August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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93
第
11
章
数据概要分析
数据准备的艺术是理解数据集，以确定你可能需要做什么准备来进行分析。了解数
据的概况是形成数据全貌的关键。如果不对数据进行概要分析，则很容易错过一个
明显的准备步骤或增加不必要的工作。本章将探讨什么是概要分析，为什么数据概
要分析很重要，以及
Prep
如何对数据进行概要分析。
11.1
什么是数据概况
所谓数据概况，是指数据集的特征。正如前面几章所讨论的那样，了解数据集中的
数据类型对分析至关重要。同样重要的是了解数据集的分类数据字段的数量和方差。
确定数据集的粒度级别将有助于确定有多少唯一的记录，或者是否有需要在数据准
备过程中删除的重复记录。所有这些因素构成了数据集概况的基础，它包括以下这
些因素：
•
最小值、最大值和数值范围：最小值和最大值之间的范围是否合理？
•
边界值之外的数据：数据中是否存在自然限制，比如
100%
，或者当前日期不能
超过但已经超过了？
•
异常值：除了一个或几个超出范围的值外，这些值是否在一定范围内？
•
不合规的记录数：某些维度的行数是否一致，这个数字是否会突然改变？例如，
你是否希望数据集中的每个日期都有固定的记录数？
•
拼写不规范：能确定数据集中的名称和单词的正确拼写吗？
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