Back to PANDAS FOR DATA ANALYTICS

Reading & Writing Data

Understand how to import and export CSV, Excel, and JSON files using pandas—your first step into real datasets.

33 minutesVideo LessonPDF notes
🎯 Free Guest Mode: You are learning for free. Sign in to save your completion progress and quiz answers.

Ready to continue?

Mark this lesson as complete when you're ready to proceed.

Key moments

  1. CSV Read and Write — The standard methods `read_csv` and `to_csv` are demonstrated, including setting the index column upon import.
  2. Tab-Delimited Files — Tab-delimited files are handled by passing the custom separator `sep='\t'` to the standard CSV methods.
  3. Excel Dependencies — External packages like `openpyxl`, `xlwt`, and `xlrd` must be installed to enable Excel file interaction.
  4. Excel I/O Methods — The dedicated methods `to_excel` and `read_excel` are used to export and import data from XLSX files.
  5. Default JSON Export — The `to_json` method is introduced, which defaults to a dictionary-like orientation where columns are keys.
  6. JSON Orientation Control — Using `orient='records'` and `lines=True` creates a list-like JSON structure that is often easier to read and process.
PDF notes

Frequently asked questions

Why do I need to install extra packages for Excel but not CSV?

CSV is a simple text format that Pandas handles natively, but Excel files are complex binary formats requiring specialized libraries like `openpyxl` to parse and generate.

How do I read a file that uses a semicolon (;) instead of a comma?

Use the `sep` argument in `pd.read_csv()`, setting it to the custom delimiter, e.g., `sep=';'`.

What is the difference between the default JSON orientation and `orient='records'`?

Default (dictionary-like) groups data by column; `orient='records'` groups data by row, making it list-like and often easier for line-by-line processing.

How was this lesson?

Your feedback helps us refine explanations and catch bugs.