scale_continuous

scale_x_continuous(name=NULL, limits=NULL, breaks=NULL, labels=NULL, trans=NULL, expand=c(0.05, 0), minor_breaks=NULL, formatter="scientific", ...)
scale_y_continuous(name=NULL, limits=NULL, breaks=NULL, labels=NULL, trans=NULL, expand=c(0.05, 0), minor_breaks=NULL, formatter="scientific", ...)

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Parameters

Parameters control the appearance of the scale. In addition to the parameters listed below (if any), any aesthetic can be used as a parameter, in which case it will override any aesthetic mapping.

• name: name of scale to appear in legend or on axis. Maybe be an expression: see ?plotmath
• limits: numeric vector of length 2, giving the extent of the scale
• breaks: numeric vector indicating where breaks should lie
• labels: character vector giving labels associated with breaks
• trans: a transformer to use
• expand: numeric vector of length 2, giving multiplicative and additive expansion factors
• minor_breaks: NULL
• formatter: NULL
• ...: ignored

Returns

This function returns a scale object.

See also

• scale_discrete: Discrete position scales

Examples

> (m <- qplot(rating, votes, data=subset(movies, votes > 1000), na.rm = T)) 
  
>  
> # Manipulating the default position scales lets you: 
>  
> #  * change the axis labels 
> m + scale_y_continuous("number of votes") 
  
> m + scale_y_continuous(expression(votes^alpha)) 
  
>  
> #  * modify the axis limits 
> m + scale_y_continuous(limits=c(0, 5000)) 
  
> m + scale_y_continuous(limits=c(1000, 10000)) 
  
> m + scale_x_continuous(limits=c(7, 8)) 
  
>  
> # you can also use the short hand functions xlim and ylim 
> m + ylim(0, 5000) 
  
> m + ylim(1000, 10000) 
  
> m + xlim(7, 8) 
  
>  
> #  * choose where the ticks appear 
> m + scale_x_continuous(breaks=1:10) 
  
> m + scale_x_continuous(breaks=c(1,3,7,9)) 
  
>  
> #  * manually label the ticks 
> m + scale_x_continuous(breaks=c(2,5,8), labels=c("two", "five", "eight")) 
  
> m + scale_x_continuous(breaks=c(2,5,8), labels=c("horrible", "ok", "awesome")) 
  
> m + scale_x_continuous(breaks=c(2,5,8), labels=expression(Alpha, Beta, Omega)) 
  
>  
> # There are also a wide range of transformations you can use: 
> m + scale_y_log10() 
  
> m + scale_y_log() 
  
> m + scale_y_log2() 
  
> m + scale_y_sqrt() 
  
> m + scale_y_reverse() 
  
> # see ?transformer for a full list 
>  
> # You can control the formatting of the labels with the formatter 
> # argument.  Some common formats are built in: 
> x <- rnorm(10) * 100000 
> y <- seq(0, 1, length = 10) 
> p <- qplot(x, y) 
> p + scale_y_continuous(formatter = "percent") 
  
> p + scale_y_continuous(formatter = "dollar") 
  
> p + scale_x_continuous(formatter = "comma") 
  
>  
> # qplot allows you to do some of this with a little less typing: 
> #   * axis limits 
> qplot(rating, votes, data=movies, ylim=c(1e4, 5e4)) 
Warning: Removed 58018 rows containing missing values (geom_point).
  
> #   * axis labels 
> qplot(rating, votes, data=movies, xlab="My x axis", ylab="My y axis") 
  
> #   * log scaling 
> qplot(rating, votes, data=movies, log="xy") 
  

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© Hadley Wickham 2010