August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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376
｜
第
41
章
•
计算中使用的列已被重命名。
所有这些改变都可能导致
Prep Builder
返回一个空白的概况窗格，因为不可能加载
数据，或者数据字段将在清理步骤中只有
null
（空值）或
blank
（空白）值（见图
41-5
）。
图
41
-
5
：错误导致的空白清理步骤
41.3
计算字段内的错误
在
Prep Builder
中发生错误时，它们可能不会像刚才所出现的情况那样丢失所有数
据或造成灾难性的后果。计算字段错误是最常犯的错误，但一般来说，如果知道如
何发现它们，就很容易修复。
41.3.1
不完整的计算
在编写计算时，能很快看到计算的格式不符合
Prep Builder
所期望的格式。例如，
图
41-6
中的计算出错是因为
IF
语句还没有
END
条件。
｜
377
处理
Prep Builder
错误
图
41
-
6
：由于计算不符合要求的语法而导致的错误
通过点击
Calculation Editor
（计算编辑器）底部的
1 error
（
1
个错误）旁的箭头，
可以马上看到计算中缺少的内容。在建立
IF
语句时，我经常提前添加
END
条件，然
后在
IF
和
END
两个词之间编辑计算过程，这样随着错误的消失，我就可以看到每个
条件是何时完成的（见图
41-7
）。
图
41
-
7
：Prep Builder 中的非错误计算
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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.