ggplot2----Guides:axes and legen

详细说明二级坐标轴

This function is used in conjunction with a position scale to create a secondary axis, positioned opposite of the primary axis. All secondary axes must be based on a one-to-one transformation of the primary axes.
这个函数需要与一个位置刻度一起使用，以创建一个与主轴相反的中轴。所有次级轴都必须建立在主坐标轴的一对一变换上。

用法

sec_axis(trans = NULL, name = waiver(), breaks = waiver(), labels = waiver())

dup_axis(trans = ~., name = derive(), breaks = derive(), labels = derive())

derive()

参数

trans

A transformation formula
一个转化的公式

name

The name of the secondary axis
二级坐标轴的名称

breaks One of:
NULL　　for no breaks
waiver()　for the default breaks computed by the transformation object
A numeric vector of positions
A function that takes the limits as input and returns breaks as output

labels One of:
NULL　　for no labels
waiver()　for the default labels computed by the transformation object
A character vector giving labels (must be same length asbreaks)
A function that takes the breaks as input and returns labels as output

Details

sec_axis is used to create the specifications for a secondary axis. Except for thetrans argument any of the arguments can be set to derive() which would result in the secondary axis inheriting the settings from the primary axis. dup_axis is provide as a shorthand for creating a secondary axis that is a duplication of the primary axis, effectively mirroring the primary axis.
sec_axis用于为二级轴创建规范。除了反式参数外，任何参数都可以被设置为derive()，这将导致二级坐标轴从主轴继承设置。dup_axis提供了一个简写，用于创建一个副轴，这是主轴的复制，有效地称为主轴的镜像。

Examples

p <- ggplot(mtcars, aes(cyl, mpg)) + geom_point()
# Create a simple secondary axisp + scale_y_continuous(sec.axis = sec_axis(~.+10))

# Inherit the name from the primary axis
p + scale_y_continuous("Miles/gallon", sec.axis = sec_axis(~.+10, name = derive()))

# Duplicate the primary axis
p + scale_y_continuous(sec.axis = dup_axis())

# You can pass in a formula as a shorthand
p + scale_y_continuous(sec.axis = ~.^2)