为什么all.equal（1,2,3）返回TRUE

Question

I tried all.equal(1,2) and it returned a mean difference of 1.

Why does all.equal(1,2,3) show TRUE ?

Is it because if it is supplied more than two variables it runs is.numeric() on its different elements to check their type instead of numerical differences?

Answer 1

Because 1 is equal to 2 within a tolerance of 3. From the docs:

  target: R object.

 current: other R object, to be compared with ‘target’.

     ...: Further arguments for different methods, notably the
          following two, for numerical comparison:

tolerance: numeric >= 0.  Differences smaller than ‘tolerance’ are not
          reported.  The default value is close to ‘1.5e-8’.

Your 3 is the third argument, and so becomes the tolerance.