如何在 R 中绘制组直方图并添加趋势线？

Question

example graph

As picture shows above, I have data like

year  0-19years_old   20-44years_old  45-64years_old  above_65years old
2000   20000             34000            29000           16700
2005   19800             33000            28500           17000

I would like to draw the each age group separately histogram graph in r, and the x present year, y present count. It will be great if use different color for each histogram and give note in the side to say which color present what age group. Also draw another linear graph shows how each age group change for two years, here should be 4 lines in different color but in one graph.

Thanks for all help!

Answer 1

Something like this:

library(ggplot2)
library(tidyr)

dat <- tibble::tribble(
  ~year,  ~`0-19`,   ~`20-44`,  ~`45-64`, ~`65+`,
  2000,   20000,             34000,            29000,           16700,
  2005,   19800,             33000,            28500,           17000
) |> 
  pivot_longer(
    cols = -year,
    names_to = "age_group",
    values_to = "count"
  )
dat
#> # A tibble: 8 x 3
#>    year age_group count
#>   <dbl> <chr>     <dbl>
#> 1  2000 0-19      20000
#> 2  2000 20-44     34000
#> 3  2000 45-64     29000
#> 4  2000 65+       16700
#> 5  2005 0-19      19800
#> 6  2005 20-44     33000
#> 7  2005 45-64     28500
#> 8  2005 65+       17000

# Grouped bar chart
ggplot(dat) +
  aes(x = year, y = count, fill = age_group) +
  geom_col(position = "dodge")

# Line chart
ggplot(dat) +
  aes(x = year, y = count, color = age_group) +
  geom_line()

^{Created on 2021-05-30 by the reprex package (v2.0.0)}

The key ideas are:

1. Organize your data with the variables in columns.
2. Map age group to fill and/or color in the plot
3. Set position = "dodge" in geom_col() for the grouped bar chart

Answer 2

What you need is a bar chart not a histogram.

1. Bring your data into long format with pivot_longer
2. use geom_bar() for the bar chart
3. geom_line() for line chart
4. library(cowplot) to plot both plots side by side

library(tidyverse)
library(cowplot)

df1 <- df %>% 
  pivot_longer(
    cols = ends_with("old"),
    names_to = "names",
    values_to = "values"
  ) 

a <- ggplot(df1, aes(x=factor(year), y=values, fill=names)) +
  geom_bar(stat="identity", position = "dodge") + 
  geom_text(aes(label=values), vjust=1.6, color="black",
            position = position_dodge(0.9), size=3.5)+
  scale_fill_brewer(palette = "Set1")

b <- ggplot(df1, aes(x=factor(year), y=values, color=names, group=names)) +
  geom_point() + 
  geom_line() +
  scale_color_brewer(palette = "Set1")

plot_grid(a, b, labels = "AUTO")

data:

df <- tribble(
~year,  ~`0-19years_old`,   ~`20-44years_old`,  ~`45-64years_old`,  ~`above_65years_old`, 
2000,   20000,             34000,            29000,           16700,
2005,   19800,            33000,           28500,           17000)