更改x軸標籤，以特定的字母r

Question

林做了很多R中地塊和我的代碼的一部分是這樣的：

plot(x=0,y=0, type="n", ylim=c(0,250), xlim=c(0,8), bty="n", main = "Line 20 male 3 sec rep 2", 
    xlab = "Concentration", ylab = "MM above buttom") 
fc <- levels(dat20m2$Conc) 
for(i in 1:length(fc)){ 
    tmp <- dat20m2[dat20m2$Conc==fc[i],] 
    points(y=tmp$t30.sum,x=rep(i,length(tmp$t30))) 
    points(y=mean(tmp$t30.sum),x=i,col="red") 
} 
abline(lm(t30.sum~as.integer(Conc),data=dat20m2), lty=2) 

我的X軸是0：8，但我會就喜歡be是A，B，C，D，E，X，Y，我可以使它與字母表一起工作，但當我想跳一些字母時，我會陷入困境。有人可以幫助我嗎？

Answer 1

plot(x=0,y=0, type="n", ylim=c(0,250), xlim=c(0,8), bty="n", main = "Line 20 male 3 sec rep 2", 
    xlab = "Concentration", ylab = "MM above buttom", xaxt="n") 

## added xaxt="n" 
## and the axis code below 
axis(1,at=0:7,labels=c("0","A","B","C","D","E","X","Y")) 
fc <- levels(dat20m2$Conc) 
for(i in 1:length(fc)){ 
    tmp <- dat20m2[dat20m2$Conc==fc[i],] 
    points(y=tmp$t30.sum,x=rep(i,length(tmp$t30))) 
    points(y=mean(tmp$t30.sum),x=i,col="red") 
} 
abline(lm(t30.sum~as.integer(Conc),data=dat20m2), lty=2) 

我從here得到了答案，我已經通過添加雙磅符號描述的兩個部分修改你的代碼。希望這可以幫助。