7.2Selecting data.py

# -*- coding: utf-8 -*-
"""
Created on Tue Nov 29 22:55:25 2022

@author: xuanQS
"""

"""
Although they may give the same output, 
selecting data with expressions or square bracket indexing 
are not equivalent. 
The implementation of selecting data with expressions 
is completely different from 
the implementation of selecting data 
with square bracket indexing.
即，尽管结果一致，但其实现机制并不相同
文档中建议，只有当探索数据的时候，考虑使用[]索引
否则，都强烈建议使用expressions
We strongly recommend selecting data with expressions
"""