mutators

问题 I am trying to understand accessors & mutators and why I need them. And my another ask is the middle part of an attribute's method for an example: Accessor : public function getFirstNameAttribute($value) { return ucfirst($value); } Mutator: public function setFirstNameAttribute($value) { $this->attributes['first_name'] = strtolower($value); } Here, we can see getFirstNameAttribute and setFirstNameAttribute methods and I haven't been able to clear the middle part FirstName of them. I will

问题 Assume we have a struct capable of self-mutation that has to happen as part of a background operation: struct Thing { var something = 0 mutating func operation(block: () -> Void) { // Start some background operation dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)) { // Mutate self upon background task completion self.something += 1 block() } } } Now, when I use such a struct in context: var myThing = Thing() myThing.operation { println(myThing.something) } The

问题 Assume we have a struct capable of self-mutation that has to happen as part of a background operation: struct Thing { var something = 0 mutating func operation(block: () -> Void) { // Start some background operation dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)) { // Mutate self upon background task completion self.something += 1 block() } } } Now, when I use such a struct in context: var myThing = Thing() myThing.operation { println(myThing.something) } The

问题 Assume we have a struct capable of self-mutation that has to happen as part of a background operation: struct Thing { var something = 0 mutating func operation(block: () -> Void) { // Start some background operation dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)) { // Mutate self upon background task completion self.something += 1 block() } } } Now, when I use such a struct in context: var myThing = Thing() myThing.operation { println(myThing.something) } The

问题 I'm trying to understand the exact mechanism behind updating a python dictionary using d[key] += diff . I have some helper classes to trace magic method invocations: class sdict(dict): def __setitem__(self, *args, **kargs): print "sdict.__setitem__" return super(sdict, self).__setitem__(*args, **kargs) def __delitem__(self, *args, **kargs): print "sdict.__delitem__" return super(sdict, self).__delitem__(*args, **kargs) def __getitem__(self, *args, **kargs): print "sdict.__getitem__" return

问题 I've been practicing a project which is the classical Nim game. What I've achieved now is: Add, remove, edit, display, players. (Nimsys and NimPlayer) Selecting two players to play a game. (NimGame class) Every time when the game ends, I need to return these two things from NimGame to NimPlayer. Then I can use getter in Nimsys: If the player wins, his/her score +1. Every time after a game, the number of game +1 for the player who played. What I've already tried was to pass the "score" and

问题 I have the following mutator: public function setFormattedCriteriaAttribute($value) { $this->attributes['formatted_criteria'] = serialize($value); } When I call the following why doesn't it update the formatted_criteria value - note the field is listed in my fillable attributes array ? $jobAlert = JobAlert::findOrFail($id); $jobAlert->update([ 'frequency' => $request->frequency, 'criteria' => $criteria, 'formatted_criteria' => ['test'] ]); 回答1: Be sure formated_criteria in your $fillable

问题 I wonder if Laravel have any helper to modify a collection. What I need to do is to make a query with paginate() then check if the logged in users ID match the sender or reciever and based on that add a new value to the output: $userId = Auth::guard('api')->user()->user_id; $allMessages = Conversation::join('users as sender', 'conversations.sender_id', '=', 'sender.user_id') ->join('users as reciver', 'conversations.recipient_id', '=', 'reciver.user_id') ->where('sender_id',$userId)->orWhere(

问题 I wonder if Laravel have any helper to modify a collection. What I need to do is to make a query with paginate() then check if the logged in users ID match the sender or reciever and based on that add a new value to the output: $userId = Auth::guard('api')->user()->user_id; $allMessages = Conversation::join('users as sender', 'conversations.sender_id', '=', 'sender.user_id') ->join('users as reciver', 'conversations.recipient_id', '=', 'reciver.user_id') ->where('sender_id',$userId)->orWhere(

问题 I am currently trying to learn C++ and following an instruction. I've researched on mutators and accessors but I need a simple explanation. class Customer { public: Customer(); ~Customer(); private: string m_name; int m_age; }; Right the code above is in a header file. Within the instructions it is asking me to set a public accessors and mutator for both data. How do I do this? Also it mentions checking the age is not negative in the mutator. I know how to implement the code but I'm just