coding-mentor-agent/kb/python-course-kb-practical-python/wiki/exercises/6-6-using-a-generator-to-produce-data.md

id, source_exercise_id, title, section, source_path, source_repo, source_commit, student_visible_solution, has_private_solution, skip

id	source_exercise_id	title	section	source_path	source_repo	source_commit	student_visible_solution	has_private_solution	skip
practical-python-6.6	6.6	Using a generator to produce data	6.2 Customizing Iteration	06_Generators/02_Customizing_iteration.md	https://github.com/dabeaz-course/practical-python	93dca856b41c61a0a0f85ae334116e4c125629ea	false	false	false

Exercise 6.6: Using a generator to produce data

Source: Practical Python Programming, 06_Generators/02_Customizing_iteration.md.

Exercise 6.6: Using a generator to produce data

If you look at the code in Exercise 6.5, the first part of the code is producing lines of data whereas the statements at the end of the while loop are consuming the data. A major feature of generator functions is that you can move all of the data production code into a reusable function.

Modify the code in Exercise 6.5 so that the file-reading is performed by a generator function follow(filename). Make it so the following code works:

>>> for line in follow('Data/stocklog.csv'):
          print(line, end='')

... Should see lines of output produced here ...

Modify the stock ticker code so that it looks like this:

if __name__ == '__main__':
    for line in follow('Data/stocklog.csv'):
        fields = line.split(',')
        name = fields[0].strip('"')
        price = float(fields[1])
        change = float(fields[4])
        if change < 0:
            print(f'{name:>10s} {price:>10.2f} {change:>10.2f}')

关联来源

• summaries/02_Customizing_iteration