使用比较器语法进行常规排序 [英] groovy sort with comparator syntax

问题描述

我刚刚被小鬼弄湿了.我知道 gremlin 是基于 groovy 的.我在这里找到了文档a>，但我仍然不确定语法是什么意思.

I am just getting my feet wet with gremlin. I understand that gremlin is based on groovy. I found the documentation here, but I am still not sure what the syntax means.

我对使用比较器的排序语法如何工作感到有些困惑:

I am a bit confused as to how the syntax of sort with a comparator works:

m.sort{a,b -> a.value <=> b.value}

有人能解释一下 { 和 } 之间的所有不同位是什么意思吗?

Could someone explain what all the different bits between the { and } mean?

推荐答案

当 sort 使用的 Closure 有两个参数时，它的作用就像传统的 Comparator.也就是说，对于在排序过程中进行的每次比较，在两个元素 a 和 b 之间，它返回一个负整数、零或一个正整数作为第一个参数小于、等于或大于第二个.

When the Closure used by sort has two parameters, it acts like a traditional Comparator. That is, for each comparison that is done during the sort, between two elements a and b, it returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

在您的特定场景中，比较是使用 太空船运算符 的结果<=>.换句话说，您可以有效地按升序顺序对元素进行排序.

In your particular scenario, the comparison is the result of using the spaceship operator <=>. In other words, you are effectively sorting your elements in ascending order.

例如，如果您有列表 [ 3, 2, 1 ]，则使用该排序的结果 应该是 [ 1, 2, 3 ].

For example, if you had the list [ 3, 2, 1 ], the result of using that sort would be [ 1, 2, 3 ].

因此，m.sort{a,b ->a.值<=>b.value} 大致相当于使用以下 compare 函数:

Thus, m.sort{a,b -> a.value <=> b.value} is roughly the equivalent of using the following compare function:

int compare(a, b) {
  if (a < b) {
    return -1;
  } else if (a > b) {
    return 1;
  } else {
    return 0;
  }
}

这篇关于使用比较器语法进行常规排序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！