如何创建 ggplots 列表？

Question

我有这三个数据框和这个功能

set.seed(1)
df1 <-
  data.frame(
    x = c("cat", "dog"),
    y = sample(1:100, 20),
    z = seq(ymd("2020-01-01"), ymd("2020-01-20"), by = "1 day")
  )

df2 <-
  data.frame(
    x = c("red", "green"),
    y = sample(1:100, 20),
    z = seq(ymd("2020-01-01"), ymd("2020-01-20"), by = "1 day")
  )

df3 <-
  data.frame(
    x = c("up", "down"),
    y = sample(1:100, 20),
    z = seq(ymd("2020-01-01"), ymd("2020-01-20"), by = "1 day")
  )


dataframes <-
  c("df1", "df2", "df3")

exploreDataFrames <- function(dataframes, sequence = seq_along(dataframes)){
  
  for (i in seq_along(sequence)){
    print(get(dataframes[i]))
    
    gg <-
      get(dataframes[i]) %>% 
      ggplot(aes(z, y, group = 1)) +
      geom_line() +
      facet_wrap(~get(names(get(dataframes[i]))[1]))
    
    return(gg)
  }
}

exploreDataFrames(dataframes[3])

我希望我的函数返回一个包含三个条目的列表：

list[1][1] <- name_of_the_dataframe
list[1][2] <- copy_of_the_complete_dataframe
list[1][3] <- ggplot_object

我的目标是能够拥有一个列表并遍历 ggplot 图表，快速能够按特定数据框的名称对其进行切片并提取完整的数据框。

我需要对我的功能进行哪些更改才能使其成为可能？

Answer 1

您可以使用

l = sapply(dataframes, function (dfname) {
      ggplot(get(dfname) , aes(z, y, group = 1)) +
      geom_line() +
      facet_wrap(~get(names(get(dfname))[1]))
    }, simplify = FALSE, USE.NAMES = TRUE)

然后 data.frame 名称在 names(l)

names(l[1])
# [1] "df1" 

数据在

l[[1]]$data

#     x  y          z
#1  cat 68 2020-01-01
#2  dog 39 2020-01-02
#3  cat  1 2020-01-03
#4  dog 34 2020-01-04
#5  cat 87 2020-01-05
#6  dog 43 2020-01-06
#7  cat 14 2020-01-07
#8  dog 82 2020-01-08
#9  cat 59 2020-01-09
#10 dog 51 2020-01-10
#11 cat 85 2020-01-11
#12 dog 21 2020-01-12
#13 cat 54 2020-01-13
#14 dog 74 2020-01-14
#15 cat  7 2020-01-15
#16 dog 73 2020-01-16
#17 cat 79 2020-01-17
#18 dog 37 2020-01-18
#19 cat 83 2020-01-19
#20 dog 97 2020-01-20