
 
通过key获取对应的value对象
 
NSObject *valueObj = [dic objectForKey:@"key"];
 
将字典的key转成枚举对象，用于遍历
 
NSEnumerator *enumerator = [dic keyEnumerator];
 
获取所有键的集合
 
NSArray *keys = [dic allKeys];
 
获取所有值的集合
 
NSArray *values = [dic allValues];
 
.可变数组NSMutableDictionary
 
初始化一个空的可变字典
 
NSMutableDictionary *dic2 = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"v1",@"key1",@"v2",@"key2",nil];
 
NSDictionary *dic3 = [NSDictionary dictionaryWithObject:@"v3" forKey:@"key3"];
 
向字典2对象中添加整个字典对象3
 
[dic2 addEntriesFromDictionary:dic3];
 
向字典2对象中最佳一个新的key3和value3
 
[dic2 setValue:@"value3" forKey:@"key3"];
 
初始化一个空的可变字典
 
NSMutableDictionary *dic1 = [NSMutableDictionary dictionary];
 
将空字典1对象内容设置与字典2对象相同
 
[dic1 setDictionary:dic2];
 
将字典中key1对应的值删除
 
[dic1 removeObjectForKey@"key1"];
 
NSArray *array = [NSArray arrayWithObjects:@"key1", nil];
 
根据指定的数组（key）移除字典1的内容
 
[dic2 removeObjectsForKeys:array];
 
移除字典所有对象
 
[dic1 removeAllObjects];
 
.遍历字典
 
快速枚举
 
for (id key in dic){
 
     id obj = [dic key];
 
     NSLog(@"%@", obj);
 
}
 
NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"value1", @"key1", @"value2", @"key2", nil];
 
for (NSString *key in dict) {
 NSLog(@"key: %@ value: %@", key, dict[key]);
}
 
一般枚举
 
NSArray *keys = [dic allKeys];
 
inr length = [keys count];
 
for (int i = ; i < length；i++){
 
     id key = keys[i];
 
     id obj = dic[key];
 
     NSLog(@"%@", obj);
 
}
 
通过枚举类型枚举
 
NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:@"value1", @"key1", @"value2", @"key2", nil];
 
for (NSString *key in dict) {
 NSLog(@"key: %@ value: %@", key, dict[key]);
}