August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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322
｜
第
35
章
35.5
做好迭代准备
通常情况下，只有“与数据一起工作”才能得出解决方案。否则，很难想象数据在
每个步骤中以及在你进行分析过程中使用数据时究竟会有怎样的表现。在分析数据
时，你可能会决定需要进一步迭代或删除某些步骤。这是件好事——这都是学习数
据准备经验的一部分，幸运的是，有了
Prep Builder
，你可以快速做出这些改变。
例如，在创建
Win(W
，胜
)
、
Loses(L
，负
)
、
Home Results(Home
，主场成绩
)
和
Away Results(Away
，客场成绩
)
列时，我知道它们会涉及类似的计算，但不确定以
何种顺序处理它们。这些列代表了总的胜负以及主客场比赛中取得的胜负记录。图
35-14
展示了我用来处理这项任务的流程。
图
35
-
14
：创建胜、负、主场成绩和客场成绩列的流程
我需要的每支球队的主要数据点是球队在比赛中是赢了还是输了。我已经掌握了处
于比赛热门的球队是否比对手得分多。如果他们得分更多，我就返回一列
W
；否则，
我就返回一列
L
。这种逻辑是正确的，但对于汇总计算所有相关的胜负总和来说并
不理想。因此，我将这一列进行了转换，为两者创建了一个单列。
为了使接下来的计数变得简单，我创建了一个简单的计算方法，即根据结果将
1
加
到每个胜负列中（见图
35-15
）。
已经知道了接下来的步骤需要一个汇总操作，我意识到此时需要把这个过程分成两
个流程。汇总步骤只返回汇总值和分组数据字段（关于
Prep
中汇总步骤的内容，请
阅读第
15
章）。即使有非常仔细的规划，我也不可能预料到此时会在流程中增加另 ...
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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.