R-从文本文件读取时间数据

Question

嗨，谢谢你，

因此，我目前正在尝试从文本文件中读取测试日期列表，该文件要尝试在带有一些测试值（称为数量）的图形上进行绘制。

我遇到的问题是，当从文件中读取时间时，它们无法正确读取。 当我将它们绘制到图形上时，这些值会非常失真且不正确，并且不会显示任何类似于日期的内容。

这是我的代码：

Frame <- read.table("....path.../Frame.txt")
Frame$Time <- as.Date(Frame$Time)
TheForecast <- naive(Frame)
plot(TheForecast, xlab="Time",ylab="Quantity",main="Stock Quantity vs Time",type='l')

我已经尝试过可以想到的文本文件中所有不同格式的日期，但是它们都返回相同的问题或更严重的问题。 这是我尝试过的：

Time <- c("01/01/2010", "07/02/2010", "08/03/2010", "02/04/2011", "11/05/2011", "12/06/2011", "06/07/2012", "08/30/2012", "04/16/2013", "03/18/2013", "02/22/2014", "01/27/2014", "12/15/2015", "09/28/2015", "05/04/2016", "11/07/2017", "09/22/2017", "04/04/2017")
Time <- c("2010-01-01", "2010-07-02", "2010-08-03", "2011-02-04", "2011-11-05", "2011-12-06", "2012-06-07", "2012-08-30", "2013-04-16", "2013-03-18", "2014-02-22", "2014-01-27", "2015-12-15", "2015-09-28", "2016-05-04", "2017-11-07", "2017-09-22", "2017-04-04")
Time <- c("1 January 2010", "7 February 2010", "8 March 2010", "2 April 2011", "11 May 2011", "12 June 2011", "6 July 2012", "30 August 2012", "16 April 2013", "18 March 2013", "22 February 2014", "27 January 2014", "15 December 2015", "28 September 2015", "4 May 2016", "7 November 2017", "22 September 2017", "4 April 2017")

以下是y（数量）轴的测试值，仅供参考：

Quantity <- c(5,3,8,4,0,5,2,7,4,2,6,8,4,7,8,9,4,6)

这是读取之前的文件示例：

Time Quantity
1 2010-01-01 5
2 2010-07-02 3
3 2010-08-03 8
4 2011-02-04 4
5 2011-11-05 0
6 2011-12-06 5
7 2012-06-07 2
8 2012-08-30 7
9 2013-04-16 4
10 2013-03-18 2
11 2014-02-22 6
12 2014-01-27 8
13 2015-12-15 4
14 2015-09-28 7
15 2016-05-04 8
16 2017-11-07 9
17 2017-09-22 4
18 2017-04-04 6

谢谢。

Answer 1

naive功能需要ts类或时间序列的对象才能正确显示图形。

file_path <- paste0(getwd(),"/data/Frame.txt")
Frame <- read.table(file_path, stringsAsFactors = FALSE)
Frame$Time <- as.Date(Frame$Time, format = "%Y-%m-%d")

这是您缺少的步骤：

Frame <- ts(Frame$Quantity, start = 1, end = NROW(Frame), frequency = 1)

然后进行其余操作，您的时间范围应该更加准确：

library(forecast)
TheForecast <- naive(Frame)
plot(TheForecast, xlab="Time",ylab="Quantity",main="Stock Quantity vs Time",type='l')

Answer 2

以下对我来说看起来不错：

## Your Data
df = read.table(text="Time Quantity
1 2010-01-01 5
2 2010-07-02 3
3 2010-08-03 8
4 2011-02-04 4
5 2011-11-05 0
6 2011-12-06 5
7 2012-06-07 2
8 2012-08-30 7
9 2013-04-16 4
10 2013-03-18 2
11 2014-02-22 6
12 2014-01-27 8
13 2015-12-15 4
14 2015-09-28 7
15 2016-05-04 8
16 2017-11-07 9
17 2017-09-22 4
18 2017-04-04 6",
header=TRUE, stringsAsFactors=FALSE)

## Convert string to date
df$Time = as.Date(df$Time, format="%Y-%m-%d")

plot(df, pch=20)