Search results
Results from the WOW.Com Content Network
The loop calls the Iterator::next method on the iterator before executing the loop body. If Iterator::next returns Some(_), the value inside is assigned to the pattern and the loop body is executed; if it returns None, the loop is terminated.
Where some_iterable_object is either a data collection that supports implicit iteration (like a list of employee's names), or may be an iterator itself. Some languages have this in addition to another for-loop syntax; notably, PHP has this type of loop under the name for each, as well as a three-expression for-loop (see below) under the name for.
Introduced in the Java JDK 1.2 release, the java.util.Iterator interface allows the iteration of container classes. Each Iterator provides a next() and hasNext() method, [18]: 294–295 and may optionally support a remove() [18]: 262, 266 method. Iterators are created by the corresponding container class, typically by a method named iterator().
(The Iterable interface provides the iterator() method used by for-each statements.) All Collections have an java.util.Iterator that goes through all of the elements in the Collection. Collection is generic. Any Collection can store any Object. For example, any implementation of Collection<String> contains String objects.
Java has had a standard interface for implementing iterators since its early days, and since Java 5, the "foreach" construction makes it easy to loop over objects that provide the java.lang.Iterable interface. (The Java collections framework and other collections frameworks, typically provide iterators for all collections.)
Iterators constitute alternative language constructs to loops, which ensure consistent iterations over specific data structures. They can eventually save time and effort in later coding attempts. In particular, an iterator allows one to repeat the same kind of operation at each node of such a data structure, often in some pre-defined order.
Gift ideas for people who are always cold: Blankets, slippers, towels warmers and more
The Java syntax has been gradually extended in the course of numerous major JDK releases, and now supports abilities such as generic programming and anonymous functions (function literals, called lambda expressions in Java). Since 2017, a new JDK version is released twice a year, with each release improving the language incrementally.