Work with real shapes of data / CORE PATH
Exceptions & honest failures
Expected input problems need useful error messages and a visible policy.
Route invalid landing records to quarantine, as you would in a documented ETL contract.
Understand the idea
Expected input problems need useful error messages and a visible policy. Route invalid landing records to quarantine, as you would in a documented ETL contract.
Work through the practice with a tiny fixture, predict the result before running it, and record one boundary case. Use the exit check as evidence before moving on.
What to learn
- Distinguish syntax errors, exceptions and incorrect results.
- Catch narrow exceptions near the input boundary.
- Preserve a rejected record and its reason; never silently invent a value.
A small original example
try:
count = int("invalid")
except ValueError as exc:
print(f"Rejected count: {exc}")Practice on your own data
Task 12: parse a nonnegative integer count; reject blanks, decimals, negatives and booleans.
Practice this lesson in the Python lab →
"12" → 12; "12.5", "", -1 and True raise ValueError.
Common pitfalls
- An exception is not evidence that the data should be filled with zero.
- Do not expose API keys or complete sensitive payloads in logs.
Prerequisites
Boot.dev chapter 12 · 06:37:27 ↗
Video and playlist companions
Choose one explanation for the concept, then attempt the practice. These are topic mappings, not a claim that every linked lesson covers every outcome.
Boot.dev · Python for Beginners
Loads YouTube on request. Open on YouTube ↗ if the owner restricts embedding.
كورس Python منحة ITI
Loads YouTube on request. Open on YouTube ↗ if the owner restricts embedding.
Sources and further reading
- Boot.dev · Python for Beginners ↗User-selected YouTube course
- كورس Python منحة ITI ↗User-selected ITI playlist
- Harvard CS50P · lectures & problem sets ↗User-selected HarvardX CS50P course
- Python language tutorial ↗Official documentation
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