Metaprogramming with DataFrames

In this section, you will learn about implementing the concept of metaprogramming to dataframes. Dataframes are data structures used for expressing data efficiently. So, using metaprogramming techniques helps speed up the process of dealing with data frames, by automated generation of repetitive tasks and easy syntax.

Getting ready

To get started with this section, you must install the DataArrays, DataFrames, and DataFramesMeta packages of Julia. They can be installed using the Pkg.add() function. Check for successful installation by executing the following in the REPL:

using DataFrames
using DataArrays
using DataFramesMeta

How to do it...

Let's start with the @with macro. It is used to express the columns of DataFrames as symbols. Let's verify this and play with the macro. Before that you need to define a DataFrame. Here is how you do it:

df = DataFrame(a = [1,2,3], b = [4,5,6])
@with(df, :b + 1)

This would add +1 to every value in the y column of the data frame...