Python日常学习杂记

Python日常学习杂记

• python -c 的作用

在命令行里执行python时，如果加上 -c，即

python -c xxx

那么，xxx就被当做一条指令（command）来执行，否则，就当做脚本路径，去找script，然后执行里面的内容。比如：

$ python 'import this'
/root/anaconda3/bin/python3.7: can't open file 'import this': [Errno 2] No such file or directory

这里就把这个string作为路径去找了，没有找到文件。如果加上-c的话，就当做一条python命令执行了。

$ python -c 'import this'
The Zen of Python, by Tim Peters

Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren't special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one-- and preferably only one --obvious way to do it.
Although that way may not be obvious at first unless you're Dutch.
Now is better than never.
Although never is often better than *right* now.
If the implementation is hard to explain, it's a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea -- let's do more of those!

2019-08-14 16:20:00

• autopep8自动代码格式修改工具

链接：https://pypi.org/project/autopep8/

PEP8是Python的编码规范。https://www.python.org/dev/peps/pep-0008/

利用autopep8，可以自动将Python脚本整理成符合PEP8规范。

用法

autopep8 --in-place -r  --aggressive 文件夹名

options列表如下：

usage: autopep8 [-h] [--version] [-v] [-d] [-i] [--global-config filename]
                [--ignore-local-config] [-r] [-j n] [-p n] [-a]
                [--experimental] [--exclude globs] [--list-fixes]
                [--ignore errors] [--select errors] [--max-line-length n]
                [--line-range line line] [--hang-closing] [--exit-code]
                [files [files ...]]

Automatically formats Python code to conform to the PEP 8 style guide.

positional arguments:
  files                 files to format or '-' for standard in

optional arguments:
  -h, --help            show this help message and exit
  --version             show program's version number and exit
  -v, --verbose         print verbose messages; multiple -v result in more
                        verbose messages
  -d, --diff            print the diff for the fixed source
  -i, --in-place        make changes to files in place
  --global-config filename
                        path to a global pep8 config file; if this file does
                        not exist then this is ignored (default:
                        ~/.config/pep8)
  --ignore-local-config
                        don't look for and apply local config files; if not
                        passed, defaults are updated with any config files in
                        the project's root directory
  -r, --recursive       run recursively over directories; must be used with
                        --in-place or --diff
  -j n, --jobs n        number of parallel jobs; match CPU count if value is
                        less than 1
  -p n, --pep8-passes n
                        maximum number of additional pep8 passes (default:
                        infinite)
  -a, --aggressive      enable non-whitespace changes; multiple -a result in
                        more aggressive changes
  --experimental        enable experimental fixes
  --exclude globs       exclude file/directory names that match these comma-
                        separated globs
  --list-fixes          list codes for fixes; used by --ignore and --select
  --ignore errors       do not fix these errors/warnings (default:
                        E226,E24,W50,W690)
  --select errors       fix only these errors/warnings (e.g. E4,W)
  --max-line-length n   set maximum allowed line length (default: 79)
  --line-range line line, --range line line
                        only fix errors found within this inclusive range of
                        line numbers (e.g. 1 99); line numbers are indexed at
                        1
  --hang-closing        hang-closing option passed to pycodestyle
  --exit-code           change to behavior of exit code. default behavior of
                        return value, 0 is no differences, 1 is error exit.
                        return 2 when add this option. 2 is exists
                        differences.

2019-08-26 10:45:14

• 为文件名添加时间

import datetime
jetzt = str(datetime.date.today())
print(jetzt)

>>> 2019-08-28

可以将日期附到文件名中，便于日后根据时间查找。

2019-08-28 11:24:06