Since Java 5 you can use Arrays.toString(arr) or Arrays.deepToString(arr) for arrays within arrays. Note that the Object[] version calls .toString() on each object in the array. The output is even decorated in the exact way you’re asking. Examples: Simple Array: String[] array = new String[] {“John”, “Mary”, “Bob”}; System.out.println(Arrays.toString(array)); Output: [John, Mary, Bob] Nested Array: … Read more
You can either use array declaration or array literal (but only when you declare and affect the variable right away, array literals cannot be used for re-assigning an array). For primitive types: int[] myIntArray = new int[3]; int[] myIntArray = {1, 2, 3}; int[] myIntArray = new int[]{1, 2, 3}; // Since Java 8. Doc … Read more
With JavaScript 1.6 / ECMAScript 5 you can use the native filter method of an Array in the following way to get an array with unique values: function onlyUnique(value, index, self) { return self.indexOf(value) === index; } // usage example: var a = [‘a’, 1, ‘a’, 2, ‘1’]; var unique = a.filter(onlyUnique); console.log(unique); // [‘a’, … Read more
Arrays.asList(yourArray).contains(yourValue) Warning: this doesn’t work for arrays of primitives (see the comments). Since java-8 you can now use Streams. String[] values = {“AB”,”BC”,”CD”,”AE”}; boolean contains = Arrays.stream(values).anyMatch(“s”::equals); To check whether an array of int, double or long contains a value use IntStream, DoubleStream or LongStream respectively. Example int[] a = {1,2,3,4}; boolean contains = IntStream.of(a).anyMatch(x … Read more
Use the Array.prototype.push method to append values to the end of an array: // initialize array var arr = [ “Hi”, “Hello”, “Bonjour” ]; // append new value to the array arr.push(“Hola”); console.log(arr); You can use the push() function to append more than one value to an array in a single call: // initialize array … Read more
There are different ways to delete an array element, where some are more useful for some specific tasks than others. Deleting a single array element If you want to delete just one array element you can use unset() or alternatively \array_splice(). If you know the value and don’t know the key to delete the element … Read more
The method given in the ECMAScript standard to find the class of Object is to use the toString method from Object.prototype. if(Object.prototype.toString.call(someVar) === ‘[object Array]’) { alert(‘Array!’); } Or you could use typeof to test if it is a string: if(typeof someVar === ‘string’) { someVar = [someVar]; } Or if you’re not concerned about … Read more
It’s easy enough to write your own comparison function: function compare( a, b ) { if ( a.last_nom < b.last_nom ){ return -1; } if ( a.last_nom > b.last_nom ){ return 1; } return 0; } objs.sort( compare ); Or inline (c/o Marco Demaio): objs.sort((a,b) => (a.last_nom > b.last_nom) ? 1 : ((b.last_nom > a.last_nom) … Read more
Checking for undefined-ness is not an accurate way of testing whether a key exists. What if the key exists but the value is actually undefined? var obj = { key: undefined }; console.log(obj[“key”] !== undefined); // false, but the key exists! You should instead use the in operator: var obj = { key: undefined }; … Read more
Three main options: for (var i = 0; i < xs.length; i++) { console.log(xs[i]); } xs.forEach((x, i) => console.log(x)); for (const x of xs) { console.log(x); } Detailed examples are below. 1. Sequential for loop: var myStringArray = [“Hello”,”World”]; var arrayLength = myStringArray.length; for (var i = 0; i < arrayLength; i++) { console.log(myStringArray[i]); //Do … Read more