如何捕捉整数(0)? [英] How to catch integer(0)?

问题描述

假设我们有一个产生 integer(0) 的语句，例如

Let's say we have a statement that produces integer(0), e.g.

 a <- which(1:3 == 5)

捕捉这个最安全的方法是什么?

What is the safest way of catching this?

推荐答案

这是 R 打印零长度向量(整数 1)的方式，因此您可以测试 a 的长度是否为 0:

That is R's way of printing a zero length vector (an integer one), so you could test for a being of length 0:

R> length(a)
[1] 0

可能值得重新考虑您用于确定哪些元素所需的策略，但如果没有进一步的具体细节，则很难提出替代策略.

It might be worth rethinking the strategy you are using to identify which elements you want, but without further specific details it is difficult to suggest an alternative strategy.

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