One label on the y axis and the second one leave it at the top. Using facet_wrap with 2 variables

I want to add a y-axis on each facet. facet_wrap(scales="free_y") doesn't do what I want because switch=y moves both variables and I want to move only one.

Is it possible to do something about it?
Do you know if there is another way to get the axis on each facet the same way scales="free_y" does?.

Thank you for the time.

#code for figure 
 ggplot(df,aes(factor(Year),Value,colour=Model,group=Model))+
geom_line(size=0.6)+
  scale_colour_manual(values = c("Black","blue","darkgreen","red"))+
  #scale_colour_manual(values = c("Black","#00539CFF","#006B38FF","#E94B3CFF"))+
scale_x_discrete(labels=c(1981,2005,2026,2050,2075,2100),breaks=factor(c(1981,2005,2026,2050,2075,2100)),expand = c(0.04,0.04))+
  facet_grid(Variable~Location,scales = "free_y",switch = "y", # flip the facet labels along the y axis from the right side to the left
             labeller = as_labeller(c(CDD = "CDD (Days)",CWD="CWD (Days)",R20="R20 (Days)",R50= "R50 (Days)",R95P="R95P (mm)",R99P="R99p (mm)",
                                      RX5DAY="RX5DAY (mm)",SDII="SDII (mm/day)",Bimodal="Bimodal",Unimodal="Unimodal")))+
  labs(x="Year",y=element_blank(),colour=element_blank())+
  guides(colour = guide_legend(override.aes = list(size = 2)))+
  theme_bw(base_size = 15)+
  theme(strip.background = element_blank(), # remove the background
        strip.placement = "outside",legend.position = "bottom",
        legend.text = element_text(size = 15),
        axis.text = element_text(colour="black"))#,
        panel.spacing.x = unit(-0.90, "lines"),
        panel.spacing.y = unit(-0.80, "lines"))```

df<-structure(list(Year = c(2091, 2091, 2091, 2092, 2092, 2092, 2093, 
2093, 2093, 2094, 2094, 2094, 2095, 2095, 2095, 2096, 2096, 2096, 
2097, 2097, 2097, 2098, 2098, 2098, 2099, 2099, 2099, 2100, 2100, 
2100, 2091, 2091, 2091, 2092, 2092, 2092, 2093, 2093, 2093, 2094, 
2094, 2094, 2095, 2095, 2095, 2096, 2096, 2096, 2097, 2097, 2097, 
2098, 2098, 2098, 2099, 2099, 2099, 2100, 2100, 2100), Variable = c("CDD", 
"CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", 
"CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", 
"CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", 
"CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", 
"CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", 
"CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", "CDD", 
"CDD", "CDD", "CDD", "CDD", "CDD"), Location = c("Unimodal", 
"Unimodal", "Unimodal", "Unimodal", "Unimodal", "Unimodal", "Unimodal", 
"Unimodal", "Unimodal", "Unimodal", "Unimodal", "Unimodal", "Unimodal", 
"Unimodal", "Unimodal", "Unimodal", "Unimodal", "Unimodal", "Unimodal", 
"Unimodal", "Unimodal", "Unimodal", "Unimodal", "Unimodal", "Unimodal", 
"Unimodal", "Unimodal", "Unimodal", "Unimodal", "Unimodal", "Bimodal", 
"Bimodal", "Bimodal", "Bimodal", "Bimodal", "Bimodal", "Bimodal", 
"Bimodal", "Bimodal", "Bimodal", "Bimodal", "Bimodal", "Bimodal", 
"Bimodal", "Bimodal", "Bimodal", "Bimodal", "Bimodal", "Bimodal", 
"Bimodal", "Bimodal", "Bimodal", "Bimodal", "Bimodal", "Bimodal", 
"Bimodal", "Bimodal", "Bimodal", "Bimodal", "Bimodal"), Model = c("RCP2.6", 
"RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", 
"RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", 
"RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", 
"RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", 
"RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", 
"RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", 
"RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", 
"RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", "RCP2.6", "RCP4.5", "RCP8.5", 
"RCP2.6", "RCP4.5", "RCP8.5"), Value = c(188.47, 184.03, 199.62, 
172.65, 204.21, 186.82, 179.75, 196.57, 198.9, 185.33, 193.11, 
197.07, 174.92, 200.37, 210.65, 176.48, 200.01, 203.91, 170.33, 
200.67, 192.44, 164.03, 200.35, 188.92, 169, 208.69, 196.54, 
183.62, 203.8, 201.36, 135.92, 141.75, 145.53, 111.85, 145.43, 
160.49, 127.08, 144.34, 155.95, 127.36, 154.24, 155.37, 127.92, 
135.34, 155.45, 139.08, 146.16, 160.27, 129.21, 151.82, 145.07, 
108.86, 161.75, 146.93, 134.71, 155.76, 157.29, 117.42, 155.58, 
150.69)), row.names = c(NA, -60L), class = c("tbl_df", "tbl", 
"data.frame"))

Solution

Maybe this is what you are looking for. One way to get a y-axis on each facet is to make use of patchwork, i.e. make separate plots for each column of the grid and glue the plots together. One drawback: Both x-axis get labelled:

library(ggplot2)
library(dplyr)
library(patchwork)

make_plot <- function(d, switch = NULL) {
  ggplot(d, aes(factor(Year), Value, colour = Model, group = Model)) +
    geom_line(size = 0.6) +
    scale_colour_manual(values = c("Black", "blue", "darkgreen", "red")) +
    scale_x_discrete(labels = c(1981, 2005, 2026, 2050, 2075, 2100), breaks = factor(c(1981, 2005, 2026, 2050, 2075, 2100)), expand = c(0.04, 0.04)) +
    facet_grid(Variable ~ Location,
               scales = "free_y", 
               switch = switch, # flip the facet labels along the y axis from the right side to the left
               labeller = as_labeller(c(
                 CDD = "CDD (Days)", CWD = "CWD (Days)", R20 = "R20 (Days)", R50 = "R50 (Days)", R95P = "R95P (mm)", R99P = "R99p (mm)",
                 RX5DAY = "RX5DAY (mm)", SDII = "SDII (mm/day)", Bimodal = "Bimodal", Unimodal = "Unimodal"
               ))
    ) +
    guides(colour = guide_legend(override.aes = list(size = 2))) +
    labs(x = "Year", y = NULL, colour = NULL) +
    theme_bw(base_size = 15) +
    theme(
      strip.background = element_blank(), # remove the background
      strip.placement = "outside", legend.position = "bottom",
      legend.text = element_text(size = 15),
      axis.text = element_text(colour = "black")
    )  
}

p1 <- make_plot(filter(df, Location == "Bimodal"), switch = "y")
p2 <- make_plot(filter(df, Location == "Unimodal"), switch = "y")


p1 + p2 + plot_layout(guides = "collect") &
  theme(legend.position='bottom')