为什么直方图调用 2，值 1.5

Question

这是我的数据结构

str(databody)
'data.frame':   259 obs. of  2 variables:
 $ Genes_bodies: Factor w/ 259 levels "FBgn0000045",..: 142 5 82 118 107 241 165 66 78 67 ...
 $ Frenq       : int  4 4 4 4 4 4 5 4 3 2 ...
 - attr(*, "na.action")=Class 'omit'  Named int [1:1109] 260 261 262 263 264 265 266 267 268 269 ...
  .. ..- attr(*, "names")= chr [1:1109] "260" "261" "262" "263" ...

h = hist(databody$Frenq)
h$density = h$counts/sum(h$counts)*100
plot(h,freq=F, col= "red")

dput(h)
structure(list(breaks = c(1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 
5.5, 6), counts = c(28L, 47L, 0L, 65L, 0L, 69L, 0L, 42L, 0L, 
8L), density = c(10.8108108108108, 18.1467181467181, 0, 25.0965250965251, 
0, 26.6409266409266, 0, 16.2162162162162, 0, 3.08880308880309
), mids = c(1.25, 1.75, 2.25, 2.75, 3.25, 3.75, 4.25, 4.75, 5.25, 
5.75), xname = "databody$Frenq", equidist = TRUE), .Names = c("breaks", 
"counts", "density", "mids", "xname", "equidist"), class = "histogram")

str(h)
List of 6
 $ breaks  : num [1:11] 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 ...
 $ counts  : int [1:10] 28 47 0 65 0 69 0 42 0 8
 $ density : num [1:10] 10.8 18.1 0 25.1 0 ...
 $ mids    : num [1:10] 1.25 1.75 2.25 2.75 3.25 3.75 4.25 4.75 5.25 5.75
 $ xname   : chr "databody$Frenq"
 $ equidist: logi TRUE
 - attr(*, "class")= chr "histogram"

h$counts 47 不应该低于 1.5 但低于 2？我做错了什么和错过了什么？还有一种方法可以制作具有 h$ 密度的单个堆叠条形图吗？

Answer 1

hist 会将数据分成连续的间隔，而不是特定的整数值。如果您的数据都是整数值，那么以下选项之一可能更适合您：

# Fake data
set.seed(1095)
x = sample(1:10, 100, replace=TRUE)

# Base graphics
plot(table(x), lwd=3)

# ggplot2
library(ggplot2)

ggplot(as.data.frame(x), aes(factor(x))) +
  geom_bar(width=0.5, fill="grey30")

我不确定堆叠条形图在这里是否有效，但以下是如何在 ggplot 中创建一个：

ggplot(as.data.frame(table(x)), aes(x="my_label", y=Freq, fill=Freq)) +
  geom_bar(stat='identity', position="stack") +
  geom_text(aes(label=paste0(x, ": Freq = ", Freq), y=cumsum(Freq) - 0.5*Freq),
            colour="white") +
  labs(x="")

为什么直方图调用 2，值 1.5

Why is histogram calling 2, value 1.5

r

histogram

bar-chart