表达式+变量值+正式文本在绘图主题 [英] expression + variable value + normal text in plot maintitle

问题描述

我想在R情节中获得标题如下：

  title =您输入的意义级别是alpha = 0.05，经常使用。 
  

为了得到这个我将整个文本分成几部分，所以我终于可以写

  title = paste（part1，part2，part3，part4）
  

部分是：

  part1 =您输入的意义级别
 
 part2 =表达式（alpha）
 
 part3 = object @属性
 
 part4 =经常使用。 
  

所以我无法组合这些部分来获得我的结果。符号被正确显示，第3部分被打印为对象@属性（蚂蚁不是他的值），或者不显示符号，并且对象的值是打印正确。

我已经使用了？表达式和？print 但没有得到它

？plotmath 中提供的示例与我的案例也不匹配。

解决方案

一个解决方案是使用 bquote（）。在 bquote 中使用。（）来获取对象或表达式的值。以下是一个例子：

  obj = list（foo = 0，bar = 99，alpha = 0.05） 
 plot（1:10，main = bquote（Significance level is〜alpha ==。（obj $ alpha）））
  

波纹符号〜似乎需要说服 bquote 将alpha视为

i want to achieve an title in R plot as the following:

title = "The significance level you entered is alpha = 0.05 which is often used."

In order to get this I split the whole text in little parts, so i finally can write

title = paste(part1,part2,part3,part4)

The parts are:

part1 = "The significance level you entered is"

part2 = expression(alpha)

part3 = object@attribute

part4 = " which is often used."

So I'm not able to combine these parts to get my result.

Either the symbol is shown correctly and the part 3 is printed as object@attribute (ant not his value) or the symbol is not shown and the value of the object is printed correctly.

I used ?expressionand ?printalready, but didn't get it

The examples provided in ?plotmath didn't match my case either.

解决方案

One solution is to use bquote(). Use .() within bquote to get the value of objects or expressions. Here is one example of how that might work:

obj = list(foo=0, bar=99, alpha=0.05)
plot(1:10, main=bquote("Significance level is" ~ alpha == .(obj$alpha)))

The tilde ~ seems necessary here to convince bquote to treat alpha as a plotmath expression.

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