R：带有持续时间的ggplot

Question

问题：您对ggplot2 处理持续时间的建议（作者：Hadley Wickham）。具体来说：使用自定义中断和合适的标签重现下面的图。偏好最少使用自定义函数和/或重构数据。欢迎对我未引用的软件包提出建议。

数据以秒为单位存储（参见下面的df）。我想显示人眼可读的中断和标签，例如天而不是数千秒，其中中断发生在 0、1、2... 天，而不是尴尬的分数。

努力证明：下面的第一个示例将持续时间作为整数处理，并通过适当的逐个除以 60/24/365 的倍数等来实现目标。第二个示例使用基数 R@987654334 @对象。为了在这种情况下正确处理，我必须使用strptime 函数并减去1。我错过了什么吗？第三个示例使用来自lubridate 包的duration 类。虽然使用day() 和seconds_to_period() 函数指定标签非常容易，但我在设置自定义中断方面做得并不好。第四个示例使用hms 类。我设法指定了休息时间，但没有指定标签。也欢迎任何有关如何为以下每个示例编写更短代码行的建议。

# Data
df = data.frame(x = 1:6, 
    num = c(374400, 343500, 174000, 193500, 197700, 270300))

# base/difftime
df$difftime <- as.difftime(df$num, units = "secs")

# lubridate/duration
library("lubridate")  # devtools::install_github("tidyverse/lubridate") # the dev version fixes a bug
df$duration <- duration(df$num, units = "seconds")

# hms/hms
library("hms")
df$hms <- as.hms(df$num) 

library("ggplot2")
library("scales")

# 1: data is base/numeric
# Pro: no package dependence
# Con: Hard work 
breaks = seq(0, 100*60*60, 20*60*60)
labels = function(x) round(x/60/60/24, 0)
ggplot(data = df, aes(x = x, y = num)) +
    geom_bar(stat = "identity", fill = "lightblue") +
    scale_y_continuous(name = "Duration (Days)", 
                       breaks = breaks,
                       labels = labels) +
    labs(title = "Data stored as numeric (seconds)", 
         subtitle = "breaks = seq(0, 100*60*60, 20*60*60)\nlabels = function(x) round(x/60/60/24, 0)",
         x = NULL) 
ggsave("base-num.png")

# 2: data is base/difftime
# Pro: simple once you get over the ``strftime(x, "%d")`` syntax.
# Unresolved: Why do I need to subtract a day?
labels = function(x) as.integer(strftime(x, "%d"))-1
ggplot(data = df, aes(x = x, y = difftime)) +
    geom_bar(stat = "identity", fill = "lightblue") +
    scale_y_time(name = "Duration (Days)", 
        labels = labels) +
    labs(title = "Data stored as difftime (seconds)", 
         subtitle = "default breaks\nlabels = function(x) as.integer(strftime(x, '%d'))-1",
         x = NULL) 
ggsave("base-difftime.png")

# 3: data is lubridate/duration
# Pro: intuitive combination of day() and seconds_to_period() functions
# Unresolved: a better way to make own breaks?
breaks = as.duration(seq(0, 5, 1)*60*60*24)
labels = function(x) day(seconds_to_period(x))
ggplot(data = df, aes(x = x, y = duration)) +
    geom_bar(stat = "identity", fill = "lightblue") +
    scale_y_continuous(name = "Duration (Days)", 
        breaks = breaks,
        labels = labels) +
    labs(title = "Data stored as duration (seconds)", 
         subtitle = "breaks = as.duration(seq(0, 5, 1)*60*60*24)\nlabels = function(x)lubridate::day(lubridate::seconds_to_period(x))",
         x = NULL) 
ggsave("lubridate-duration.png")

# 4: data is hms/hms
# Pro: Immediately generates plot with acceptable labels
# Unresolved: how to make own labels:  Failed attempts:
labels = 0:(length(breaks)-1)
labels = function(x)lubridate::day(x)

breaks = seq(0, 5, 1)*60*60*24
ggplot(data = df, aes(x = x, y = hms)) +
    geom_bar(stat = "identity", fill = "lightblue") +
    scale_y_continuous(name = "Duration (Seconds)",
        breaks = breaks) +
    labs(title = "Data stored as hms (seconds)", 
         subtitle = "breaks = seq(0, 5, 1)*60*60*24\ndefault labels",
         x = NULL) 
ggsave("hms-hms.png")

编辑 按照 Axeman 在 cmets 部分的建议，这是如何将 ggplot 与 hms 对象结合起来。这在我看来是 4 种中最方便的一种，尽管不得不承认必须减去 1 是出乎意料的。 Axeman，你想发布这个作为答案吗？

breaks = hms::hms(days = 0:4)
labels = function(x) lubridate::day(x)-1

Answer 1

恕我直言，我提出的解决方案看起来过于复杂。

如果持续时间以整数秒的形式给出并且需要以天为单位绘制，我的方法是在对aes() 的调用中对其进行缩放：

df = data.frame(x = 1:6, 
                num = c(374400, 343500, 174000, 193500, 197700, 270300))
library("ggplot2")
ggplot(data = df, aes(x = x, y = num / (24*60*60))) +
  geom_col(fill = "lightblue") +
  labs(title = "Data stored as numeric (seconds)",
       y = "Duration (Days)",
       x = NULL) 

因此，无需纠结于中断和标签。

注意：geom_col() 是 geom_bar(stat = "identity") 的替代品。