From: Mark Difford <mark_difford_at_yahoo.co.uk>

Date: Wed, 20 Feb 2008 00:26:35 -0800 (PST)

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

*>
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*> The point is that a scatterplot is a graph of real numbers, not of
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*> integers. Use a plot designed for a discrete data type if you don't
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*> want things displayed as their real values (see for example barplot,
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*> stripchart, dotchart, etc.)
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*>
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*> Duncan Murdoch
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*>
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Date: Wed, 20 Feb 2008 00:26:35 -0800 (PST)

Hi Stiffler,

Duncan Murdoch wrote:

>> 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 ...

To drive home Duncan's point (not that it needs it) ...and to complete the loop, consider how R treats factors:

*> x
*

[1] 1 2 3

> factor(x)

[1] 1 2 3

Levels: 1 2 3

## And:

> factor(x, labels=c("one", "two", "three"))

[1] one two three

Levels: one two three

> unclass(factor(x, labels=c("one", "two", "three")))

[1] 1 2 3

attr(,"levels")

[1] "one" "two" "three"

It does, in the end, make perfect sense.

HTH, Mark.

Duncan Murdoch-2 wrote:

*>
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> 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.

-- View this message in context: http://www.nabble.com/Why-does-plot%28%29-ignore-the-data-type-for-axis-labels--tp15562325p15584404.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help_at_r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.Received on Wed 20 Feb 2008 - 08:30:38 GMT

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