how to automatically align the axis limits for different ggplots-CodePudding

I am running regression and presenting the results using ggplots. Generally, the intention is to see the dynamic effect of a policy that happened in period 2.

I am plotting the regression results, the dataframe I created from the regression functions looks like

dfplot1 <- data.frame(coef=c(0.05,0,0.1,0.15,0.2), 
                      se=c(0.1,0,0.1,0.1,0.1), 
                      period=1:5)
dfplot2 <- data.frame(coef=c(0.05,0,0.12,0.18,0.24), 
                      se=c(0.12,0,0.12,0.12,0.12), 
                      period=1:5)

And I plot the coefficients with standard errors using

library(ggplot2)
library(patchwork)

p1 <- ggplot(dfplot1) 
  geom_point(aes(x=period, y=coef)) 
  geom_segment(aes(x=period, xend=period, y=coef-1.96*se, yend=coef 1.96*se)) 
  geom_segment(aes(x=period, xend=period, y=coef-1.96*se, yend=coef 1.96*se))  
  labs(x='Year', y='Coefficients') 
  geom_hline(yintercept = 0, linetype = "dashed") 
  theme(panel.background = element_blank())
p2 <- ggplot(dfplot2) 
  geom_point(aes(x=period, y=coef)) 
  geom_segment(aes(x=period, xend=period, y=coef-1.96*se, yend=coef 1.96*se)) 
  geom_segment(aes(x=period, xend=period, y=coef-1.96*se, yend=coef 1.96*se))  
  labs(x='Year', y='Coefficients') 
  geom_hline(yintercept = 0, linetype = "dashed") 
  theme(panel.background = element_blank())
p1|p2

The figure looks like,

I can use ylim in each ggplot to set the y axis limit and make them the same like

p1 ylim(-0.5,0.5)
p2 ylim(-0.5,0.5)

To better visualize and compare the coefficients in these two regressions with different covariates, is there a way to automatically find the best fit and align the axes of the two ggplots?

Thank you very much!

CodePudding user response：

You can harvest the ranges from both plots using layer_scales, then get the overall range of the concatenated result to use in ylim. This avoids the need for guessing.

lim <- range(c(layer_scales(p1)$y$range$range, layer_scales(p2)$y$range$range))

p1   ylim(lim) | p2   ylim(lim)

CodePudding user response：

You could facet_wrap:

library(tidyverse)

dfplot1 <- data.frame(coef=c(0.05,0,0.1,0.15,0.2), 
                      se=c(0.1,0,0.1,0.1,0.1), 
                      period=1:5)
dfplot2 <- data.frame(coef=c(0.05,0,0.12,0.18,0.24), 
                      se=c(0.12,0,0.12,0.12,0.12), 
                      period=1:5) 

df <- bind_rows(dfplot1, dfplot2, .id = "id")

df |> ggplot(aes(period, coef))  
  geom_point()  
  geom_segment(aes(xend = period, y = coef - 1.96 * se, yend = coef   1.96 * se))  
  labs(x = "Year", y = "Coefficients")  
  geom_hline(yintercept = 0, linetype = "dashed")  
  facet_wrap(~id)  
  theme(panel.background = element_blank())

^{Created on 2022-05-27 by the}