3.29.5 使用signum做选择 Using signum to make a choice 实用的小精灵（Gremlin图查询语言） 阿岶奇TinkerPop向导 PRACTICAL GREMLIN An Apache TinkerPop Tutorial

正负号函数signum运算符允许我们依照一个数字的值是正数，负数还是0.返回1，-1或者0

The signum operator allows us to make a decision depending upon whether a numeric value is

positive, negative or zero as shown below.

 

我们可以使用这一能力来构建一个查询报告机场所在的位置在格林威治子午线的哪边。注意我们在option步骤的数字前用到了D前缀因为返回是一个双精度的结果。

We can use this capability to build a query that reports which side of the Greenwich meridian an

airport is located. Note that I had to use the "D" suffix on the numbers in the option steps as math

returns a double precision result.

 

 

这是运行查询得到的输出。

Here is an example of the output from running the query.