Binning

Binning is a way to group many continuous values into a smaller number of bins.Simply it is the process of transforming numerical variables into categorical counterparts.

1. Equal Frequency Binning

   Equal-frequency binning divides the data set into bins that all have the same number of samples. Quantile binning assigns the same number of observations to each bin. If there are 4 bins means, each bin will have equal number of points.

2. Equal Width Binning:

   Equal width binning is probably the most popular way of doing discretization. This means that after the binning, all bins have equal width, or represent an equal range of the original variable values, no matter how many cases are in each bin. If the data is evenly distributed, it is not sparse, or has no outliers, then use this method.
   Example: [10,20,30,40,50,70,80,90,100]
   If number of bins is 2, then output is two bins created by the condition if the data<50 assign to bin1,else assign to bin2.