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https://github.com/huidaecho/cjkformat

This Python 3 module provides utility functions for formatting fixed-width CJK strings.
https://github.com/huidaecho/cjkformat

cjk formatter formatting python3

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This Python 3 module provides utility functions for formatting fixed-width CJK strings.

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README 

        
# CJK Format



This Python 3 module provides utility functions for formatting fixed-width CJK strings. Functionally, it is similar to the [libaprintf](https://github.com/HuidaeCho/libaprintf) (aligned printf) C library.



[파이썬 3에서 한글 print 포맷 정렬하기](https://geni.isnew.info/%ED%8C%8C%EC%9D%B4%EC%8D%AC-3%EC%97%90%EC%84%9C-%ED%95%9C%EA%B8%80-print-%ED%8F%AC%EB%A7%B7-%EC%A0%95%EB%A0%AC%ED%95%98%EA%B8%B0.html)



## Installation



This module is published in [PyPI](https://pypi.org/project/cjkformat/), so you can install it using `pip3`:

```bash

pip3 install --user cjkformat

```



Yeah, 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!



## Introduction



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

```python

print('%-10s|%-10s|' % ('ab', 'cd'))

print('%-10s|%-10s|' % ('가나다라', '마바사아'))

```

to produce



![Aligned output](aligned.png "Aligned output")



because both lines use the same-width string specifiers (`%10s`). However, this code snippet will produce



![Misaligned output](misaligned.png "Misaligned output")



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:

```python

print('%-10s|%-10s|' % ('ab', 'cd'))

print('%-6s|%-6s|' % ('가나다라', '마바사아'))

```

which will print nicely aligned



![Aligned output](aligned.png "Aligned output")



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](https://pypi.org/project/cjkstr/)

* [Python unicodedata.east_asian_width() Examples](https://www.programcreek.com/python/example/5938/unicodedata.east_asian_width) and

* [파이썬(Python)으로 한글 print format 설정 시 padding이 잘 맞지 않을 때](https://sarc.io/development/810-python-print-format-padding),



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

```python

from cjkformat import f



print(f('%-10s|%-10s|', 'ab', 'cd'))

print(f('%-10s|%-10s|', '가나다라', '마바사아'))

```

which will print



![Aligned output](aligned.png "Aligned output")



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()`,

```python

from cjkformat import printf



printf('%-10s|%-10s|\n', 'ab', 'cd')

printf('%-10s|%-10s|\n', '가나다라', '마바사아')

```

will produce the same output:



![Aligned output](aligned.png "Aligned output")



## License



Copyright (C) 2020, Huidae Cho <>



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 <>.