R语言基础学习系列八-用ggplot2 画片段分布直方图

这次使用ggplot2画片段分布图，一起学习的小伙伴加个好友，互相学习共同进步

数据是自己分析的到的片段数据

data <- read.table("fragment.length.txt", header = F)
# # 设置插入片段长度的阈值，过滤掉太长的片段
length_cutoff <- 1200
fragment <- data$V1[data$V1 <= length_cutoff]
head(fragment)
df <- data.frame(fragment)
head(df)
# 利用直方图统计频数分布，设置柱子个数
breaks_num <- 500
res <- hist(df, breaks = breaks_num, plot = FALSE)
# 添加坐标原点
plot(x = c(0, res$breaks),
     y = c(0, 0, res$counts) / 10^2,
     type = "l", col = "red",
     xlab = "Fragment length(bp)",
     ylab = expression(Normalized ~ read ~ density ~ 10^2),
     main = "Sample Fragment sizes")

fragment.png

下面的参考代码来自：

Histogram with density in ggplot2 | R CHARTS (r-charts.com)

# install.packages("ggplot2")
library(ggplot2)

# Histogram with Fragment length
ggplot(df, aes(x = fragment)) + 
  geom_histogram(aes(y = ..density..),
                 colour = 1, fill = "white") +
  geom_density(lwd = 1, colour = 4,
               fill = 4, alpha = 0.25) 

image.png

下面画的趋势会平滑好看一些