arrays

问题 I have some C++ code that uses a 2D vector and needs to call an external library that uses a pointer the array with rows and col as parameters. So what I need to do is convert my 2d vector into a format that I can shove into foo((float *)data, int rows, int cols) . So 2D Vector data ---code---> foo((float *), int row, int cols) Trying to convert the 2d vector to a 2d array wasn't working very well using Converting 2D vector to 2D array This example uses double pointers and I don't know how to

问题 I've been searching an answer for that but didn't found it. I have an array like: const data2 = [{ "abc":{ companyCity:"Cupertino", conpanyName:"Apple" } }, { "def":{ companyCity:"Mountain View", conpanyName:"Google" } } ] And I'd like to convert to and array like omiting the parent keys: const data3 = [ { companyCity:"Cupertino", companyName:"Apple", }, { companyCity:"Mountain View", companyName:"Google" } ] Perhaps, libraries like lodash have a method to achieve that, but didn't find it.

问题 I've got an object array which I have to group and sort: [ { id: 123, group: 'abc', metadata: { name: 'tom' }, date: ISODate("2019-07-08T20:33:40.475Z") }, { id: 456, group: 'def', metadata: { name: 'bob' }, date: ISODate("2019-07-08T20:33:40.475Z") }, { id: 789, group: 'def', metadata: { name: 'bob' }, date: ISODate("2019-07-10T20:33:40.475Z") }, { id: 234, group: 'ghi', metadata: { name: 'frank' }, date: ISODate("2019-07-10T20:33:40.475Z") }, { id: 567, group: 'abc', metadata: { name: 'tom'

问题 i am developing application in which i send data to server using volley now i want to send data to server in json array but not know how to send in array?? Map<String, String> postParam = new HashMap<String, String>(); postParam.put("Token", "U2FsdGVkX13CFEM="); postParam.put("AppDB", "day"); postParam.put("ContentTypeName", "Users"); JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.POST, AppConfig.URL_REGISTER_WITHOUT_IMG, new JSONObject(postParam), new Response.Listener

问题 I want to write code that adds the doNotInclude method to the Array.prototype object. The purpose of my code is: does not include the index values from the array passed to doNotInclude . Code below: Array.prototype.doNotInclude = function (arr) { //if (!Array.isArray(arr)) arr = [arr]; return this.filter((val, i) => { if (!arr.includes(i)) return val; }); }; ['zero', 'one', 'two', 'three', 'four', 'five', 'six'].doNotInclude([0, 1]) My code executes successfully and returns: [ 'two', 'three',

问题 hello i am trying to count values from array. my ResidentMail table look like id resident_id mail_type 1 10 message 2 10 wellness 3 10 message 4 11 wellness 5 11 wellness 6 11 message this is my array look like array( [0] => [ [0] => [ 'id' => 1 'resident_id' => 10 'mail_type' => 'message' ], [1] => [ 'id' => 2 'resident_id' => int 10 'mail_type' => 'wellness' ], [2] => [ 'id' => 3 'resident_id' => int 10 'mail_type' => 'message' ] ], [1] => [ [0] => [ 'id' => 4 'resident_id' => 11 'mail_type

问题 hello i am trying to count values from array. my ResidentMail table look like id resident_id mail_type 1 10 message 2 10 wellness 3 10 message 4 11 wellness 5 11 wellness 6 11 message this is my array look like array( [0] => [ [0] => [ 'id' => 1 'resident_id' => 10 'mail_type' => 'message' ], [1] => [ 'id' => 2 'resident_id' => int 10 'mail_type' => 'wellness' ], [2] => [ 'id' => 3 'resident_id' => int 10 'mail_type' => 'message' ] ], [1] => [ [0] => [ 'id' => 4 'resident_id' => 11 'mail_type

问题 From Effective Java by Joshua Bloch, Arrays differ from generic type in two important ways. First arrays are covariant. Generics are invariant. Covariant simply means if X is subtype of Y then X[] will also be sub type of Y[]. Arrays are covariant As string is subtype of Object So String[] is subtype of Object[] Invariant simply means irrespective of X being subtype of Y or not , List<X> will not be subType of List<Y>. My question is why the decision to make arrays covariant in Java? There

问题 From Effective Java by Joshua Bloch, Arrays differ from generic type in two important ways. First arrays are covariant. Generics are invariant. Covariant simply means if X is subtype of Y then X[] will also be sub type of Y[]. Arrays are covariant As string is subtype of Object So String[] is subtype of Object[] Invariant simply means irrespective of X being subtype of Y or not , List<X> will not be subType of List<Y>. My question is why the decision to make arrays covariant in Java? There

问题 Is it possible store a few functions in an array by reference or by anonymous function? For example: $array = [fun1, function(){ /*do something*/ }, fun3]; where fun1 and fun3 are defined as function fun1(){/*do something*/} 回答1: As long as your PHP version is >= 5.3 you'll be able to harness anonymous functions and regular functions in your array: function yourFunction($string){ echo $string . " : by reference"; }; $array = array( 'a' => function($string){ echo $string; }, 'b' =>