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// 遍历总结

// 遍历一般有三种 for循环遍历 枚举器(NSEnumerator)遍历 for ... in 遍历

// 1. for循环遍历字典

NSDictionary *dic =@{@"name": @"edition", @"sex": @"man", @"age": @"36"};

NSArray *dicArr = [dic allKeys];

for (NSInteger i = 0; i < dicArr.count; i++) {

    NSString *keyStr = dicAr[i];

    NSString *valueStr = [dic ObjectForKey: keStr];

    NSLog(@"%@: %@", keyStr, valueStr);

}

// 利用for循环遍历字典 首先把所有的key放到一个数组中 然后遍历这个装了key值得数组 再用字符串接收每个key值 再用 ObjectForKey: 方法获得value

//2. 利用枚举器遍历数组

NSArray *arr = @[@"红色", @"绿色", @"黄色", @"白色"];

NSEnumerator *arrEnu = [arr ObjectEnumerator];

id value = nil;

while (value = [arrEnu nextObject]) {

NSLog(@"%@", value);

}

// 用枚举器遍历数组 首先 要具有一个数组 然后创建枚举器 

// 3. 利用枚举器遍历字典 默认输出的是value 

NSDictionary *dic = @{@"name": @"john", @"sex": @"man", @"age": @"20"};

NSEnumerator *dicEnu = [NSEnumerator ObjectEnumerator];

id value = nil;

while (value = [dicEnu nextObject]) {

NSLog(@"%@", value);

}

// 枚举器遍历输出key

NSEnumerator *dicEnu = [dic ObjectEnumerator];

id value = nil;

while (value = [dicEnu nextObject]) {

NSLog(@"%@", dic allKeysForObject:value);

}

// 利用 for...in 遍历数组

NSArray *array = @[@"manfan", @"tangtang", @"laoxiang"];

for(NSString *str in array) {

NSLog(@"%@", str);

}

// 利用for... in遍历字典 默认输出的是字典的key值

NSDictionary *dic = @{@"name": @"yueyeu", @"age": @"23", @"sex": @"woman"};

for(NSString *str in dic){

NSLog(@"%@", [dic objectForKey:str]);

}

// 将数组进行升序降序排列 默认升序排列

NSArray *array = @[@"7", @"27", @"57", @"17"];

NSArray *newArray = [array sortedArrayUsingSelector:@selector(compare:)];

NSLog(@"%@", newArray);

// 排序

NSArray *array = @[@"7", @"27", @"57", @"17"];

NSSortDescriptor *sort = [NSSortDescriptor alloc] initWithKey:nil ascending:YES]; // YES 为升序 NO为降序

NSArray *newArr = [array sortedArrayUsingDescriptors:@[arrSort]];

NSLog(@"%@", newArr);