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,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,如何找到保存最接近此数字的数字的索引.例如,A[4] = 0.380672 最接近0.4.因此,它应该返回到4

Answer 1

我会用 which.min

which.min(abs(x-0.4))

这将返回最接近数字的第一个索引0.4.

Answer 2

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你的向量在哪里

交替,

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