Reshaping Three-Collar Data Frames to Matrix Format Using R

Here's a summary of the provided information and some additional examples to demonstrate the usage of the `melt()` function in R:

Reshaping Wide Format Data Using R and data.table Package

Merging Rows by Subject Number: A Guide to Longing Data in R

Tidy Data Transformation with Pandas: A Deep Dive into Merging Wide and Long Formats

Advanced Grouping and Reshaping Transformation Using Pandas

Reshaping Data to Plot in R using ggplot2

Reshaping a DataFrame in R: A Step-by-Step Guide