- Python : 3.7.3
- OS: Ubuntu 18.04.2 LTS
- IDE : pycharm-community-2019.1.3
- Conda: 4.7.5
- typesetting : Markdown
code
coder@ubuntu:~$ conda activate py37
(py37) coder@ubuntu:~$ ipython
Python 3.7.3 (default, Mar 27 2019, 22:11:17)
Type 'copyright', 'credits' or 'license' for more information
IPython 7.5.0 -- An enhanced Interactive Python. Type '?' for help.
In [1]: my_str = "0123456789"
In [2]: "前三个字符", my_str[:3]
Out[2]: ('前三个字符', '012')
In [3]: "后三个字符,倒序", my_str[-1:-4:-1]
Out[3]: ('后三个字符,倒序', '987')
In [4]: "后三个字符,正序", my_str[-3:]
Out[4]: ('后三个字符,正序', '789')
In [5]: start_index, end_index, step = 1, 7, 2
In [6]: my_str[start_index: end_index: step]
Out[6]: '135'
In [7]: # 反向提取
In [8]: # 字符串最后一个字符的索引也是 -1，倒数第二个字符的索引是-2
In [9]: start_index, end_index, step = -1, -5, -1
In [10]: # -1 -2 -3 -4
In [11]: my_str[start_index: end_index: step]
Out[11]: '9876'
In [12]: exit
(py37) coder@ubuntu:~$ conda deactivate
coder@ubuntu:~$
resource
- [Documents - English] docs.python.org/3
- [Documentation - Chinese] docs.python.org/zh-cn/3
- [Specification] www.python.org/dev/peps/pep-0008
- [Specification] zh-google-styleguide.readthedocs.io/en/latest/google-python-styleguide/python_language_rules
- [Source] www.python.org/downloads/source
- [ PEP ] www.python.org/dev/peps
- [Platform] www.cnblogs.com
- [Platform] gitee.com
Python has an open source, cross-platform, interpreted, interactive and other characteristics, it is worth learning.
Python's design philosophy: elegant, clear and simple. Promote the use of a method, the best is only one way to do a thing.
Writing code to comply with norms, which helps communication and understanding.
Each language has unique ideas, beginners need to change the thinking, pragmatic practice, adhere to accumulate.