How to convert vector to array
There’s a fairly simple trick to do so, since the spec now guarantees vectors store their elements contiguously: std::vector<double> v; double* a = &v[0];
arrays
Convert array to JSON
Script for backward-compatibility: https://github.com/douglascrockford/JSON-js/blob/master/json2.js And call: var myJsonString = JSON.stringify(yourArray); Note: The JSON object is now part of most modern web browsers (IE 8 & above). See caniuse for full listing. Credit goes to: @Spudley for his comment below
Array.size() vs Array.length
Array.size() is not a valid method Always use the length property There is a library or script adding the size method to the array prototype since this is not a native array method. This is commonly done to add support for a custom getter. An example of using this would be when you want to … Read more
How do I convert a Stream into a byte[] in C#? [duplicate]
The shortest solution I know: using(var memoryStream = new MemoryStream()) { sourceStream.CopyTo(memoryStream); return memoryStream.ToArray(); }
Difference between map and collect in Ruby?
There’s no difference, in fact map is implemented in C as rb_ary_collect and enum_collect (eg. there is a difference between map on an array and on any other enum, but no difference between map and collect). Why do both map and collect exist in Ruby? The map function has many naming conventions in different languages. … Read more
PHP multidimensional array search by value
function searchForId($id, $array) { foreach ($array as $key => $val) { if ($val[‘uid’] === $id) { return $key; } } return null; } This will work. You should call it like this: $id = searchForId(‘100’, $userdb); It is important to know that if you are using === operator compared types have to be exactly same, … Read more
How to convert an array to object in PHP?
In the simplest case, it’s probably sufficient to “cast” the array as an object: $object = (object) $array; Another option would be to instantiate a standard class as a variable, and loop through your array while re-assigning the values: $object = new stdClass(); foreach ($array as $key => $value) { $object->$key = $value; } As … Read more
How can I convert the “arguments” object to an array in JavaScript?
ES6 using rest parameters If you are able to use ES6 you can use: Rest Parameters function sortArgs(…args) { return args.sort(function (a, b) { return a – b; }); } document.body.innerHTML = sortArgs(12, 4, 6, 8).toString(); As you can read in the link The rest parameter syntax allows us to represent an indefinite number of … Read more
How to get character array from a string?
Note: This is not unicode compliant. “I💖U”.split(”) results in the 4 character array [“I”, “�”, “�”, “u”] which can lead to dangerous bugs. See answers below for safe alternatives. Just split it by an empty string. var output = “Hello world!”.split(”); console.log(output); See the String.prototype.split() MDN docs.
What is array to pointer decay?
It’s said that arrays “decay” into pointers. A C++ array declared as int numbers [5] cannot be re-pointed, i.e. you can’t say numbers = 0x5a5aff23. More importantly the term decay signifies loss of type and dimension; numbers decay into int* by losing the dimension information (count 5) and the type is not int [5] any … Read more