arrayaccess

问题 I would like to access an numpy array data via an index idx , but still preserving the order in data . Below is an example where the array is accessed with an order different from the one in the original array. In [125]: data = np.array([2, 2.2, 2.5]) In [126]: idx=np.array([1,0]) In [127]: data[idx] Out[127]: array([2.2, 2. ]) I hope to get [2,2.2] instead. Is there a highly efficient way to do so? In my problem setting, I have the data with more than a million floating-point numbers, and

问题 I am trying to understand the idea behind ArrayAccess Interface, I dont understand what each method is about, If those methods(functions) are "built in" functions and ArrayAccess Interface(also "built in") is only "make sure" i am going to implement those "built in" methods(functions) I am trying to understand what does each of thoes functions is doing with our code "Behind the scenes". function offsetSet($offset, $value); function offsetGet($offset); function offsetUnset($offset); function

问题 Is it possible to allow an Array or an object that implements ArrayAccess? For example: class Config implements ArrayAccess { ... } class I_Use_A_Config { public function __construct(Array $test) ... } I want to be able to pass in either an Array or ArrayAccess. Is there a clean way to do this other than manually checking the parameter type? 回答1: No, there is no "clean" way of doing it. The array type is a primitive type . Objects that implement the ArrayAccess interface are based on classes,

问题 EDIT: I realized the amount of text might be intimidating. The essence of this question: How to implement ArrayAccess in a way that makes setting multidimensional values possible? I am aware that this was discussed here already but I seem unable to implement the ArrayAccess interface correctly. Basically, I've got a class to handle the app configuration with an array and implemented ArrayAccess . Retrieving values works fine, even values from nested keys ( $port = $config['app']['port']; ).

问题 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 7 years ago . When implementing an object using ArrayAccess or ArrayObject , to some operations it's a perfectly normal array (for instance a foreach() statement).

问题 I have an object that is a collection of objects, behaving like an array. It's a database result object. Something like the following: $users = User::get(); foreach ($users as $user) echo $user->name . "\n"; The $users variable is an object that implements ArrayAccess and Countable interfaces. I'd like to sort and filter this "array", but I can't use array functions on it: $users = User::get(); $users = array_filter($users, function($user) {return $user->source == "Twitter";}); => Warning:

问题 Consider: int sum(const int numbers[], const int size){ if (size == 0) return 0; else return numbers[0] + sum(numbers+1, size-1); } This is a simple recursive function from MIT 6.096 for adding an arbitrary number of integers, and it works. The thing I cannot understand is in the last line: How does numbers+1 work, given numbers[] is an int array and you shouldn't be able to add an integer to an int[] constant? 回答1: how does "numbers+1" work, given numbers[] is an int array and you shouldn't

问题 As many of you already know, PHP 5.4 alpha has been released. I have a question regarding the following. Simplified string offset reading. $str[1][0] is now a legal construct. How exactly does $str[1][0] work? EDIT: http://php.net/releases/NEWS_5_4_0_alpha1.txt 回答1: This is a side effect, and was mentioned in the proposal here: http://php.markmail.org/thread/yiujwve6zdw37tpv The feature is speed/optimization of string offsets. Hi, Recently I noticed that reading of string offset is performed

问题 First, a quote from the ole' manual on ArrayAccess::offsetSet(): This function is not called in assignments by reference and otherwise indirect changes to array dimensions overloaded with ArrayAccess (indirect in the sense they are made not by changing the dimension directly, but by changing a sub-dimension or sub-property or assigning the array dimension by reference to another variable). Instead, ArrayAccess::offsetGet() is called. The operation will only be successful if that method

问题 The best I could come up is function is_array_alike($array) { return is_array($array) || (is_object($array) && $array instanceof ArrayAccess && $array instanceof Traversable && $array instanceof Serializable && $array instanceof Countable); } Ugh. Is there something more pretty? Edit: the test for is_object seems unnecessary. I have added a section to the instanceof PHP manual about that. 回答1: Well, since you did use the word "pretty" in your post, just a quick suggestion on cosmetic changes