使用来自向量和下标的希腊符号绘制轴标签

Question

如何将下面的代码更改为：

• 符号后的下标（例如，在 LaTeX 中为 $\alpha_R$、$\beta_R$、$\gamma_R$）
• “日志”和符号之间的空格（尝试按照建议放置“~”，但没有成功）

这是Plotting axis labels with Greek symbols from a vector 和Subscripts in plots in R 的混合问题。

# vector of symbols to go in graphs
symbol_list <- c("alpha", "beta", "gamma");
set.seed(1234);

count <- 1;
for (symbol in symbol_list){

    # random data
    x <- runif(10, 0,1); 
    y <- runif(10, 0,1);

    png(paste0("test",count,".png"));
    # make graph with different symbol in x label at each iteration 
    plot(x,y, xlab=parse(text = paste("log *",symbol)));
    dev.off();

    count <- count+1;
}

Answer 1

应该这样做。如果循环遍历索引i，则不需要计数器。

symbol_list = c("alpha", "beta", "gamma")
for (i in 1:length(symbol_list)){
  # random data
  x <- runif(10, 0,1); 
  y <- runif(10, 0,1);
  png(paste0("test",i,".png"));
  # make graph with different symbol in x label at each iteration 
  plot(x,y, xlab=parse(text=paste("log~",symbol_list[i],"[R]")))
dev.off();
}