R：在直方图上将 X 轴更改为“整数”

Question

我正在使用 R 编程语言。我下载了以下世界人口数据并尝试制作直方图：

#data source: https://population.un.org/wpp/Download/Files/1_Indicators%20(Standard)/CSV_FILES/WPP2019_TotalPopulationBySex.csv

`WPP2019_TotalPopulationBySex.(1)` <- read.csv("C:/Users/ME/Downloads/WPP2019_TotalPopulationBySex (1).csv")

world_data = WPP2019_TotalPopulationBySex.(1)

> head(world_data)
  LocID    Location VarID Variant Time MidPeriod  PopMale PopFemale PopTotal PopDensity
1     4 Afghanistan     2  Medium 1950    1950.5 4099.243  3652.874 7752.117     11.874
2     4 Afghanistan     2  Medium 1951    1951.5 4134.756  3705.395 7840.151     12.009
3     4 Afghanistan     2  Medium 1952    1952.5 4174.450  3761.546 7935.996     12.156
4     4 Afghanistan     2  Medium 1953    1953.5 4218.336  3821.348 8039.684     12.315
5     4 Afghanistan     2  Medium 1954    1954.5 4266.484  3884.832 8151.316     12.486
6     4 Afghanistan     2  Medium 1955    1955.5 4318.945  3952.047 8270.992     12.669


world_data$PopMale = as.numeric(substr(world_data$PopMale,1,1))
world_data$PopFemale = as.numeric(substr(world_data$PopFemale,1,1))
world_data$PopTotal = as.numeric(substr(world_data$PopTotal,1,1))
world_data$PopDensity = as.numeric(substr(world_data$PopDensity,1,1))

我尝试制作直方图：

library(ggplot2)
library(scales)
library(cowplot2)

g1 = ggplot(world_data, aes(x=PopMale)) + geom_histogram() +   + ggtitle("Male Population") 
g2 = ggplot(world_data, aes(x=PopFemale)) + geom_histogram() +  ggtitle("Female Population")
g3 = ggplot(world_data, aes(x=PopTotal)) + geom_histogram() + ggtitle("Total Population")
g4 = ggplot(world_data, aes(x=PopDensity)) + geom_histogram()+  ggtitle("Population Density")


plot_row = plot_grid(g1, g2, g3, g4)

# now add the title
title <- ggdraw() + 
  draw_label(
    "World Population: Does Benford's Law Exist?",
    fontface = 'bold',
    x = 0,
    hjust = 0
  ) +
  theme(
    # add margin on the left of the drawing canvas,
    # so title is aligned with left edge of first plot
    plot.margin = margin(0, 0, 0, 7)
  )
plot_grid(
  title, plot_row,
  ncol = 1,
  # rel_heights values control vertical title margins
  rel_heights = c(0.1, 1)
)

问题：我正在尝试格式化直方图的 x 轴，以便它们显示整数（例如 0,1,2,3,4,5,6,7,8,9 ）。我尝试使用以下代码来执行此操作：

integer_breaks <- function(n = 5, ...) {
fxn <- function(x) {
breaks <- floor(pretty(x, n, ...))
names(breaks) <- attr(breaks, "labels")
breaks
}
return(fxn)
}


library(ggplot2)

g1 = ggplot(world_data, aes(x=PopMale)) + geom_histogram() +    scale_y_continuous(breaks = integer_breaks()) + ggtitle("Male Population") 
g2 = ggplot(world_data, aes(x=PopFemale)) + geom_histogram() +  scale_y_continuous(breaks = integer_breaks()  +  ggtitle("Female Population")
g3 = ggplot(world_data, aes(x=PopTotal)) + geom_histogram() +   scale_y_continuous(breaks = integer_breaks() + ggtitle("Total Population")
g4 = ggplot(world_data, aes(x=PopDensity)) + geom_histogram()+  scale_y_continuous(breaks = integer_breaks() + ggtitle("Population Density")


plot_row = plot_grid(g1, g2, g3, g4)

# now add the title
title <- ggdraw() + 
  draw_label(
    "World Population: Does Benford's Law Exist?",
    fontface = 'bold',
    x = 0,
    hjust = 0
  ) +
  theme(
    # add margin on the left of the drawing canvas,
    # so title is aligned with left edge of first plot
    plot.margin = margin(0, 0, 0, 7)
  )
plot_grid(
  title, plot_row,
  ncol = 1,
  # rel_heights values control vertical title margins
  rel_heights = c(0.1, 1)
)

问题：但这仍然像以前一样显示 x 轴。

谁能告诉我如何解决这个问题？

谢谢！

参考资料：

• How to display only integer values on an axis using ggplot2

Answer 1

我找到了答案：

library(ggplot2)

g1 = ggplot(world_data, aes(x=PopMale)) + geom_histogram() +    scale_x_continuous(breaks = seq(0, 10,1)) + ggtitle("Male Population") 
g2 = ggplot(world_data, aes(x=PopFemale)) + geom_histogram() +  scale_x_continuous(breaks = seq(0, 10,1)) +  ggtitle("Female Population")
g3 = ggplot(world_data, aes(x=PopTotal)) + geom_histogram() +  scale_x_continuous(breaks = seq(0, 10,1)) + ggtitle("Total Population")
g4 = ggplot(world_data, aes(x=PopDensity)) + geom_histogram()+  scale_x_continuous(breaks = seq(0, 10,1)) + ggtitle("Population Density")


plot_row = plot_grid(g1, g2, g3, g4)

# now add the title
title <- ggdraw() + 
  draw_label(
    "World Population: Does Benford's Law Exist?",
    fontface = 'bold',
    x = 0,
    hjust = 0
  ) +
  theme(
    # add margin on the left of the drawing canvas,
    # so title is aligned with left edge of first plot
    plot.margin = margin(0, 0, 0, 7)
  )
plot_grid(
  title, plot_row,
  ncol = 1,
  # rel_heights values control vertical title margins
  rel_heights = c(0.1, 1)
)

Answer 2

对于这种情况，你应该制作条形图而不是直方图：

library(tidyverse)
df <- read_csv("https://population.un.org/wpp/Download/Files/1_Indicators%20(Standard)/CSV_FILES/WPP2019_TotalPopulationBySex.csv")
#> 
#> ── Column specification ────────────────────────────────────────────────────────
#> cols(
#>   LocID = col_double(),
#>   Location = col_character(),
#>   VarID = col_double(),
#>   Variant = col_character(),
#>   Time = col_double(),
#>   MidPeriod = col_double(),
#>   PopMale = col_double(),
#>   PopFemale = col_double(),
#>   PopTotal = col_double(),
#>   PopDensity = col_double()
#> )
dfplot <- df %>%
    select(starts_with("Pop")) %>%
    pivot_longer(cols = everything(), names_to = "variable", values_to = "value") %>%
    mutate(firstdigit = substr(as.character(value), 1, 1))

ggplot(dfplot, aes(firstdigit)) +
    geom_bar() +
    facet_wrap(~variable)

^{由reprex package (v2.0.1) 于 2021 年 10 月 28 日创建}