Files and Data Formats

What you will learn

• Text and binary files
• Encodings and errno
• pathlib
• CSV
• JSON
• Context managers
• Data cleaning

Lessons

1. 1

   Reading and Writing Text Files

   Open files with the right mode, let with close them, read line by line and rewind a handle you have used up.

   11 exercises

2. 2

   Binary Files, Modes and I/O Errors

   Create files exclusively, read and write raw bytes, pick the right encoding, handle OSError and errno, and write to the standard streams.

   12 exercises

3. 3

   Paths and the File System

   Build paths with pathlib, create folders, find files with glob and handle files that are missing.

   11 exercises

4. 4

   CSV

   Read and write spreadsheet data with the csv module, convert its strings, survive quoted commas and never forget newline="".

   12 exercises

5. 5

   JSON

   Convert between Python and JSON, keep dump and dumps apart, navigate nested data, handle malformed input and teach json new types.

   12 exercises

6. 6

   Writing Your Own Context Managers

   Build your own with-statement helpers with __enter__ and __exit__ or @contextmanager, decide when errors propagate, and use suppress and redirect_stdout.

   8 exercises

7. 7

   Putting It Together

   Build real data jobs: a CSV to JSON sales summary, a two-file merge, a safe save, a rotating log, streaming a huge log and a cleaning pass with a rejects file.

   8 exercises

How you practice

You practice in the browser and every exercise gives you feedback right away. This course uses these formats:

• Code exercise: 25
• Fix the bug: 18
• Type the answer: 9
• Predict the output: 8
• Multiple choice: 4
• Fill in the blank: 4
• Select all that apply: 2
• Match the pairs: 2
• Reorder lines: 1
• Spot the bug: 1

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