遍历数组和字典

1.遍历字典
NSDictionary *dictionary = @{@"name": @"jack", @"age": @"18"};

1>for (NSString *key in dictionary) {
    id obj = dictionary[key];
}

2>NSArray *keyArray = [dictionary allKeys];
NSArray *valueArray = [dictionary allValues];
for (NSString *key in keyArray) {
    id obj = valueArray[key];
}

3>[dictionary enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
    *stop = YES;
}];

2.遍历数组
NSArray *array = @[@"jack", @"lucy"];

1>for (NSString *str in array) {

}

2>[array enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {

}];

3>迭代器遍历数组
NSEnumerator *enumerator = [array objectEnumerator];
[enumerator allObjects];//有值
id obj = nil;
while (obj = [enumerator nextObject]) {

}
[enumerator allObjects];//返回nil