# Partial functions

### From HaskellWiki

A **partial function** is a function that is not defined for all possible arguments of the specified type. Examples in the Haskell standard library are:

- ,head: undefined for empty liststail
- : undefined if the index is at least as big as the list length(!!)
- : undefined if the divisor is zerodiv

The opposite is a total function.

There are methods to avoid the use of partial functions.