[R情節 - Y軸，繪製的值是不相關的

Question

我有點新的R和我想要繪製如下：

x <- c(1:13) 
y <- c(19.77, 18.07, 20.55, 16.42, 18.47, 20.18, 22.91, 13.18, 18.07, 17.05, 13.45, 11.11, 22.52) 
y2 <- c(26.93, 24.5, 25.73, 23.65, 20.50, 29.58, 18.8, 17.38, 12.2, 18.17, 12.55, 15.63, 26.07) 
par(mar=c(5,7,5,3), pch=22, col="Black") 
plot(x, y2, main="TITLE", xaxt = "n", xlab='', yaxt = "n", ylab = "", type="b", col="Blue") 
par(new = TRUE) 
plot(x, y, xaxt = "n", xlab='', yaxt = "n", ylab = "", type="b", col="cyan", pch=21) 
range <- seq(0, 30, 1) 
axis(1, at=x, labels=x) 
axis(2, at=range, labels=range, las=1) 
mtext(side = 1, text = "X", line = 3, col="Black") 
mtext(side = 2, text = "Tiempo", line = 5, xpd=FALSE, col="Black") 
# Legend. 
legend(x= "bottomleft", y=0.92, legend=c("Exp1","Exp2"), col=c("cyan", "blue"), pch=c("_","_")) 

它繪製確定，具體如下：

但是，我覺得y軸與真實值不相關。例如，在數據（y和y2）中，我們可以看到其中一個最大值是26.93，但在數據中，根據該圖的最高值大約爲23。

我一直在玩範圍變量，但我還沒有找到任何方法來糾正這一點。谷歌一直沒有幫助，因爲我不知道我該如何搜索這個問題。你們有沒有任何想法我做錯了什麼？

此外，我希望值範圍從0到30，而不是從11到23.也許這與問題有關。

任何提示將是有價值的！提前致謝。

Answer 1

住在儘可能靠近你的代碼，你可以改變線＃5，＃7是這樣的：

plot(y2 ~ x, main="TITLE", xaxt = "n", xlab='', yaxt = "n", ylab = "", type = "b", col = "Blue", ylim = c(0,30)) 
lines(y ~ x, xaxt = "n", xlab = '', yaxt = "n", ylab = "", type = "b", col = "cyan", pch = 21) 

Answer 2

使用matplot：

matplot(x, cbind(y2,y), t='b', col = c("blue", "cyan"), pch = c(22, 21), lty = c(1,1),　xaxt = "n", xlab="", yaxt = "n", ylab = "") 
axis(1, at=x, labels=x) 
axis(2, at=range, labels=range, las=1) 
mtext(side = 1, text = "X", line = 3, col="Black") 
mtext(side = 2, text = "Tiempo", line = 5, xpd=FALSE, col="Black") 
legend(x= "bottomleft", y=0.92, legend=c("Exp1","Exp2"), col=c("cyan", "blue"), pch=c("_","_"))