What is an iterable in Scala?

What is an iterable in Scala?

Iterable: A base trait for iterable collections. This is a base trait for all Scala collections that define an iterator method to step through one-by-one the collection’s elements.

What is an iterator in Scala?

An iterator is a way to access elements of a collection one-by-one. It resembles to a collection in terms of syntax but works differently in terms of functionality. An iterator defined for any collection does not load the entire collection into the memory but loads elements one after the other.

What are the two effects of calling next () on an iterator?

The two basic operations on an iterator it are next and hasNext . A call to it. next() will return the next element of the iterator and advance the state of the iterator. Calling next again on the same iterator will then yield the element one beyond the one returned previously.

What is an iterable element?

Iterable is an object, which one can iterate over. Iterators have __next__() method, which returns the next item of the object. Note that every iterator is also an iterable, but not every iterable is an iterator. For example, a list is iterable but a list is not an iterator.

What is foldLeft in Scala?

foldLeft() method is a member of TraversableOnce trait, it is used to collapse elements of collections. It navigates elements from Left to Right order. It is primarily used in recursive functions and prevents stack overflow exceptions.

Is there a next Scala?

The hasNext() method belongs to the Abstract Value Members of the Class AbstractIterator. It is defined in the class Iterator. It checks whether there is a next element available or not. Return Type :It returns true if there is a next element, else it returns false.

Which are valid collection types in the Scala standard library?

Packages

• scala.collection.immutable – Immutable, sequential data-structures such as Vector , List , Range , HashMap or HashSet.
• scala.collection.mutable – Mutable, sequential data-structures such as ArrayBuffer , StringBuilder , HashMap or HashSet.

What is fold in Scala?

The fold function is applicable to both Scala’s Mutable and Immutable collection data structures. The fold method takes an associative binary operator function as parameter and will use it to collapse elements from the collection. The fold method allows you to also specify an initial value.

Which loop is best to work with collections?

While loop It works on any Collection ( List or Set ).

What is difference between for loop and iterator?

Difference between the two traversals In for-each loop, we can’t modify collection, it will throw a ConcurrentModificationException on the other hand with iterator we can modify collection. Modifying a collection simply means removing an element or changing content of an item stored in the collection.

Is list an iterable?

A list is an iterable. But it is not an iterator. If we run the __iter__() method on our list, it will return an iterator.

How do you make an iterator from iterable?

You can get an iterator from any iterable by calling the built-in iter function on the iterable. You can use the built-in next function on an iterator to get the next item from it (you’ll get a StopIteration exception if there are no more items).

Is iterator a collection in Scala?

In summary, iterators behave like collections if one never accesses an iterator again after invoking a method on it. The Scala collection libraries make this explicit with an abstraction IterableOnce, which is a common superclass of Iterable and Iterator.

What is Scala API?

The Scala API is somewhat similar to the Java API. It uses a frame on the left to display package names; clicking on a package name brings up a display of that package in the frame on the right. The and icons indicate whether the item is an object or a class (or both); indicates a trait.

What is iterator in Java?

In Java, Iterator is an interface available in Collection framework in java.util package. It is a Java Cursor used to iterate a collection of objects. It is used to traverse a collection object elements one by one.