{"id":1315,"date":"2026-09-12T12:11:18","date_gmt":"2026-09-12T12:11:18","guid":{"rendered":"https:\/\/prwatech.in\/blog\/?p=1315"},"modified":"2026-09-13T13:55:02","modified_gmt":"2026-09-13T13:55:02","slug":"scala-commands-for-spark","status":"publish","type":"post","link":"https:\/\/prwatech.in\/blog\/apache-spark\/apache-spark-scala\/scala-commands-for-spark\/","title":{"rendered":"Scala commands for Spark"},"content":{"rendered":"

Scala Commands for Spark<\/h1>\n

This is a working reference to the core Scala language commands<\/a> every Spark developer runs into early on, expressions, values, functions, classes, loops, and collections, each with a short explanation and example.<\/p>\n

Expressions<\/h2>\n

An expression is simply a computable statement. Typed into the Scala shell, it evaluates immediately and returns a result.<\/p>\n

scala> 12 * 10<\/em>
\nres0: Int = 120<\/em><\/p>\n

\"Scala<\/strong><\/p>\n

Printing Output With println<\/h2>\n

You can print the result of an expression directly using println<\/b><\/strong>.<\/p>\n

\"scala<\/strong><\/p>\n

scala> println(“Hello, ” + “Prwatech”)<\/p>\n

\"scala<\/strong><\/p>\n

Values<\/strong><\/h3>\n

The val<\/b><\/strong>\u00a0keyword names the result of an expression. Referencing a value later does not recompute it, it stays fixed.<\/p>\n

Here such as\u00a0 \u2018x\u2019 is value \u201cReferencing a value doesn\u2019t re-compute it\u201d<\/p>\n

\"values\"<\/strong><\/p>\n

Variables<\/h2>\n

Variables behave like values, except you can reassign them. Define one with the var<\/b><\/strong>\u00a0keyword.<\/p>\n

var x = 6 + 4
\nx = 10<\/p>\n

\"Variable\"<\/strong><\/p>\n

Blocks<\/h2>\n

Surrounding a group of expressions with curly braces combines them into a block. The result of the last expression inside the block becomes the result of the block as a whole.<\/p>\n

\"spark<\/strong><\/p>\n

\"apache<\/strong><\/p>\n

Functions<\/strong><\/h3>\n

Functions<\/h2>\n

Functions are expressions that take parameters. You can define an anonymous function, one with no name, using arrow syntax, where the parameter list sits to the left of the arrow and the expression using it sits to the right.<\/p>\n

On the left of\u00a0=,>\u00a0is a list of parameters. On the right is an expression involving the parameters.<\/p>\n

You can also name functions.<\/p>\n

\"function<\/strong><\/p>\n

Functions can also be given a name.<\/p>\n

\"spark<\/strong><\/p>\n

A function may take multiple parameters.<\/p>\n

\"spark<\/strong><\/p>\n

Or it can take no parameters at all.<\/p>\n

\"spark<\/strong><\/p>\n

Methods<\/h2>\n

Methods look and behave much like functions, with a few key differences. A method is defined with the def<\/b><\/strong>\u00a0keyword, and its return type is declared after the parameter list, following a colon.<\/p>\n

\"Methods<\/strong><\/p>\n

A method can also take multiple parameter lists, one set of parentheses after another.<\/p>\n

\"Methods<\/strong><\/p>\n

Classes<\/strong><\/h3>\n

You can define classes with the class keyword followed by its name and constructor parameters.<\/p>\n

\"class<\/strong><\/p>\n

Objects<\/strong><\/h3>\n

Objects are single instances of their own definitions. You can think of them as singletons of their own classes.<\/p>\n

You can define objects with the\u00a0object\u00a0keyword.<\/p>\n

\"You<\/strong><\/p>\n

Singleton Objects<\/h2>\n

Scala classes do not have a static keyword, so a singleton object fills that role instead. Its constructor runs the first time the object is used, it carries all the features of a class, and its constructor cannot take parameters. A singleton object can be imported from anywhere in the program.<\/p>\n

Singleton objects are commonly used in a few situations:<\/p>\n