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) {

}];