How do you implement queue in Scala?

How do you implement queue in Scala?

In Scala, Queue is implemented as a pair of lists. One is used to insert the elements and second to contain deleted elements. Elements are added to the first list and removed from the second list. The two most basic operations of Queue are Enqueue and Dequeue.

Does Scala have immutable collections?

Even though the static type of such a collection provides no operations for modifying the collection, it might still be possible that the run-time type is a mutable collection which can be changed by other clients. By default, Scala always picks immutable collections.

How do I create a mutable list in Scala?

Adding elements in ListBuffer:

1. Add single element to the buffer ListBuffer+=( element)
2. Add two or more elements (method has a varargs parameter) ListBuffer+= (element1, element2., elementN )
3. Append one or more elements (uses a varargs parameter) ListBuffer.append( elem1, elem2, elemN)

Is Scala mutable queue thread safe?

So if you do a data. get() before a data. set(), the result will be unsafe, making the whole thread-safety claim pretty useless, unless you have compare-and-swap semantics. This is why mutable data-structures on the JVM are usually not thread-safe, since locks have overhead and you’ll need higher level locks anyway.

How do you declare an array in Scala?

In Scala arrays are immutable objects. You create an array like this: var myArray : Array[String] = new Array[String](10); First you declare variable var myArray to be of type Array[String] .

Which is used to collect data in Scala?

Scala provides rich set of collection library. It contains classes and traits to collect data. These collections can be mutable or immutable. You can use them according to your requirement….Some Significant Methods of Traversable Trait.

Method	Description
def head: A	It returns the first element of collection.

Which of the following is immutable in Scala?

“Immutable” means that you can’t change (mutate) your variables; you mark them as final in Java, or use the val keyword in Scala. More important than you not changing your variables is that other programmers can’t change your variables, and you can’t change theirs.

What is the difference between Array and list in Scala?

A list is a collection which contains immutable data. Following are the point of difference between lists and array in Scala: Lists are immutable whereas arrays are mutable in Scala. Lists represents a linked list whereas arrays are flat.

Is Scala mutable HashMap thread-safe?

To get a thread-safe mutable map, you can mix the SynchronizedMap trait trait into whatever particular map implementation you desire. This example begins with an import of two traits, Map and SynchronizedMap, and one class, HashMap, from package scala. collection.

How to use a queue in Scala ( mutable, immutable )?

A Queue is a collection class that extends from Iterable and Traversable, so it has all the usual collection methods, including foreach, map, etc. See the Queue Scaladoc for more information. this post is sponsored by my books

Is the run time type of a Scala collection immutable?

Even though the static type of such a collection provides no operations for modifying the collection, it might still be possible that the run-time type is a mutable collection which can be changed by other clients. By default, Scala always picks immutable collections.

How to create a queue with initial elements?

You can also create a queue with initial elements: Once you have a mutable queue, add elements to it using +=, ++=, and enqueue, as shown in the following examples: Because a queue is a FIFO, you typically remove elements from the head of the queue, one element at a time, using dequeue:

Are there any aliases for collections in Scala?

Other types aliased are Traversable, Iterable, Seq, IndexedSeq, Iterator, Stream, Vector, StringBuilder, and Range. The following figure shows all collections in package scala.collection. These are all high-level abstract classes or traits, which generally have mutable as well as immutable implementations.