---
id: practical-python-4.4
source_exercise_id: "4.4"
title: "Using your class"
section: "4.1 Classes"
source_path: "04_Classes_objects/01_Class.md"
source_repo: "https://github.com/dabeaz-course/practical-python"
source_commit: "93dca856b41c61a0a0f85ae334116e4c125629ea"
student_visible_solution: false
has_private_solution: true
skip: false
---

# Exercise 4.4: Using your class

> Source: Practical Python Programming, `04_Classes_objects/01_Class.md`.

### Exercise 4.4: Using your class

Modify the `read_portfolio()` function in the `report.py` program so
that it reads a portfolio into a list of `Stock` instances as just
shown in Exercise 4.3.  Once you have done that, fix all of the code
in `report.py` and `pcost.py` so that it works with `Stock` instances
instead of dictionaries.

Hint: You should not have to make major changes to the code.  You will mainly
be changing dictionary access such as `s['shares']` into `s.shares`.

You should be able to run your functions the same as before:

```python
>>> import pcost
>>> pcost.portfolio_cost('Data/portfolio.csv')
44671.15
>>> import report
>>> report.portfolio_report('Data/portfolio.csv', 'Data/prices.csv')
      Name     Shares      Price     Change
---------- ---------- ---------- ----------
        AA        100       9.22     -22.98
       IBM         50     106.28      15.18
       CAT        150      35.46     -47.98
      MSFT        200      20.89     -30.34
        GE         95      13.48     -26.89
      MSFT         50      20.89     -44.21
       IBM        100     106.28      35.84
>>>
```

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## 关联来源

- [[summaries/01_Class]]