Functions and Multicolumn Operations

The possibility that users have to define custom functions is common in programming languages. It serves the purpose of letting users specify their own set of operations to be executed repeatedly with different data and parameters. Multicolumn operations are useful to repeat operations on data frame columns, a common requirement in many situations. As usual in data science, size matters, and the scalability of a solution could be the single most important feature. Derived from the general definition of a user‐defined function, a simplified form has been introduced with the name of anonymous functions. These ones follow the same logic as general user‐defined functions, but with some constraints and a special syntax. The general syntax for a user‐defined function in Python follows a conventional schema and adopts the peculiar Python syntactic rule about indentation.