使用ggplot2迭代繪制列并動態重置ylab

給定資料幀 df1 和 df2 如下：

df1：

df1 <- structure(list(date = structure(c(1L, 2L, 4L, 5L, 6L, 7L, 8L, 
9L, 10L, 11L, 3L), .Label = c("2021/1/31", "2021/2/1", "2021/2/10", 
"2021/2/2", "2021/2/3", "2021/2/4", "2021/2/5", "2021/2/6", "2021/2/7", 
"2021/2/8", "2021/2/9"), class = "factor"), value1 = c(9.76, 
9.76, 9.88, 9.31, 9.71, 9.56, 9.27, 9.22, 9.21, 9.08, 8.78), 
    value2 = c(6.84, 6.88, 6.95, 6.65, 6.94, 6.85, 6.66, 6.66, 
    6.6, 6.5, 6.25), value3 = c(6.33, 6.21, 6.31, 6.2, 6.56, 
    6.36, 6.36, 6.25, 6.1, 6.02, 5.76), value4 = c(10.68, 10.91, 
    11, 10.49, 10.8, 10.5, 10.2, 9.85, 10.03, 9.8, 9.51), value5 = c(7.77, 
    7.84, 7.83, 7.44, 7.83, 7.77, 7.6, 7.46, 7.46, 7.39, 7.29
    )), class = "data.frame", row.names = c(NA, -11L))

df2：

df2 <- structure(list(type = structure(c(2L, 2L, 3L, 3L, 1L), .Label = c("pct_change", 
"price", "quantity"), class = "factor"), columns = structure(1:5, .Label = c("value1", 
"value2", "value3", "value4", "value5"), class = "factor"), unit = structure(c(3L, 
3L, 1L, 1L, 2L), .Label = c("", "%", "$"), class = "factor")), class = "data.frame", row.names = c(NA, 
-5L))

使用下面的代碼，我可以回圈所有基于列的列df2，這意味著對于每一列，如果其型別相同，則將它們繪制在同一個圖上，最后用型別名稱保存它們。

library(ggplot2)
library(data.table)
df1$date <- as.Date(df1$date)
df1.m <- melt(df1, id = "date")  # convert to long format
# add "type" variable to df1.m
df1.m2 = merge(df1.m, df2, by.x = "variable", by.y = "columns")

# for each "type", filter the data to that type, plot, and save    
for(my_type in unique(df1.m2$type)) {
  g <- ggplot(data = df1.m2[df1.m2$type == my_type,],
       aes(x=date, y = value, colour=variable))  
  geom_line(size = 1, alpha = 1) 
  print(g)
  # ggsave(paste0(my_type,".png"))
}

現在我希望ylab()為每個圖重置，這意味著如果它的型別相同，則ylab()使用unitfrom設定它df2。

我嘗試下面的代碼，但它不起作用：

for(my_type in unique(df1.m2$type)) 
  for (my_unit in unique(df1.m2$unit)){
  g <- ggplot(data = df1.m2[df1.m2$type == my_type,],
       aes(x=date, y = value, colour=variable))  
    ylab(my_unit)  
  geom_line(size = 1, alpha = 1) 
  print(g)
  # ggsave(paste0(my_type,".png"))
}

我怎樣才能根據上面的代碼實作這一目標？在此表示衷心的感謝。

uj5u.com熱心網友回復：

不確定您對嵌套的for. 據我所知，您可以通過使用unique(unit)過濾資料集的 的作為y比例標簽來實作您想要的結果：

library(ggplot2)
 
for(my_type in unique(df1.m2$type)) {
  d <- df1.m2[df1.m2$type == my_type,]
  g <- ggplot(data = d,
              aes(x=date, y = value, colour=variable))  
    geom_line(size = 1, alpha = 1)  
    labs(y = unique(d$unit))
  print(g)
}

uj5u.com熱心網友回復：

這是一種替代方法，可以完全避免遍歷資料幀。

1. 轉換df1為長格式并重命名name為columns

2. 加入到df2上columns

3. 改變列type以包括單位

4. 繪制值與日期、顏色依據columns和分面依據type

5. 進行一些主題調整以在每個面軸上顯示型別和單位

   library(ggplot2)
   library(dplyr)
   library(tidyr)
   
   df1 %>% 
     pivot_longer(2:6, 
                  names_to = "columns") %>% 
     left_join(df2) %>% 
     mutate(type = paste(type, unit)) %>% 
     ggplot(aes(date, value))   
     geom_line(aes(color = columns, 
                   group = columns))   
     facet_grid(type ~ ., 
                switch = 'y', 
                scales = "free_y")  
     theme(axis.title.y = element_blank(),
     strip.background = element_rect(fill = 'transparent'),
     strip.placement = 'outside',
     strip.text.y = element_text(angle=180))
   

結果：

uj5u.com熱心網友回復：

for(my_type in unique(df1.m2$type)) {
  
  g <- ggplot(
      data = df1.m2[type == my_type],
      aes(x=date, y = value, colour=variable)
    )  
    scale_y_continuous(labels = function(x) {
      if(my_type == "price") { 
        paste("$", x)
      } else if(my_type == "pct_change") {
        paste(x, "%")
      } else {
        x
      }
    })  
    geom_line(size = 1, alpha = 1) 
    print(g)
  # ggsave(paste0(my_type,".png"))
}

或者使用 if else 代替開關

scale_y_continuous(labels = function(x) {
  switch(my_type, "price" = paste("$", x), "pct_change" = paste(x, "%"), x)  
})

標籤：r for循环 ggplot2

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