Domain, Range, And Codomain

Kevin Sookocheff explains the concepts of domain, range, and codomain:

That is, a function relates an input to an output. But, not all input values have to work, and not all output values. For example, you can imagine a function that only works for positive numbers, or a function that only returns natural numbers. To more clearly specify the types and values of a functions input and output, we use the terms domain, range, and codomain.

Speaking as simply as possible, we can define what can go into a function, and what can come out:

  • domain: what can go into a function

  • codomain: what may possibly come out of a function

  • range: what actually comes out of a function

Read on for more, including a couple of examples.  These are important concepts for learning functional programming.

Related Posts

Passing Data To Java In SQL Server 2019

Niels Berglund continues looking at the SQL Server 2019 Extensibility Framework’s support for Java: In Java, there are also helper components, (a topic for future posts), but the integration is not as tight, so when we want to pass data into and out of Java we need to code somewhat more explicit to make data […]

Read More

Working With Key-Value Pairs In Spark

Teena Vashist shows us a few of the functions available with Spark for working with key-value pairs: 1. Creating Key/Value Pair RDD:  The pair RDD arranges the data of a row into two parts. The first part is the Key and the second part is the Value. In the below example, I used a parallelize method to create a RDD, […]

Read More


March 2018
« Feb Apr »