Tirsvad
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Six pages and a sidebar, each lecture step with its screenshot and what it taught; review record RC-008. Refs #14 Refs #15 Refs #16 Refs #17 Refs #18
25 lines
1.0 KiB
Markdown
25 lines
1.0 KiB
Markdown
# Step 3: the timing wrapper
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**English** · [Dansk](Step-3-Timing-Wrapper-da) · [Bahasa Malaysia](Step-3-Timing-Wrapper-ms)
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The wrapper reads the clock before and after the call and prints the difference:
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```python
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start = clock()
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result = function(*args, **kwargs)
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seconds = clock() - start
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output(RESULT_TEMPLATE.format(name=function.__name__, seconds=seconds))
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return result
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```
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Run it with `python -m speed_calc.lecture_steps 3`.
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## What we gained
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- A decorator can run code before and after the function without changing the function.
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- The wrapper returns the function's result, so the decorated function still works as before.
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- `make_speed_calc_decorator(clock, output)` takes the clock and the output as parameters. The tests give it a fake clock, so they check exact values and never wait for real time.
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- The text format lives in `constants.py`, the one place for constants.
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