coding-mentor-agent/kb/python-course-kb-practical-python/wiki/exercises/2-8-how-to-format-numbers.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-2.8	2.8	How to format numbers	2.3 Formatting	02_Working_with_data/03_Formatting.md	https://github.com/dabeaz-course/practical-python	93dca856b41c61a0a0f85ae334116e4c125629ea	false	false	false

Exercise 2.8: How to format numbers

Source: Practical Python Programming, 02_Working_with_data/03_Formatting.md.

Exercise 2.8: How to format numbers

A common problem with printing numbers is specifying the number of decimal places. One way to fix this is to use f-strings. Try these examples:

>>> value = 42863.1
>>> print(value)
42863.1
>>> print(f'{value:0.4f}')
42863.1000
>>> print(f'{value:>16.2f}')
        42863.10
>>> print(f'{value:<16.2f}')
42863.10
>>> print(f'{value:*>16,.2f}')
*******42,863.10
>>>

Full documentation on the formatting codes used f-strings can be found here. Formatting is also sometimes performed using the % operator of strings.

>>> print('%0.4f' % value)
42863.1000
>>> print('%16.2f' % value)
        42863.10
>>>

Documentation on various codes used with % can be found here.

Although it’s commonly used with print, string formatting is not tied to printing. If you want to save a formatted string. Just assign it to a variable.

>>> f = '%0.4f' % value
>>> f
'42863.1000'
>>>

关联来源

• summaries/03_Formatting