August 2022
Beginner to intermediate
463 pages
9h 22m
Chinese
Content preview from Tableau Prep即学即用
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158
｜
第
18
章
18.3
计算的基础知识
图
18-2
和图
18-3
所示的计算窗口中包含了几个真正能帮助你学习并最终掌握计算
的元素。
18.3.1
参考列表
第一个要素是右侧的下拉式
Reference
（参考）列表。如果你是数据工具行业的计算
新手，这个列表对寻找最佳函数以获得所需答案有巨大帮助（见图
18-5
）。输入一
个函数，就能告诉
Prep Builder
要对数据字段进行什么操作。
图
18
-
5
：对计算函数进行分组从而使搜索变得更容易
在参考列表的右边是计算窗口中支持的第二个要素：在参考列表中所选择的函数的
语法、描述和示例。图
18-6
展示了
DATEPART()
函数的这些信息，该函数用于选取
给定日期中的部分数据内容。
让我们来看看每条信息的详细情况。
｜
159
计算
图
18
-
6
：计算函数的详细情况
18.3.2
语法
即使是一个有经验的
Tableau
或数据软件用户，也会经常需要检查函数的语法以及
函数工作所需的数据类型，以达到预期的目的。下面的内容是关于如何理解语法的：
FUNCTION
(
required input
, [
optional input
])
在调用函数时，需要记住，你必须匹配语法中没有放在方括号内的所有方面，它们
不是可选的。这些要求可能包括必要的数据类型，或数据字段是否被汇总。函数中
的方括号表示可选内容。 ...
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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.
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.