Python3基础 list(dict) 使用 * 扩充时,出现字典元素重复问题

  • 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。
每种语言都有自己独特的思维,初学者需要转变思维、练习思维、坚持积累。

[En]

Each language has its own unique thinking, and beginners need to change their thinking, practice it and persist in accumulation.

Original: https://www.cnblogs.com/xingchuxin/p/11144138.html
Author: 行初心
Title: Python3基础 list(dict) 使用 * 扩充时,出现字典元素重复问题

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