Iterator.remove() is safe, you can use it like this: List<String> list = new ArrayList<>(); // This is a clever way to create the iterator and call iterator.hasNext() like // you would do in a while-loop. It would be the same as doing: // Iterator<String> iterator = list.iterator(); // while (iterator.hasNext()) { for (Iterator<String> iterator = … Read more
The reason is that one construct: var a = []; // Create a new empty array. a[5] = 5; // Perfectly legal JavaScript that resizes the array. for (var i = 0; i < a.length; i++) { // Iterate over numeric indexes from 0 to 5, as everyone expects. console.log(a[i]); } /* Will display: undefined … Read more
foreach supports iteration over three different kinds of values: Arrays Normal objects Traversable objects In the following, I will try to explain precisely how iteration works in different cases. By far the simplest case is Traversable objects, as for these foreach is essentially only syntax sugar for code along these lines: foreach ($it as $k … Read more
If you’re only interested in the keys, you can iterate through the keySet() of the map: Map<String, Object> map = …; for (String key : map.keySet()) { // … } If you only need the values, use values(): for (Object value : map.values()) { // … } Finally, if you want both the key and … Read more
Map<String, String> map = … for (Map.Entry<String, String> entry : map.entrySet()) { System.out.println(entry.getKey() + “/” + entry.getValue()); } On Java 10+: for (var entry : map.entrySet()) { System.out.println(entry.getKey() + “/” + entry.getValue()); }