Scala uses the Java Virtual Machine (JVM) during runtime, which gives it some speed over Python in most cases. Python is dynamically typed and this reduces speed. Compiled languages are faster than interpreted languages. Let's explore some important factors to consider before deciding on Scala vs Python as the main programming language for Apache Spark.
Scala allows you to express general programming patterns in a very concise and effective format while minimising the number of lines of code. The choice of programming language for Apache Spark is a subjective matter, as the reasons why a particular data scientist or data analyst likes Python or Scala for Apache Spark may not always apply to others. Many organisations favour the speed and simplicity of Spark, which supports many application programming interfaces (APIs) available from languages such as Java, R, Python and Scala. Scala offers many advanced programming features, but it is not necessary to use any of them when writing Spark code.
Scala is also ideal for low-level Spark programming and for easy navigation directly to the underlying source code. If you have enough experience with any statically typed programming language such as Java, you can stop worrying about not using Scala at all. Using Scala for Spark provides access to the latest features of the Spark framework, as they are first available in Scala and then ported to Python. Refactoring program code from a statically typed language like Scala is much easier and hassle-free than refactoring code from a dynamic language like Python.
You can use the basic programming features of Scala with the IntelliJ IDE and get useful features like type hints and compile-time checks for free. Scala and Python languages are equally expressive in the context of Spark, so using Scala or Python can achieve the desired functionality. Data scientists often prefer to learn both Scala for Spark and Python for Spark, but Python is often the second favourite language for Apache Spark, as Scala was the first. Both Python and Scala are general-purpose programming languages that support the object-oriented model for creating applications.
A quick look at the salaries offered by Python and Scala skills shows that Scala as a skill offers more salary in the job market than Python. Learning Scala enriches a programmer's knowledge of several novel abstractions in the type system, novel functional programming features and immutable data. Performance is mediocre when Python programming code is used to make calls to Spark libraries, but if there is a lot of processing involved, Python code becomes much slower than the equivalent Scala code.