How to add y axis title for each facet row in ggplot?-CodePudding

The

The numbers of facet rows is two in this example because df$group2 has two different values. For my actual use case there may be more than two rows depending on the used facet variable; the y axis title is supposed to be in the middle of each facet row.

Best solution so far is

CodePudding user response：

Without using another package, I felt that the best method would be to build upon the spaces solution you linked in the original question. So I wrote a function to make the label spacing a little bit more robust.

ylabel <- function(label1,label2){ L1 <- nchar(label1) L2 <- nchar(label2) scaler <- ifelse(L1 L2 > 8, 4, 0) space1 = paste0(rep("",27 - (L1/2)),collapse = " ") space2 = paste0(rep("",44 - (L1/2 L2/2) - scaler), collapse = " ") space3 = paste0(rep("",22 - (L2/2)), collapse = " ") paste0(space1,label1,space2,label2,space3) }

Application:

test <- ylabel("automobiles", "trucks") ggplot(df, aes(x, y)) geom_point() facet_grid(group1 ~ group2) ylab(test)

Still playing around with the scaler parameter, it's not perfect:

test2 <- ylabel("super long label", "a") ggplot(df, aes(x, y)) geom_point() facet_grid(group1 ~ group2) ylab(test2)

Will continue to refine the function/parameters, but am thinking this will get you close to what you're looking for.

CodePudding user response：

You can copy the axis labels into new grobs in the gtable

library(ggplot2) library(grid) library(gtable) library(cowplot) g = ggplot(df, aes(x, y)) geom_point() facet_grid(group1 ~ group2) gt = ggplot_gtable(ggplot_build(g)) which.ylab = grep('ylab-l', gt$layout$name) gt = gtable_add_grob(gt, gt$grobs[which.ylab], 8, 3) gt = gtable_add_grob(gt, gt$grobs[which.ylab], 10, 3) gt = gtable_remove_grobs(gt, 'ylab-l') grid.draw(gt)

CodePudding user response：

Maybe this could be helpful. Here we use switch and do some theme mainpulations.

# altered dataframe df <- df <- data.frame(x= rnorm(100), y= rnorm(100), group1= c(rep(0:1, 40), rep(2,20)), group2= rep(2:3, each= 50)) library(ggplot2) ggplot(df, aes(x, y)) geom_point() facet_grid(group1 ~ group2, switch = 'y') theme( axis.title.y = element_blank(), strip.background = element_rect(fill = 'transparent'), strip.placement = 'outside', strip.text.y = element_text(angle=180))