Is it possible to change the ylim and xlim when th

问题:

As an example, if I want to draw a plot with points 1-5 and add points 5-9, the following would work:

> plot(c(1,2,3,4,5), ylim=c(0,10))
> points(c(5,6,7,8,9))

However, if I don't know beforehand what numbers the to-be-added points will be (they could be 5-9, could also be 20-29), I can't set the ylim and xlim beforehand. I would like to be able to do something like the following (which does not work):

> plot(c(1,2,3,4,5))
> points(c(5,6,7,8,9), ylim=c(0,10)) 

Is something like this possible?

回答1:

(Just for completeness.)

This is almost certainly impossible in R base graphics. Other answers point out that it's doable in ggplot. It might be possible in something like the playwith package, although a short bit of playing around hasn't shown me a way to do it.

回答2:

You can alter the axes limits in ggplot2. For example,

require(ggplot2)
data(mpg) 

g = ggplot(mpg, aes(cyl, cty)) + geom_point() + xlim(5, 8)
g
g + xlim(4,8)

As Ben Bolker mentions, in base graphics, you definitely can't do it without additional packages.

回答3:

with ggplot2 you can modify the axis:

df <-data.frame(age=c(10,10,20,20,25,25,25),veg=c(0,1,0,1,1,0,1),extra=c(10,10,20,20,25,25,90))
 g=ggplot(data=df,aes(x=age,y=veg))
 g=g+stat_summary(fun.y=mean,geom="point")
 g

then

a<-g+coord_cartesian(xlim=c(0,100))
a+geom_point(data=df,aes(x=extra,y=veg))

回答4:

Would this be good enough? It treats the upper bound of ylim as a variable, but technically you would know ylim before adding the points:

my.data <- seq(0,5)
my.points <- seq(5,9)
plot(my.data, ylim=c(0,max(my.data,my.points)))
points(my.points)

You could also treat the lower bound of ylim the same way:

my.data <- seq(0,5)
my.points <- seq(5,9)
plot(my.data, ylim=c(min(my.data,my.points),max(my.data,my.points)))
points(my.points)