[R] Why is options(digits = 1) displays two digits?

[Martin Maechler]

>>>>> Gerrit Eichner <Gerrit.Eichner at math.uni-giessen.de>
>>>>>     on Tue, 21 Mar 2017 10:45:13 +0100 writes:

    > Hi, Tal,
    > in print.default it says:

    > digits:

    > a non-null value for digits specifies the __minimum__
    > number of __significant__ digits to be printed in values.

    > Maybe this clarifies your observation.

    > Hth  --  Gerrit

I hope too, thank you Gerrit.

It seems that many people do not understand the term
"number of significant digits".

I think you can learn about it by studying (the help page and
examples of)
   signif(x, digits)

and maybe compare with  round (x, digits).

    > Am 21.03.2017 um 10:30 schrieb Tal Galili:
    >> This may have been asked before, but I don't understand the behavior
    >> of options(digits = 1) for vectors containing values such as 0.01
    >> 
    >> For example, why is this happening:
    >> options(digits = 1)
    >>> 0.01
    >> [1] 0.01
    >> 
    >> 
    >> More examples:
    >>> options(digits = 7)
    >>> 0.1
    >> [1] 0.1
    >>> 0.01
    >> [1] 0.01
    >>> 0.11
    >> [1] 0.11
    >>> c(0.1,0.01)
    >> [1] 0.10 0.01
    >>> options(digits = 1)
    >>> 0.1
    >> [1] 0.1
    >>> 0.01
    >> [1] 0.01
    >>> 0.11
    >> [1] 0.1
    >>> c(0.1,0.01)
    >> [1] 0.10 0.01
    >>> 
    >> 
    >> The help file in ?options says:
    >> digits:
    >> controls the number of digits to print when printing numeric values. It is
    >> a suggestion only.
    >> 
    >> 
    >> Is this what is mean by "It is a suggestion only." ?