R：在带有 ggplot2 的条形图中使用日期

Question

我想创建一个条形图，在条形图的 y 轴上显示特定日期的日期条目数，在图表的 x 轴上显示日期。同时，我想将栏分成是和否部分。

Date,Hungry
Friday, March 24, 2017 2:33:46 PM,Yes
Friday, March 24, 2017 3:39:46 PM,No
Friday, March 24, 2017 4:39:46 PM,Yes
Friday, March 24, 2017 5:39:46 PM,No
Friday, March 24, 2017 6:39:46 PM,Yes
Friday, March 24, 2017 7:39:46 PM,Yes
Saturday, March 25, 2017 9:41:00 AM,Yes
Saturday, March 25, 2017 10:41:00 AM,Yes
Saturday, March 25, 2017 11:41:00 AM,No
Saturday, March 25, 2017 13:41:00 AM,No
Saturday, March 25, 2017 14:41:00 AM,No
Saturday, March 25, 2017 15:41:00 AM,Yes
Saturday, March 25, 2017 16:41:00 AM,Yes

总共有 6 个日期条目是 3 月 25 日（3 是/3 否）和 7 个日期条目是 3 月 26 日（4 是/3 否）。生成如下图：

Hungry
 ^
 |
 |
 |
 |
9|
 |              _
 |   _         |n|
 |  |n|        |o|
5|  |o|        |_|
 |  |_|        |y|
 |  |y|        |e|
 |  |e|        |s|
1|__|s|________|_|__________>
                            Date

     2          2            
     4          5            
     M          M            
     A          A
     R          R
     C          C
     H          H

很抱歉提出这个看似简单的问题。

编辑。 Adam Quek 让我通过dput 提供一些数据。这里有几行：

dat <- structure(list(Date = structure(1:4, .Label = c("Friday, March 24, 2017 4:39:46 PM", 
"Friday, March 24, 2017 7:21:33 PM", "Friday, March 24, 2017 7:21:51 PM", 
"Friday, March 24, 2017 7:22:00 PM", "Friday, March 24, 2017 7:22:14 PM", 
"Saturday, March 25, 2017 8:00:10 AM", "Saturday, March 25, 2017 8:00:25 AM", 
"Saturday, March 25, 2017 8:00:46 AM", "Saturday, March 25, 2017 8:01:02 AM", 
"Saturday, March 25, 2017 8:01:20 AM", "Saturday, March 25, 2017 8:01:37 AM", 
"Saturday, March 25, 2017 8:01:50 AM"), class = "factor"), Hungry = structure(c(2L, 
1L, 2L, 1L), .Label = c("No", "Yes"), class = "factor")), .Names = c("Date", 
"Hungry"), row.names = c(NA, 4L), class = "data.frame")

Answer 1

这是一种快速绘制所需内容的方法。

library(ggplot2)
ggplot(dat, aes(date, fill=as.factor(hungry))) + 
      geom_bar()

我将数据重新制作为：

dat <- structure(list(date = structure(c(17249, 17249, 17249, 17249, 
17249, 17249, 17250, 17250, 17250, 17250, 17250, 17250, 17250
), class = "Date"), hungry = structure(c(2L, 1L, 2L, 1L, 2L, 
2L, 2L, 2L, 1L, 1L, 1L, 2L, 2L), .Label = c("No", "Yes"), class = "factor")), class = "data.frame", .Names = c("date", 
"hungry"), row.names = c(NA, -13L))

编辑：

带有新示例数据的附加输入：

(i) 在 R 中将日期更改为可读的日期格式。在日期/时间格式上查看 strptime 的 R 帮助文件

dat$date <- as.Date(dat$Date, "%A, %B %d, %Y %X")

(ii) 与上述类似的 ggplot 绘图。

ggplot(dat, aes(date, fill=Hungry)) + 
      geom_bar()