从最接近给定元素的值的向量返回索引

Question

我有一个元素列表，例如

A=
  0.992688
  0.892195
  0.889151
  0.380672
  0.180576
  0.685028
  0.58195

给定一个输入元素(如0.4)，我如何找到使该数字最接近该数字的索引。例如，A[4] = 0.380672最接近0.4。因此，它应该返回到4

Answer 1

单程:

# as mnel points out in his answer, the difference,
# using `which` here gives all indices that match
which(abs(x-0.4) == min(abs(x-0.4)))

x是您的向量。

交替，

# this one returns the first index, but is SLOW
sort(abs(x-0.4), index.return=T)$ix[1]