coding-mentor-agent/kb/python-course-kb-practical-python/wiki/exercises/3-7-picking-a-different-column-delimiter.md

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id	source_exercise_id	title	section	source_path	source_repo	source_commit	student_visible_solution	has_private_solution	skip
practical-python-3.7	3.7	Picking a different column delimiter	3.2 More on Functions	03_Program_organization/02_More_functions.md	https://github.com/dabeaz-course/practical-python	93dca856b41c61a0a0f85ae334116e4c125629ea	false	true	false

Exercise 3.7: Picking a different column delimiter

Source: Practical Python Programming, 03_Program_organization/02_More_functions.md.

Exercise 3.7: Picking a different column delimiter

Although CSV files are pretty common, it’s also possible that you could encounter a file that uses a different column separator such as a tab or space. For example, the file Data/portfolio.dat looks like this:

name shares price
"AA" 100 32.20
"IBM" 50 91.10
"CAT" 150 83.44
"MSFT" 200 51.23
"GE" 95 40.37
"MSFT" 50 65.10
"IBM" 100 70.44

The csv.reader() function allows a different column delimiter to be given as follows:

rows = csv.reader(f, delimiter=' ')

Modify your parse_csv() function so that it also allows the delimiter to be changed.

For example:

>>> portfolio = parse_csv('Data/portfolio.dat', types=[str, int, float], delimiter=' ')
>>> portfolio
[{'name': 'AA', 'shares': 100, 'price': 32.2}, {'name': 'IBM', 'shares': 50, 'price': 91.1}, {'name': 'CAT', 'shares': 150, 'price': 83.44}, {'name': 'MSFT', 'shares': 200, 'price': 51.23}, {'name': 'GE', 'shares': 95, 'price': 40.37}, {'name': 'MSFT', 'shares': 50, 'price': 65.1}, {'name': 'IBM', 'shares': 100, 'price': 70.44}]
>>>

Commentary

If you’ve made it this far, you’ve created a nice library function that’s genuinely useful. You can use it to parse arbitrary CSV files, select out columns of interest, perform type conversions, without having to worry too much about the inner workings of files or the csv module.

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关联来源

• summaries/02_More_functions