How to convert jsonString to JSONObject in Java
Using org.json library: try { JSONObject jsonObject = new JSONObject(“{\”phonetype\”:\”N95\”,\”cat\”:\”WP\”}”); }catch (JSONException err){ Log.d(“Error”, err.toString()); }
arrays
Get all non-unique values (i.e.: duplicate/more than one occurrence) in an array
You could sort the array and then run through it and then see if the next (or previous) index is the same as the current. Assuming your sort algorithm is good, this should be less than O(n2): const findDuplicates = (arr) => { let sorted_arr = arr.slice().sort(); // You can define the comparing function here. … Read more
How does `Array.prototype.slice.call` work?
What happens under the hood is that when .slice() is called normally, this is an Array, and then it just iterates over that Array, and does its work. How is this in the .slice() function an Array? Because when you do: object.method(); …the object automatically becomes the value of this in the method(). So with: … Read more
What’s the best way to get the last element of an array without deleting it?
Try end: $myLastElement = end($yourArray); Note that this doesn’t just return the last element of the passed array, it also modifies the array’s internal pointer, which is used by current, each, prev, and next. For PHP >= 7.3.0: If you are using PHP version 7.3.0 or later, you can use array_key_last, which returns the last … Read more
How to convert int[] into List in Java?
Streams In Java 8+ you can make a stream of your int array. Call either Arrays.stream or IntStream.of. Call IntStream#boxed to use boxing conversion from int primitive to Integer objects. Collect into a list using Stream.collect( Collectors.toList() ). Or more simply in Java 16+, call Stream#toList(). Example: int[] ints = {1,2,3}; List<Integer> list = Arrays.stream(ints).boxed().collect(Collectors.toList()); … Read more
What are the advantages of NumPy over regular Python lists?
NumPy’s arrays are more compact than Python lists — a list of lists as you describe, in Python, would take at least 20 MB or so, while a NumPy 3D array with single-precision floats in the cells would fit in 4 MB. Access in reading and writing items is also faster with NumPy. Maybe you … Read more
How do I check in JavaScript if a value exists at a certain array index?
Conceptually, arrays in JavaScript contain array.length elements, starting with array[0] up until array[array.length – 1]. An array element with index i is defined to be part of the array if i is between 0 and array.length – 1 inclusive. If i is not in this range it’s not in the array. So by concept, arrays … Read more
Create an array with same element repeated multiple times
In ES6 using Array fill() method console.log( Array(5).fill(2) ) //=> [2, 2, 2, 2, 2]
A quick and easy way to join array elements with a separator (the opposite of split) in Java [duplicate]
Using Java 8 you can do this in a very clean way: String.join(delimiter, elements); This works in three ways: 1) directly specifying the elements String joined1 = String.join(“,”, “a”, “b”, “c”); 2) using arrays String[] array = new String[] { “a”, “b”, “c” }; String joined2 = String.join(“,”, array); 3) using iterables List<String> list = … Read more
How to check if an element is in an array
Swift 2, 3, 4, 5: let elements = [1, 2, 3, 4, 5] if elements.contains(5) { print(“yes”) } contains() is a protocol extension method of SequenceType (for sequences of Equatable elements) and not a global method as in earlier releases. Remarks: This contains() method requires that the sequence elements adopt the Equatable protocol, compare e.g. … Read more