使用ggplot2绘制时间序列的错误消息

时间:2013-02-11 14:34:51

标签: r ggplot2

我对ggplot2很新,并想知道是否有人可以帮我解决我的简单问题。我的示例数据帧如下所示。我想用时间(小时和分钟)来计算计数。

Date <- c("07/12/2012 05:00:00", "07/12/2012 06:00:00", "07/12/2012 07:00:00",
      "07/12/2012 08:00:00")
Date <- strptime(Date, "%d/%m/%Y %H:%M")
Counts <- c("0","3","10","6")
Counts <- as.numeric(Counts)
df1 <- data.frame(Date,Counts,stringsAsFactors = FALSE)

#Adds time to dataframe.
df1 <- within(df1,{
  posb <- as.POSIXlt(Date,format="%d/%m/%Y %H:%M")
hours <- posb$hour
mins <- posb$min
dates <- format(posb, "%x")
time <- format(posb, "%H:%M")
posb <- NULL  # cleanup
})
#Draw graph (time versus Counts)
library(ggplot2)
g = ggplot(df1, aes(x=time, y=Counts))
g + geom_line()

我总是收到错误消息'geom_path:每个组只包含一个观察。你需要调整群体审美吗?'

任何人都可以帮我纠正我的代码,让我的图表正确绘制吗?

修改 我仍然试图让我的时间变量的格式化工作,并绘制图形。但是目前,它还没有认识到日期格式。 我希望能够: 1.绘制一组设定的数据(例如从07:47:50到07:49:10)。 2.要求R每隔一分钟绘制x轴。 ......这些我现在都不能上班。我的实际数据的一个子集如下所示。感谢任何建议。

day3 <- structure(list(Date = c("11/12/2012", "11/12/2012", "11/12/2012", 
                            "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", 
                            "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", 
                            "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", "11/12/2012", 
                            "11/12/2012", "11/12/2012"), Time = c("07:46:10", "07:46:20", 
                                                                  "07:46:30", "07:46:40", "07:46:50", "07:47:00", "07:47:10", "07:47:20", 
                                                                  "07:47:30", "07:47:40", "07:47:50", "07:48:00", "07:48:10", "07:48:20", 
                                                                  "07:48:30", "07:48:40", "07:48:50", "07:49:00", "07:49:10", "07:49:20"
                            ), Axis1 = c(59L, 651L, 59L, 0L, 22L, 50L, 0L, 0L, 114L, 899L, 
                                         129L, 33L, 21L, 9L, 224L, 135L, 266L, 16L, 59L, 126L), Steps = c(1L, 
                                                                                                          2L, 1L, 0L, 2L, 1L, 0L, 0L, 5L, 15L, 6L, 2L, 2L, 0L, 8L, 5L, 
                                                                                                          16L, 1L, 3L, 8L)), .Names = c("Date", "Time", "Axis1", "Steps"
                                                                                                          ), row.names = 52838:52857, class = "data.frame")
#Creates a new dataframe with a time column.
day3 <- within(day3,{
  posb <- as.POSIXlt(Time,format="%H:%M:%S")
  posb <- NULL  # cleanup
})

library(ggplot2)
g = ggplot(day3, aes(x=strptime(Time, "%H:%M:%S"), y=Axis1)) + geom_line(aes(group = 1)) +
  theme_bw() +
  xlab("Time") + 
  ylab("Activity (Counts per 10 seconds)") + 
  scale_x_datetime(limits=c(as.POSIXct("07:47:50"),as.POSIXct("07:49:10")))


g

1 个答案:

答案 0 :(得分:1)

问题是由于您的time变量是一个字符向量:

R> class(df1$time)
[1] "character"

您必须将其传递给类POSIXlt的对象,例如:

ggplot(df1, aes(x=strptime(time, "%H:%M"), y=Counts)) + geom_line()

或者,更简单的是,您可以直接使用Date变量,而无需转换:

ggplot(df1, aes(x=Date, y=Counts)) + geom_line()

enter image description here

更好的是,您会看到ggplot2根据您沿轴的时间跨度自动标记您的x轴。

编辑:如果要定义x轴限制,可以执行以下操作:

ggplot(df1, aes(x=Date, y=Counts)) + geom_line() + scale_x_datetime(limits=c(as.POSIXct("2012/12/07 04:00:00"),as.POSIXct("2012/12/07 10:00:00")))