使用因子作爲您的x軸縮放時，更改x軸限制

Question

是否可以在兩側將x軸限制增加1。例如，在下面的圖中可以將xlimits更改爲3和9？即xlim(3,9)

p <- ggplot(mtcars, aes(factor(cyl), mpg)) 
p + geom_boxplot() 

當試圖xlim()我得到：

Error: Discrete value supplied to continuous scale 

，當我嘗試scale_x_continuous(limits = c(3,9))我得到：

Error in if (zero_range(from) || zero_range(to)) return(rep(mean(to), : 
    missing value where TRUE/FALSE needed 
In addition: Warning messages: 
1: In loop_apply(n, do.ply) : 
    no non-missing arguments to min; returning Inf 
2: In loop_apply(n, do.ply) : 
    no non-missing arguments to max; returning -Inf 
3: In loop_apply(n, do.ply) : 
    position_dodge requires constant width: output may be incorrect 

Answer 1

你想scale_x_discrete：

p <- ggplot(mtcars, aes(factor(cyl), mpg)) 
p + geom_boxplot() + scale_x_discrete(limits = c("4","6")) 

或xlim：

p <- ggplot(mtcars, aes(factor(cyl), mpg)) 
p + geom_boxplot() + xlim("4", "6") 

編輯：要求包括更寬的範圍。要包括其他值，則需要使用中斷功能，各種因素的列表：

p <- ggplot(mtcars, aes(factor(cyl), mpg)) 
p + geom_boxplot() + 
    scale_x_discrete(breaks = factor(3:9), limits = c("3", "4", "5", "6", "7", "8", "9")) 

在這種情況下，你必須繪製出了8缸箱線圖，如果你不給假8：

p + geom_boxplot() + 
    scale_x_discrete(breaks=factor(c("3","4","5","6","7", "eight", "9")), 
        limits = c("3", "4", "5", "6", "7", "eight", "9") 

或繪圖前篩選出來：

mtcars<-mtcars[mtcars$cyl!=8,] 

參考：scale_x_discrete