This Python 3 module provides utility functions for formatting fixed-width CJK strings. Functionally, it is similar to the libaprintf (aligned printf) C library.
This module is published in PyPI, so you can install it using pip3:
pip3 install --user cjkformatYeah, there is no version 0.1.0 there. I had to make a small fix, but I didn't know that the same version is never allowed again even after the project is deleted. I see one typo there in README.md, but who cares!
One of the most important features of this module is to align Latin and CJK characters using %{width}s specifiers. For example, you may expect the following lines
print('%-10s|%-10s|' % ('ab', 'cd'))
print('%-10s|%-10s|' % ('가나다라', '마바사아'))to produce
because both lines use the same-width string specifiers (%10s). However, this code snippet will produce
even though the pipe characters are vertically (horizontally?) aligned between the two print lines. This misalignment occurs because wide CJK characters are considered one character (e.g, len('가')=1) even though they take up two column spaces. To resolve this alignment issue, the width component of the string specifier needs to be adjusted using the number of actual CJK characters in the argument string. The above example can be fixed by reducing the width 10 to 10 - 4 (four CJK characters in each %10s) as follows:
print('%-10s|%-10s|' % ('ab', 'cd'))
print('%-6s|%-6s|' % ('가나다라', '마바사아'))which will print nicely aligned
However, it would be very cumbersome to count CJK characters and adjust widths in the format string every time we use CJK characters. I found some solutions from these articles:
- CJKStr -- A Simple Package for Processing CJK string
- Python unicodedata.east_asian_width() Examples and
- 파이썬(Python)으로 한글 print format 설정 시 padding이 잘 맞지 않을 때,
but I was not happy with any of those solutions because they deviated too much from the usage of print() and disrupt regular patterns of print(). It would also be hard to justify use of those functions to non-CJK developers when they have very different calling patterns.
In this module, I tried to mimic the usage of print() as much as possible. Since the % operator is interpreted first before being passed to any functions, I was not able to use exactly the same syntax as print(). Instead, I tried to keep the name of the core function short and simple. Indeed, its name is simply f, which is the same as the prefix for the f-string syntax. I also defined printf() that behaves much like the printf() function in the C language. This function combines print(, end='') and f() to not add a newline.
Now, using the new f() function, the above example would be
from cjkformat import f
print(f('%-10s|%-10s|', 'ab', 'cd'))
print(f('%-10s|%-10s|', '가나다라', '마바사아'))which will print
Note that the f() function takes both the format and arguments. Also, unlike print(), it takes a variable number of arguments instead of a list of arguments.
Equivalently, using printf(),
from cjkformat import printf
printf('%-10s|%-10s|\n', 'ab', 'cd')
printf('%-10s|%-10s|\n', '가나다라', '마바사아')will produce the same output:
Copyright (C) 2020, Huidae Cho <https://idea.isnew.info>
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.