Introduction to Functions

Before we understand what a function is, we need to classify the types of relationships that 2 data sets can have with each other when input variables (Arguments) in 1 data set is mapped onto the output variables (Images) in another data set. 

For example, in each of the 4 diagrams above, the argument 1 is mapped onto the image A. 

There are 4 types of relationships:

• 1 to 1 relationship: Each argument is mapped to exactly one distinct image. Conversely, each image has only one distinct argument. 

• 1 to Many relationship: Each argument is mapped to one or more images (1 is mapped to both A and B). Not every image has a distinct argument. For example A and B both have the argument 1.