How do I align a histogram and boxplot so that they share x-axis?

Question

Data

 wages
# A tibble: 1,472 x 3
    wage educ  exper
   <dbl> <fct> <dbl>
 1  7.78 1        23
 2  4.82 1        15
 3 10.6  1        31
 4  7.04 1        32
 5  7.89 1         9
 6  8.20 1        15
 7  8.21 1        26
 8 10.4  1        23
 9 11.0  1        13
10  7.21 1        22
# ... with 1,462 more rows  

Aligning a histogram and boxplot

I am trying to align the histogram and boxplot of wage column using the cowplot package. I want them to share the x-axis, but the values are off a bit. See the reprex below:

library(tidyverse)
library(cowplot)

wages <- read_csv("http://vincentarelbundock.github.io/Rdatasets/csv/Ecdat/Bwages.csv") %>% 
  select(-X1, -sex) %>% 
  mutate(educ = factor(educ)) 
#> Warning: Missing column names filled in: 'X1' [1]
#> 
#> -- Column specification --------------------------------------------------------
#> cols(
#>   X1 = col_double(),
#>   wage = col_double(),
#>   educ = col_double(),
#>   exper = col_double(),
#>   sex = col_logical()
#> )


p1 <- ggplot(wages) +
  geom_histogram(aes(x = wage)) +
  geom_vline(xintercept = median(wages$wage), color = "red")

p2 <- ggplot(wages) + 
  geom_boxplot(aes(x = wage)) 

plot_grid(p1, p2, ncol = 1, axis = "l", align = 'v')
#> `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

^{Created on 2021-02-27 by the reprex package (v1.0.0)}

How can I make them perfectly share the x-axis?

Answer 1

You should not only set the limits, but also set the expanded range (to none) and the breaks:

p1 <- p1 +
  scale_x_continuous(limits= c(0,50), expand = c(0, 0), breaks = c(0,10,20,30,40,50))
p2 <- p2+
  scale_x_continuous(limits= c(0,50), expand = c(0, 0), breaks = c(0,10,20,30,40,50))

plot_grid(p1, p2, ncol = 1, axis = "l", align = 'v')

Answer 2

Just add xlim(0,50) to each ggplot call.