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Visitor mode is to encapsulate some operations applied to a certain data structure. Once these operations need to be modified, the data structure that accepts this operation can be saved unchanged. Visitor mode is suitable for systems with relatively stable data structures. It reduces the coupling degree between data structures and operations acting on data structures, making the set of operations relatively free to change. The specific structure diagram is as follows:EXAMPLE 4Use Python for data analysis: This book is a detailed version of Python's pandas package. Learn this to master some basic pandas commands. However, this is not the point, because pandas is too slow to produce a large amount of data and may collapse (I don't know if there is any improvement now-!) The point is, through studying this book, I feel a little about the data operation and am familiar with the basic data operation process. All the operations in this book can be replaced by native Python, and Pandas package is not needed. Finding feelings is very important.The following is a specific diagram and how to kill.It is best not to win against team C, because once you win, you will play against team C in case you win again.依我说，咱们这一块，除了你们小女娃，就数黄瓜表弟迷人。两年前，当红女演员舒星因参加一场晚宴被陷害杀人，舆论瞬间倾倒，她跌落深渊。蛰伏两年，她霸气复出，发誓一定要找回当年的真相，让所有做过错事的人都受到惩罚！随着计划展开，凌云、光月、苏雨、莫莉等人隐藏的秘密逐渐浮现，前男友顾晨和现男友景明也被卷入其中.......面对乱象丛生的复杂情感，众人会如何完成自己的救赎？