R: `plot.ts()` ylab 中的希腊字母

Question

plot.ts() 提供了一种可视化多元时间序列的便捷方式。不幸的是，我不知道如何用希腊字母注释（重复的）水平轴。熟悉的插入希腊字母的方法似乎不起作用，我尝试过的一些不太聪明的方法也不起作用：

testdata = matrix(rnorm(300), ncol = 3)
# doesn't work
plot.ts(testdata, ylab = expression(paste(pi[0], " = 0")))
# doesn't work
plot.ts(testdata, ylab = c(expression(paste(pi[0], " = 0")),
                           expression(paste(pi[0], " = 1")),
                           expression(paste(pi[0], " = 2"))))
# doesn't work
colnames(testdata) = c(expression(paste(pi[0], " = 0")),
                       expression(paste(pi[0], " = 1")),
                       expression(paste(pi[0], " = 2")))
plot.ts(testdata)
# doesn't work
plot.ts(testdata, ylab = parse(text = y))

我运行没主意了...

Answer 1

有一个解决方案使用library(zoo)

testdata = matrix(rnorm(300), ncol = 3)
plot(zoo::as.zoo(testdata),ylab=c(expression(mu),expression(sigma),expression(beta)),main="Win!")

改编自http://r.789695.n4.nabble.com/How-to-change-the-label-in-plot-ts-td796114.html

R: `plot.ts()` ylab 中的希腊字母

R: Greek letters in ylab of `plot.ts()`

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