How can I break to a new row in a facet_wrap based on factor levels using two factors?

Question

How can I make each new row begin with a new factor level? Currently it wraps based on batch and sample but does not break at a new factor level of batch. When trying 'facet_grid(~batch~sample)' there are many unwanted empty panels.

The results from R and the desired result from Photoshop.

EDITED to include smaller reproducible dataset

df <- data.frame("sample" = c("A1","A2","A3","A4","A5","A6","A7","A8","A9","A10","A11"), 
                 "length_um" = c(1.8,1.9,0.52,0.75,0.14,0.95,0.84,0.46,0.25,0.13,0.31),
                 "breadth_um" = c(1.44,1.52,0.41,0.60,0.12,0.76,0.68,0.37,0.20,0.11,0.25),
                 "batch" = c("batch01","batch01","batch01","batch01","batch02","batch02","batch02","batch02","batch02","batch03","batch03"))

df <- df %>%
  mutate_if(sapply(df, is.character), as.factor)

ggplot(df, aes(x=length_um,y=breadth_um)) +
  geom_point()+
  facet_wrap(~batch~sample)

LuizZ · Answer 1 · 2020-11-11T02:58:02.610

0

Try to replace facet_wrap(~batch~sample) for facet_grid(~batch~sample) .

edited Nov 11 '20 at 02:58

answered Nov 11 '20 at 01:16

LuizZ

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Hard to say more without having a [reproducible example](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example). But facet_grid() will likely solve your problem. – LuizZ Nov 11 '20 at 03:01
I am glad that you improved your question, because now it is more likely that someone can help you. Unfortunately, Idk how to do what you want. – LuizZ Nov 12 '20 at 14:56

Archymedes · Answer 2 · 2021-03-12T14:00:44.790

It is not possible to do it yet? The only solution I can imagine is to split dataframe by "batch" variable, and arrange the resulting multi-plot. Rewritten code from this post. I would like an integrated facet_wrap argument to do it cleaner

library(ggplot2)
library(cowplot)
library(dplyr)

# Sample dataframe
df = data.frame(
  sample = c('A1','A2','A3','A4','A5','A6','A7','A8','A9','A10','A11'), 
  length_um = c(1.8,1.9,0.52,0.75,0.14,0.95,0.84,0.46,0.25,0.13,0.31),
  breadth_um = c(1.44,1.52,0.41,0.60,0.12,0.76,0.68,0.37,0.20,0.11,0.25),
  batch = c('batch01','batch01','batch01','batch01','batch02','batch02','batch02','batch02','batch02','batch03','batch03')
)

# Set factors to facet
facet = c('batch', 'sample')

# Maximum number of levels
n_facet_max = split(df, df[[facet[1]]]) %>%
  lapply(function(x) n_distinct(x[[facet[2]]])) %>%
  unlist() %>% 
  max()

# Plot function
my_fun = function(x) {
  
  plot_tmp = ggplot(x, aes(x = length_um, y = breadth_um)) +
    geom_point()+
    facet_grid(
      x[[facet[1]]] ~ x[[facet[2]]]
    )
  
  n_facet = n_distinct(x[[facet[2]]])
  
  if (n_facet < n_facet_max) {
    plot_tmp = plot_grid(
      NULL,
      plot_tmp,
      axis = 'tb',
      ncol = 2,
      rel_widths = c(n_facet_max - n_facet, n_facet)
    )
  }
  
  return(plot_tmp)
  
}

# Plot per 'batch' variable
plot_ls = split(df, df[[facet[1]]]) %>% lapply(function(x) my_fun(x))

# Layout
plot_grid(
  plotlist = plot_ls,
  ncol = 1,
  axis = 'r'
)

How can I break to a new row in a facet_wrap based on factor levels using two factors?

2 Answers2