August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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110
第
13
章
将列转为行
我是在
20
世纪
90
年代长大的，所以当我听到
pivot
（转换）这个词时，我脑海中立
刻跳出的画面，是
Friends
（老友记）中的角色们，正在试图把
Ross
的沙发搬上蜿
蜒的公寓楼梯。
我们在第
4
章中首次讨论了转换数据（不是楼梯间的沙发）。本章将在该讨论的基
础上，探讨何时以及如何在
Prep Builder
中将列数据转换为行数据。这种类型的数
据转换也被称为转置。
13.1
何时在
Tableau Prep Builder
中进行数据
转换
Tableau Desktop
需要将数据放在结构化的列中。每一列可以容纳一种类型的数据，
并且可以在
Desktop
功能区或卡片上使用，以改变屏幕上显示的视图。相应地，转换
的一个常见场景是当你要为数据集中的每个新日期添加一个新列时（见图
13-1
）。
图
13
-
1
：每个月为数据集添加新列
｜
111
将列转为行
图
13-2
中的数据结构不是很好，有两个原因。第一，如果想让日期显示在
x
时间轴
上，就不能用这个结构来做，因为你需要用一列来存放所有不同的日期，另一列来
存放每个日期的所有相关值。第二，如果文件更新了，
Tableau Desktop
不会自动将
新列添加到你的分析中。如果新数据以附加行的形式出现，反而会被包含在视图中
（只要
Desktop
能够读取它）。图
13-2 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
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.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
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.