August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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266
第
30
章
去除重复数据
了解数据的颗粒度水平是为分析做好准备的关键。然而，在研究粒度问题时，你可
能会发现一些不清晰的答案。造成这种不清晰的原因往往是重复数据。本章将介绍
如何识别数据集中的重复数据，以及你可以对它们做些什么。
30.1
如何识别重复的数据
除非你是故意寻找重复的数据，否则就是在依靠“了解数字”的人告知你有问题。
因此，重要的是，你要积极主动地去尝试避免数据集中的重复数据，并在需要时知
道如何删除它们。去除重复的数据使数据汇总变得更容易，因为你可以简单地对记
录进行求和，从而找到总数，这反过来又使得到的数据集更容易进行分析。
让我们看一个例子，当订单进入
Chin & Beard Suds Co.
公司时的情况。在分析订单
时，我们希望有一个数据集，每个订单有自己的行。当把数据集加载到
Prep Builder
中时，你可以很容易地确定：
•
每张订单有多少行（这里用
Case ID
表示）。
•
是否如概况窗格中显示的那样，行数分布均匀。
点击单个
Case ID
，可以在数据窗格中看到每个
ID
有多行，不同的
ID
在数据集中
的行数不同（见图
30-1
）。
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.