purrr::walk 的嵌套循环留下空图

Question

以下代码生成绘图网格：

library(tidyverse)
library(grid)
library(patchwork)


exdata <- diamonds %>%
  group_by(cut) %>% 
  nest %>% 
  crossing(dummy = 1:3) %>% 
  crossing(cohort = LETTERS[1:3]) %>% 
  mutate(plots = map(.x = data, ~ ggplot(.x, aes(x = x, y = y)) + geom_point()))


# vars for plot grid
mod <- 'Fair'
colsn <- length(unique(exdata$dummy))
rowsn <- length(exdata$cohort %>% unique)

# create plots
wrap_plots(plotlist = exdata %>% filter(cut == mod) %>% pull(plots), ncol = colsn, nrow = rowsn) + plot_annotation(title = " ")

# add some text across columns
walk2(seq(0.165,0.835, length.out = colsn), unique(exdata$dummy), ~ grid.draw(textGrob(.y, x = .x, y = 0.98, rot = 0)))

看起来像这样：

在那个代码块中我有一个变量mod <- 'Fair'。我想让它成为一个矢量并为每种类型的钻石切割生成一个网格。尝试过：

mods <- exdata$cut %>% unique %>% as.vector

walk(mods, function(.x) {
  wrap_plots(plotlist = exdata %>% filter(cut == .x) %>% pull(plots), ncol = colsn, nrow = rowsn) + plot_annotation(title = " ")
  walk2(seq(0.165,0.835, length.out = colsn), unique(exdata$dummy), ~ grid.draw(textGrob(.y, x = .x, y = 0.98, rot = 0)))
})

这段代码似乎运行没有错误，但是没有重复全部返回。网格本身，只是没有情节：

我如何运行一个嵌套的遍历循环来为每种切割类型生成一个绘图网格？

Answer 1

只需将绘图包装在打印语句中即可解决问题

walk(mods, function(.x) {
  print(wrap_plots(plotlist = exdata %>% filter(cut == .x) %>% pull(plots), ncol = colsn, nrow = rowsn) + plot_annotation(title = " "))
  walk2(seq(0.165,0.835, length.out = colsn), unique(exdata$dummy), ~ grid.draw(textGrob(.y, x = .x, y = 0.98, rot = 0)))
})

purrr::walk 的嵌套循环留下空图

Nested loop with purrr::walk leaves empty plots

r

purrr