R中使用ggplot2进行正态分布的直方图

Question

我试图用ggplot2绘制直方图。

我在R

中为此编写了一个简单的代码

dnorm.count <- function(x, mean = 0, sd = 1, log = FALSE, n = 1, binwidth = 1){
  n * binwidth * dnorm(x = x, mean = mean, sd = sd, log = log) 
}
mtcars %>% 
  ggplot(aes(x =  mpg)) +
  geom_histogram(bins =60,color = "white", fill = "#9FE367",boundary = 0.5) +
  geom_vline(aes(xintercept = mean(mpg)), 
             linetype="dashed",
             size = 1.6, 
             color = "#FF0000")+
  geom_text(aes(label = ..count..), stat= "count",vjust = -0.6)+
  stat_function(fun = dnorm.count, color = "#6D67E3", 
                args = list(mean= mean(mtcars$mpg), 
                            sd = sd(mtcars$mpg),
                            n = nrow(mtcars)), 
                lwd = 1.2) +
  scale_y_continuous(labels = comma, name = "Frequency") +
  scale_x_continuous(breaks=seq(0,max(mtcars$mpg)))+
  geom_text(aes(label = paste0("mean = ", round(mean(mtcars$mpg), 2)), 
                x = mean(mtcars$mpg)*1.2, 
                y  = mean(mtcars$mpg)/5))+
  geom_vline(aes(xintercept = sd(mpg)), linetype="dashed",size = 1.6, color = "#FF0000") 

我得到的就是这个！

问题是如何绘制与此类似的直方图

使用ggplot2并且可以将代码转换为R函数吗？

编辑：为了更好地解释我尝试做的事情：

我想创建一个直方图，与使用ggplot2引用的直方图完全相同，然后我想创建一个相同的函数来减少编码。使用你喜欢的任何包+ ggplot2。直方图应该有描绘标准偏差的线条。意思是像参考中的那个。如果可能的话，将图中的标准偏差描述为参考图像，这是我试图实现的目标。

Answer 1

如果您的问题如何绘制直方图，就像您在上一张图中所附的直方图一样，这9行代码会产生非常相似的结果。

public class TestBarchart {

public static void main(String[] args) throws Exception {
    // TODO Auto-generated method stub
    Barchart bc = new Barchart();
    bc.startApplication("C:/temp","Test","100","60","40","");
    bc.startApplication("C:/temp","Test 2","100","60","40","");

    }

}

您可以使用library(magrittr) ; library(ggplot2) set.seed(42) data <- rnorm(1e5) p <- data %>% as.data.frame() %>% ggplot(., aes(x = data)) + geom_histogram(fill = "white", col = "black", bins = 30 ) + geom_density(aes( y = 0.3 *..count..)) + labs(x = "Statistics", y = "Probability/Density") + theme_bw() + theme(axis.text = element_blank()) 添加符号或文字，annotate()可以使用geom_segment来显示图表上的间隔：

p + annotate(x = sd(data)/2 , y = 8000, geom = "text", label = "σ", size = 10) +
    annotate(x = sd(data) , y = 6000, geom = "text", label = "2σ", size = 10) +
    annotate(x = sd(data)*1.5 , y = 4000, geom = "text", label = "3σ", size = 10) +     
    geom_segment(x = 0, xend = sd(data), y = 7500, yend = 7500) +
    geom_segment(x = 0, xend = sd(data)*2, y = 5500, yend = 5500) +
    geom_segment(x = 0, xend = sd(data)*3, y = 3500, yend = 3500) 

这段代码会给你这样的东西：