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Example Analysis of ChainMap Management in python

Shulou Source: shulou.com Published: 2022-06-03 15:33:59 10月16日 Update

Xiaobian to share with you the example analysis of ChainMap management in python, I hope you have gained something after reading this article, let's discuss it together!

Description:

The main use case for ChainMap is to provide an efficient way to manage multiple scopes or contexts and handle access priorities for duplicate keys.

This feature is useful when there are multiple dictionaries storing duplicate keys in the order in which they are accessed.

A classic example is found in the ChainMap documentation, which simulates how Python parses variable names in different namespaces.

When Python searches for names, it searches local, global, and built-in domains until it finds the target name. Python scopes are dictionaries that map names to objects.

To simulate Python's internal search chain, you can use chain mapping.

examples

>>> import builtins >>> # Shadow input with a global name>>> input = 42 >>> pylookup = ChainMap(locals(), globals(), vars (builtins)) >>> # Retrieve input from the global namespace>>> pylookup["input"]42 >>> # Remove input from the global namespace>>> del globals()["input"] >>> # Retrieve input from the builtins namespace>>> pylookup["input"] After reading this article, I believe you have a certain understanding of "Sample analysis of ChainMap management in python". If you want to know more about it, please pay attention to the industry information channel. Thank you for reading!

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