Working with Files & Data

Read and write text files, CSV, and JSON — and process text with Python's string methods.

Beginner

3 hours

4 lessons

Course Content

20 chapters across 4 lessons

Reading & Writing Files

Open, read, and write text files from Python

5 chapters

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Why Files Matter

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Understand why programs need to read and write files

Opening & Reading Files

Use open(), with, .read(), and .readlines() to read text files

Writing to Files

Use write mode and append mode to save data to files

File Paths

Build file paths with os.path.join() for cross-platform compatibility

Mini Project: Log Writer

Build a log writer that appends timestamped entries to a file

Working with CSV

Parse and create structured tabular data with the csv module

5 chapters

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What is CSV?

Understand the CSV format and when to use it

Reading CSV

Use csv.reader and csv.DictReader to read CSV files

Writing CSV

Use csv.writer and csv.DictWriter to create CSV files

Filtering & Transforming Rows

Read CSV data, filter rows by condition, and write the results

Mini Project: Sales Report

Read a sales CSV, compute totals, and write a summary report

Working with JSON

Parse and create nested structured data with the json module

5 chapters

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What is JSON?

Understand the JSON format and how it maps to Python data structures

Reading JSON

Use json.load() and json.loads() to parse JSON data

Writing JSON

Use json.dump() and json.dumps() to save and format JSON data

Nested JSON Structures

Navigate and extract values from deeply nested JSON data

Mini Project: Config Manager

Build a config tool that reads, updates, and saves JSON settings

String Processing

Transform, search, and extract information from text

5 chapters

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String Methods

Use split(), strip(), replace(), lower(), and startswith() to transform strings

Searching in Strings

Use the in operator, .find(), and .count() to search text

Building Strings

Construct strings with .join() and f-string formatting

Parsing Structured Text

Extract data from log lines using split() and strip()

Mini Project: Text Statistics

Build a text analyzer that counts words, sentences, and top words