August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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.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.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.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.
｜
251
使用数据角色
Tableau
开发人员通过
data roles
（数据角色）为数据清理增加了额外的验证级别。
对于字符串数据字段，现在可以为
Tableau Prep
设置一个特定的数据角色来测试数
据。你可以根据
Tableau
自己的列表测试地理角色、电子邮件地址和
URL
，看看它
们是否有效。
28.1
如何使用数据角色
当点击数据类型图标来改变数据类型时，可看到一个下拉的选项列表（见图
28-
2
）。在本例中，我正在指定
City
（城市）角色。
图
28
-
2
：在 Tableau Prep 中设置数据角色，在本例中指定了 City（城市）角色
通过选择
City
（城市）来比较
Preppin' Data 2019
：第
2
周挑战赛中的城市名称列表，
可以看到哪些数据
Prep
将其识别为真正的城市名称，哪些未识别（见图
28-3
）。
有了这里突出显示的内容，就可以使用
Prep
的神奇的分组和替换功能轻松解决所有
问题。
252
｜
第
28
章
图
28
-
3
：将 City（城市）数据角色应用于城市字段的结果
但如果你想去除这些错误呢？好吧，通过使用一个有效的数据角色，实际上你可以
采取其他的几个方法来实现（见图
28-4
）。
图
28
-
4
：控制应用数据角色后返回的数据
你可以选择是否要查看：
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
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.