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

Martin Maechler maechler at stat.math.ethz.ch
Tue Mar 21 11:10:51 CET 2017

```>>>>> 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." ?

```