August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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22
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创建附加数据
数据准备的挑战往往在于清理和删除数据的列或行，但这样做并不总是必要的。在
为分析准备数据集时，经常需要通过某些技术来创建额外的数据。本章将分析可能
需要或不需要创建数据的情况，然后将介绍
Prep
中的各种数据创建技术。
22.1
何时不要去创建数据
数据准备的目的是减少数据分析过程中所需要的大量操作。因此，在数据准备过程
中，任何可以简化分析“数据工作”的事情都是值得去做的。例如，需要创建一些
不在数据集中，但应该用于你的分析的列或行。有多种技术可以做到这一点，但首
先让我们探讨一下在哪些地方不应该创建额外的列或行数据。
22.1.1 Tableau Desktop
中的动态计算
Tableau Desktop
的设计使我们能够以思维的速度进行分析，也就是说，在想到什么
问题的时候能尽快提供答案。这种设计部分体现在三种类型的计算上，当在屏幕上
建立分析模型时，这些计算会影响相关的数据字段。
字段计算
Tableau Desktop
根据视图中呈现的维度来计算视图中使用的度量。比如，创建
一个总销售额的计算——
sum(Sales)
，如果视图中没有该维度，
Tableau Desktop
将返回整个数据集的总销售额。如果视图中存在维度，例如，一个叫作
Product
（产
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22
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品）的维度， ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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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.