Sample DataFrame context
Grouped data with multiple index levels.
Syntax or pattern
df.set_index(["region","month"]).unstack()5 practical examples
Start from a clean copy
Create a copy before changing the original data.
work = df.copy()You can test the workflow without overwriting the source DataFrame.
Apply the main pattern
Use the pandas pattern for the main task.
# Example pattern
result = workThe result stores the transformed data.
Check the output shape
Confirm row and column counts after the step.
result.shapeThis helps catch unexpected row loss or duplication.
Preview the result
Inspect the first rows before exporting.
result.head()A quick preview confirms columns and values look right.
Export the final table
Save the output for sharing or dashboard use.
result.to_csv("output.csv", index=False)The final result can be used outside Python.
Common mistakes to avoid
- Changing the original DataFrame before checking the result.
- Forgetting to inspect row counts before and after the operation.
- Using a pattern without confirming column names and data types.
FAQ
What is the main use of stack and unstack Examples?
Reshape MultiIndex data between long and wide formats.
Should I use this in a notebook or a script?
Both work. Use a notebook while exploring the data, then move the final workflow into a repeatable script when it is stable.
How do I avoid breaking my source data?
Create a copy of the DataFrame before transforming it and check row counts, missing values and sample rows after each important step.