Re: [R] Why does plot() ignore the data type for axis labels?

From: Duncan Murdoch <>
Date: Tue, 19 Feb 2008 18:15:37 -0500

On 19/02/2008 5:40 PM, Stiffler wrote:
> Mark Difford wrote:

>>>> I was wondering why the plot() command ignores the datatype when
>>>> displaying axis labels...
>> plot() doesn't ignore the datatype:
>> [...]
>> plot(x,y) calls xy.coords(), which recasts x as: x = as.double(x), which
>> is fine, since x is (also/primarily) numeric.
>> HTH, Mark.

> Thanks for the explanation Mark.
> If integers are being recast as doubles R is ignoring/overriding the user's
> choice of data-type. There may be good reasons for doing that internally
> (uniformity, code re-use etc) , but it is not what I'd expect as an end-user
> --- neither ?plot nor ?xy.coords seem to mention that coordinates need to be
> floating point numbers.

They don't need to be floating point numbers, they are converted if not.

The point is that a scatterplot is a graph of real numbers, not of integers. Use a plot designed for a discrete data type if you don't want things displayed as their real values (see for example barplot, stripchart, dotchart, etc.)

Duncan Murdoch mailing list PLEASE do read the posting guide and provide commented, minimal, self-contained, reproducible code. Received on Tue 19 Feb 2008 - 23:26:43 GMT

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