在 plotmath 表达式中包含文本控制字符

问题描述

有没有办法获取文本字符串的控制字符，例如"" 用于 newline 在 plotmath 表达式中求值，反之亦然.在下面的例子中，我想结合:

• 一些字符文本
• 文本控制字符(换行符)
• 替换变量名
• 包含绘图数学表达式

在阅读这个问题后，我可以用替代来解决大部分问题，但是换行符代码> 字符不被评估.我现在绕圈子，把自己弄糊涂了 plotmath、parse、bquote 和 substitute.在 plotmath 的 帮助页面 中，它说 >

与普通绘图不同，控制字符(例如)不会在 plotmath 中的字符串中解释.

这是否意味着它真的不可能?

lab = "一些数据"形式 = "指数"x = 1:10y = x^2绘图( x , y , type = "b" )标题(主要 = 替代(粘贴(Plot of"，phi，of:"，lab，
函数形式:"，form)，list(lab=lab，form=form))，adj=0)

解决方案

正如你所想象的 plotmath 不支持换行符，但你可以使用 mtext 和 >bquote，写每一行.例如，我创建了一个行列表:

Lines <- list(bquote(paste( "Plot of " , phi , " of: " , .(lab))),bquote(paste("函数形式:" , .(form)))mtext(do.call(expression, Lines),side=3,line=1:0)

Is there any way to get control characters for text strings, e.g. "" for newline evaluated inside a plotmath expression, or vice versa. In the following example, I would like to combine:

• some character text
• text control character (newline)
• substitute a variable name
• include a plotmath expression

After reading this question I can get most of the way there with substitute, but the newline character is not evaluated. I am now going round in circles and confusing myself with plotmath, parse, bquote and substitute. In the help page for plotmath it says

Does this mean it really is impossible?

lab = "some data"
form = "Exponential"
x = 1:10
y = x^2


plot( x , y , type = "b" )
title( main = substitute( paste( "Plot of " , phi , " of: "  , lab , "
Functional form: " , form ) , list(lab = lab , form = form ) ) , adj = 0 )

解决方案

As you have figured plotmath does not support newlines within, but you can use mtext with bquote, to write each line. For example I create a list of lines :

Lines <- list(bquote(paste( "Plot of " , phi , " of: "  , .(lab))),
              bquote(paste("Functional form: " , .(form)))

mtext(do.call(expression, Lines),side=3,line=1:0)

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