for..in遍历，枚举器

#pragma mark ------------for循环遍历集合中的元素------

//创建一个数组，包含5个字符串对象，倒序取出数组中的所有元素，并存储到另一可变数组中

NSArray *array = @[@"1", @"2", @"3", @"4", @"5"];

NSMutableArray *marray = [NSMutableArray arrayWithCapacity:0];

for (NSInteger i = [array count] - 1; i >= 0 ; i --) {

[marray addObject:array[i]];

}

NSLog(@"marray is %@", marray);

NSDictionary *dic = @{@"name":@"zhonger",@"sex":@"m", @"age":@"29"};

NSArray *key = [dic allKeys];

NSArray *value = [dic allValues];

for (int i = 0; i < [key count]; i ++) {

//NSLog(@"%@ = %@",key[i], value[i]);

//NSLog(@"%@", [dic objectForKey:key[i]]);

NSLog(@"%@",dic[key[i]]);

//数组访问元素或者对象的方法是？  objectAtIndex:

//数组访问元素的语法糖？ 数组对象[下标]

//字典访问value值的方法是? object ForKey:

//字典访问值的语法糖? 字典对象[key]

}

//创建一个集体，保存三条信息，遍历得到每一条信息

NSSet *set = [NSSet setWithObjects:@"1", @"888888", @"3", nil];

NSArray *allSet = [set allObjects];

for (int i = 0; i < [allSet count]; i ++) {

NSLog(@"allSet is %@",allSet[i]);

}

#pragma mark ------------枚举器 NSEnumerator------

NSArray *enumArray = @[@"jinkangda", @"zhubada", @"dazi", @"bada"];

//创建一个枚举器，依附于数组

NSEnumerator *rator = [enumArray objectEnumerator];  //正序

//创建一个对象

id object = nil;   //容量为空

while (object = [rator nextObject]) {

NSLog(@"正序＝＝%@",object);

}

NSEnumerator *rator1 = [enumArray reverseObjectEnumerator];

id object1 = nil;

while (object1 = [rator1 nextObject]) {

NSLog(@"倒序＝＝%@",object1);

}

//字典枚举遍历

NSDictionary *enumDic =

@{@"key1":@{@"key1":@"value1"},

@"key2":@{@"key2":@"value2"},

@"key3":@{@"key3":@"value3"}};

NSEnumerator *dicRator = [enumDic objectEnumerator];

id value1 = nil;

while (value1 = [dicRator nextObject]) {

NSLog(@"value1 is  %@",value1);

}

#pragma mark   ------------for...in..快速枚举------

//type *object 代表从集合中获取的对象类型  object只是一个名称而已，只需要满足变量命名法则就行

//collection 代表遍历的集合，要在哪个集合中遍历

//statements 遍历中需要执行的操作，比如使用枚举出来的对象实现某些功能

/*

for (<#type *object#> in <#collection#>) {

<#statements#>

}*/

for (id object in enumArray) {

NSLog(@"-----%@",object);

}

//使用forin遍历获取字典中的每个value

//在字典中遍历key，通过得到每一个key值得到每一个value

for (id key in enumDic) {

//NSLog(@"%@",[enumDic objectForKey:key]);

NSLog(@"%@",enumDic[key]);

for (id key1 in enumDic[key]) {

NSLog(@"%@",enumDic[key][key1]);

// NSLog(@"%@",[[enumDic objectForKey:key]objectForKey:key1]);

}

}

//定义⼀一个数组, 包含5个字符串对象, 取出数组中所有字 符串, 并拼接⽣生成⼀一个新的字符串。

NSArray *ar = @[@"I", @"L", @"o", @"v", @"eyou"];

NSMutableString *mstr = [[NSMutableString alloc]initWithCapacity:0];

for (id object in ar) {

//[mstr stringByAppendingString:object];

[mstr appendString:object];

}

NSLog(@"%@",mstr);