oc block 遍历数组及字典

原遍历数组
NSArray * lines = ...
for (NSString * line in lines) {
   // ...
}
for (int i = 0; i < lines.count; ++i) {
    NSString * s = [lines objectAtIndex:i];
    ...
}

原遍历字典

NSDictionary * dict = …
        NSArray * keys = [dict allKeys];
        for (NSString * key in keys) {
            NSString * value = [dict objectForKey:key];

        }

block遍历
    [lines enumerateObjectsUsingBlock:^(NSString * obj, NSUInteger idx, BOOL *stop) {

    }];

    [_urlArguments enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {

    }];