r - 在 R 中的情节图例中有小节？

Question

我生成以下图例：

legend(
  "bottomleft"
  , legend=c(
    expression(bold("Long:" ~ (w==10^2 ~ ";" ~ h==10^5)))
    , expression(q[c] == 0.00 ~ ";" ~ beta == 0)
    , expression(q[c] == 0.05 ~ ";" ~ beta == 2)
    , expression(q[c] == 0.10 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.20 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.40 ~ ";" ~ beta == 10)
    , expression(bold("Wide:" ~ (w==10^3 ~ ";" ~ h==10^3)))
    , expression(q[c] == 0.00 ~ ";" ~ beta == 0)
    , expression(q[c] == 0.05 ~ ";" ~ beta == 2)
    , expression(q[c] == 0.10 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.20 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.40 ~ ";" ~ beta == 10)
  )
  , col=c("n", 1, 2, 3, 4, 5, -1, 1, 2, 3, 4, 5)
  , lty=c(F, 1, 1, 1, 1, 1, -1, 2, 2, 2, 2, 2)
  , cex=.65
)

这给了我：

有一个标题会更好，它也跨越“线+点”样本区域：

我怎么能意识到这一点？（例如，我尝试设置n或FALSE在 lty 部分中，但这不起作用，...）。我也未能对齐qc和 -beta值，但那是另一回事，......

Answer 1

使用@DWin提出的解决方法：

设置示例图：

plot(1:10,type="n")

保存图例并phantom隐藏要手动编写的标题

saveleg <- legend(
  "bottomleft"
  , legend=c(
      expression(phantom(bold("Long:" ~ (w==10^2 ~ ";" ~ h==10^5))))
    , expression(q[c] == 0.00 ~ ";" ~ beta == 0)
    , expression(q[c] == 0.05 ~ ";" ~ beta == 2)
    , expression(q[c] == 0.10 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.20 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.40 ~ ";" ~ beta == 10)
    , expression(phantom(bold("Wide:" ~ (w==10^3 ~ ";" ~ h==10^3))))
    , expression(q[c] == 0.00 ~ ";" ~ beta == 0)
    , expression(q[c] == 0.05 ~ ";" ~ beta == 2)
    , expression(q[c] == 0.10 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.20 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.40 ~ ";" ~ beta == 10)
  )
  , col=c("n", 1, 2, 3, 4, 5, -1, 1, 2, 3, 4, 5)
  , lty=c(F, 1, 1, 1, 1, 1, -1, 2, 2, 2, 2, 2)
  , cex=.65
  , trace=TRUE
)

text然后使用新指定的 x 轴值从保存的图例中获取要重新绘制的两位的 y轴值。

text(
    c(0.6,0.6),
    saveleg$text$y[c(1,7)],
    c(
      expression(bold("Long:" ~ (w==10^2 ~ ";" ~ h==10^5))),
      expression(bold("Wide:" ~ (w==10^3 ~ ";" ~ h==10^3)))
     ),
    cex=0.65,
    pos=4
)

结果：

Answer 2

类似的方法，但使用legend标题，并在之后添加矩形（框）之前创建两个图例（没有框）

plot(1)
# legend 1
l1 <- legend(
  "topleft"
  , legend=c(expression(q[c] == 0.00 ~ ";" ~ beta == 0)
    , expression(q[c] == 0.05 ~ ";" ~ beta == 2)
    , expression(q[c] == 0.10 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.20 ~ ";" ~ beta == 10)
    , expression(q[c] == 0.40 ~ ";" ~ beta == 10)),
  title = expression(bold("Long:" ~ (w==10^2 ~ ";" ~ h==10^5))),
  , col=c( 1, 2, 3, 4, 5)
  , lty=c(1, 1, 1, 1, 1)
  , cex=.65,
   bty='n')
# legend 2, placed directly below legend 1
l2 <- legend(x = l1$rect$left, y = with(l1$rect, top - h),
             legend =c(expression(q[c] == 0.00 ~ ";" ~ beta == 0)
                       , expression(q[c] == 0.05 ~ ";" ~ beta == 2)
                       , expression(q[c] == 0.10 ~ ";" ~ beta == 10)
                       , expression(q[c] == 0.20 ~ ";" ~ beta == 10)
                       , expression(q[c] == 0.40 ~ ";" ~ beta == 10)),
             title = expression(bold("Wide:" ~ (w==10^3 ~ ";" ~ h==10^3))),
              col=c( 1, 2, 3, 4, 5)
             , lty=c(  2, 2, 2, 2, 2)
             , cex=.65,
             bty='n')
# add the rectangle around the legend
rect(xleft = l1$rect$left, ybottom = with(l2$rect, top - h), 
     xright = l1$rect$left + max(l1$rect$w, l1$rect$w), ytop = l1$rect$top)