- 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:~$ source 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]: a = [{}] * 3
In [2]: a
Out[2]: [{}, {}, {}]
In [3]: id(a[0]), id(a[1]), id(a[2])
Out[3]: (140086817892752, 140086817892752, 140086817892752)
In [4]: a[0]["lang"] = "python" # 看到这里我明白了,那个乘号扩展的是引用、标记,只有一个dict对象。再做一下测试。
In [5]: a
Out[5]: [{'lang': 'python'}, {'lang': 'python'}, {'lang': 'python'}]
In [6]: exit
(py37) coder@ubuntu:~$ conda deactivate
coder@ubuntu:~$
more_knowledge
coder@ubuntu:~$ source 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]: a = []
In [2]: a.append(dict())
In [3]: a.append(dict())
In [4]: a
Out[4]: [{}, {}]
In [5]: id(a[0]), id(a[1])
Out[5]: (140174650278320, 140174650281416)
In [6]: # 难道只能按照csdn的u011550708博主所说的"必须要对每个dict单独定义",还有更好的办法吗?有待学习.
In [7]: # 感谢前辈的经验贴,后生学习了!
In [8]: exit
(py37) coder@ubuntu:~$ conda deactivate
coder@ubuntu:~$
reference
resource
- [文档 - English] docs.python.org/3
- [文档 - 中文] docs.python.org/zh-cn/3
- [规范] www.python.org/dev/peps/pep-0008
- [规范] zh-google-styleguide.readthedocs.io/en/latest/google-python-styleguide/python_language_rules
- [源码] www.python.org/downloads/source
- [ PEP ] www.python.org/dev/peps
- [平台] www.cnblogs.com
- [平台] gitee.com
Python具有开源、跨平台、解释型、交互式等特性,值得学习。
Python的设计哲学:优雅,明确,简单。提倡用一种方法,最好是只有一种方法来做一件事。
代码的书写要遵守规范,这样有助于沟通和理解。
每种语言都有独特的思想,初学者需要转变思维、踏实践行、坚持积累。