> a[1-3] [1] 1 3 > a[[1-3]] Error in a[[1 - 3]] : attempt to select more than on... | Hacker News

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fxj on Aug 17, 2016 | parent | context | favorite | on: 15 Page Tutorial for R

  > a[1-3]
  [1] 1 3
  > a[[1-3]]
  Error in a[[1 - 3]] : attempt to select more than one element

The first line evaluates to a[-2]. I think what the author meant was a[1:3]. a[[-2]] gives an error, a[[2]] is valid R.

capnrefsmmat on Aug 17, 2016 [–]

a[-2] is valid R syntax. A negative index means that element is omitted from the result, so a[-2] is a without the second element.

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