[R] Plot of a subset of a data.frame()

[ONKELINX, Thierry]

You could have a look at the ggplot2 package to make such plots. The code for the plots is more readable than with base plots.

a = c(1:10) 		# create a vector of integers
b = rep(c("a","b"),5)	# create a vector of chars, used
# as factor-levels	
d = rnorm(10)		# some random numbers
e = data.frame(a,b,d)

library(ggplot2)
ggplot(e, aes(x = a, y = d, colour = b, shape = b)) + geom_point()

a = c("a","b","c","d","e","f","g","h","i","j")
e = data.frame(a,b,d)       # re-build data.frame
ggplot(e, aes(x = a, y = d, colour = b, shape = b)) + geom_point()

HTH,

Thierry

----------------------------------------------------------------------------
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek
team Biometrie & Kwaliteitszorg
Gaverstraat 4
9500 Geraardsbergen
Belgium

Research Institute for Nature and Forest
team Biometrics & Quality Assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium

tel. + 32 54/436 185
Thierry.Onkelinx op inbo.be
www.inbo.be

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~ Sir Ronald Aylmer Fisher

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~ Roger Brinner

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> -----Oorspronkelijk bericht-----
> Van: r-help-bounces op r-project.org 
> [mailto:r-help-bounces op r-project.org] Namens Steffen Uhlig
> Verzonden: maandag 26 juli 2010 13:39
> Aan: r-help op r-project.org
> Onderwerp: [R] Plot of a subset of a data.frame()
> 
> Hello,
> 
> my data.frame is sort of a collection of process values, i.e. 
> huge run-chart. It consists of a time-stamp in the first 
> column (date as string), factors in the following columns 
> (used for subset-filtering), and some process-data columns.
> Hereafter, two examples are listed, showing the problems that 
> occour during print:
> 
> At first the example, that works fine:
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> a = c(1:10) 		# create a vector of integers
> b = rep(c("a","b"),5)	# create a vector of chars, used
> 			# as factor-levels	
> d = rnorm(10)		# some random numbers
> e = data.frame(a,b,d)	# connect to a data.frame
> 
> e.1 = subset(e, b=="a")	# create two subsets
> e.2 = subset(e, b=="b")
> plot(d~a, e.1, pch=3, col=2) # plot first data-subset 
> points(d~a, e.2, pch=4, col=3) # plot the 2nd one
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> all looks fine in theses plots.
> 
> 
> However, changing the content of vector "a" to a set of 
> strings the following happens:
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> a = c("a","b","c","d","e","f","g","h","i","j")
> e = data.frame(a,b,d)       # re-build data.frame
> 
> e.1 = subset(e, b=="a")     # create two subsets
> e.2 = subset(e, b=="b")
> plot(d~a, e.1, pch=3, col=2)
> points(d~a, e.2, pch=4, col=3)
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> The plot-command produces horizontal lines instead of dots. 
> This seems to happen when the x-axis contains strings rather 
> than numbers. is there a way out?
> 
> Best regards,
> /Steffen
> --
> Steffen Uhlig, PhD
> Mechatronik und Sensortechnik
> HTW des Saarlandes
> Goebenstraße 40
> 66117 Saarbrücken
> 
> Tel.: +49 (0) 681 58 67 274
> 
> ______________________________________________
> R-help op 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.
> 

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