Transforming Pandas DataFrames for Advanced Analytics and Visualization: A Step-by-Step Guide Using Python and pandas Library
Here’s the reformatted version of your code, with added sections and improved readability:
Problem
Given a DataFrame df with columns play_id, position, frame, x, and y. The goal is to transform the data into a new format where each position is a separate column, with frames as sub-columns. Empty values are kept in place.
Solution
- Sort values: Sort the DataFrame by
position,frame, andplay_idcolumns.
df = df.sort_values(["position","frame","play_id"])
- Set index: Set the sorted columns as the index of the DataFrame.
df = df.set_index(["position","frame","play_id"])
- Stack values: Use the
stack()method to transform each row into a single value, withcoordas a suffix.
df = df.stack()
- Reindex and unstack: Reindex the DataFrame with new column names for
position,frame,play_id, andcoord. Unstack the values again to create separate columns for each position.
df = df.reindex(df.index.set_names(["position","frame","play_id","coord"])).unstack([0,1,3])
- Output: Print the resulting DataFrame.
Complete Code
import pandas as pd
# Sample data
data = """
play_id position frame x y
1 A_1 1 0.1 0.1
1 A_2 1 0.1 0.1
1 B_1 1 0.1 0.1
1 A_1 2 0.1 0.1
1 A_2 2 0.1 0.1
1 B_1 2 0.1 0.1
2 A_1 1 0.1 0.1
2 B_1 1 0.1 0.1
2 B_2 1 0.1 0.1
2 A_1 2 0.1 0.1
2 B_1 2 0.1 0.1
2 B_2 2 0.1 0.1
"""
# Load data into DataFrame
df = pd.read_csv(io.StringIO(data), sep="\t")
# Transform data
df = df.sort_values(["position","frame","play_id"])
df = df.set_index(["position","frame","play_id"])
df = df.stack()
df = df.reindex(df.index.set_names(["position","frame","play_id","coord"])).unstack([0,1,3])
# Print output
print(df)
Note that I used the io.StringIO() function to load the sample data as a string. In your actual code, you can replace this with the correct way to load your data into a DataFrame.
Last modified on 2024-03-09