colClasses 日期和时间 read.csv

发布于 2024-10-21 06:02:14 字数 580 浏览 1 评论 0原文

我有一些以下形式的数据：

date,time,val1,val2
20090503,0:05:12,107.25,1
20090503,0:05:17,108.25,20
20090503,0:07:45,110.25,5
20090503,0:07:56,106.25,5

来自 csv 文件。我对 R 比较陌生，所以我尝试

data <-read.csv("sample.csv", header = TRUE, sep = ",")

在 colClasses 参数中使用 POSIXlt 以及 POSIXct ，但我似乎不能能够从我的日期和时间数据中创建一列或“变量”。我想这样做，这样我就可以选择任意时间范围来计算运行统计数据，例如最大值、最小值、平均值（然后是箱线图等）。

我还认为我可以将其转换为时间序列并以这种方式绕过它，

dataTS <-ts(data)

但尚未能够利用开始、结束和频率来发挥我的优势。感谢您的帮助。

原文

I have some data of the form:

date,time,val1,val2
20090503,0:05:12,107.25,1
20090503,0:05:17,108.25,20
20090503,0:07:45,110.25,5
20090503,0:07:56,106.25,5

that comes from a csv file. I am relatively new to R, so I tried

data <-read.csv("sample.csv", header = TRUE, sep = ",")

and using POSIXlt, as well as POSIXct in the colClasses argument, but I cant seem to be able to create one column or 'variable' out of my date and time data. I want to do so, so I can then choose arbitrary timeframes over which to calculate running statistics such as max, min, mean (and then boxplots, etc.).

I also thought that I might convert it to a time series and get around it that way,

dataTS <-ts(data)

but have yet been able to use the start, end, and frequency to my advantage. Thanks for your help.

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感性 2024-10-28 06:02:14

使用 colClasses 参数将数据读入 R 时无法执行此操作，因为数据跨越 CSV 文件中的两个“列”。相反，加载数据并将 date 和 time 列处理到单个 POSIXlt 变量中：

dat <- read.csv(textConnection("date,time,val1,val2
                               20090503,0:05:12,107.25,1
                               20090503,0:05:17,108.25,20
                               20090503,0:07:45,110.25,5
                               20090503,0:07:56,106.25,5"))
dat <- within(dat, Datetime <- as.POSIXlt(paste(date, time),
                                          format = "%Y%m%d %H:%M:%S"))

[我认为它是年月日？？，如果不使用 "%Y%d%m %H:%M:%S"]

则给出：

> head(dat)
      date    time   val1 val2            Datetime
1 20090503 0:05:12 107.25    1 2009-05-03 00:05:12
2 20090503 0:05:17 108.25   20 2009-05-03 00:05:17
3 20090503 0:07:45 110.25    5 2009-05-03 00:07:45
4 20090503 0:07:56 106.25    5 2009-05-03 00:07:56
> str(dat)
'data.frame':   4 obs. of  5 variables:
 $ date    : int  20090503 20090503 20090503 20090503
 $ time    : Factor w/ 4 levels "0:05:12","0:05:17",..: 1 2 3 4
 $ val1    : num  107 108 110 106
 $ val2    : int  1 20 5 5
 $ Datetime: POSIXlt, format: "2009-05-03 00:05:12" "2009-05-03 00:05:17" ...

如果您愿意，您现在可以删除 date 和 `time：

> dat <- dat[, -(1:2)]
> head(dat)
    val1 val2            Datetime
1 107.25    1 2009-05-03 00:05:12
2 108.25   20 2009-05-03 00:05:17
3 110.25    5 2009-05-03 00:07:45
4 106.25    5 2009-05-03 00:07:56

You can't do this upon reading the data in to R using the colClasses argument because the data span two "columns" in the CSV file. Instead, load the data and process the date and time columns into a single POSIXlt variable:

dat <- read.csv(textConnection("date,time,val1,val2
                               20090503,0:05:12,107.25,1
                               20090503,0:05:17,108.25,20
                               20090503,0:07:45,110.25,5
                               20090503,0:07:56,106.25,5"))
dat <- within(dat, Datetime <- as.POSIXlt(paste(date, time),
                                          format = "%Y%m%d %H:%M:%S"))

[I presume it is year month day??, If not use "%Y%d%m %H:%M:%S"]

Which gives:

> head(dat)
      date    time   val1 val2            Datetime
1 20090503 0:05:12 107.25    1 2009-05-03 00:05:12
2 20090503 0:05:17 108.25   20 2009-05-03 00:05:17
3 20090503 0:07:45 110.25    5 2009-05-03 00:07:45
4 20090503 0:07:56 106.25    5 2009-05-03 00:07:56
> str(dat)
'data.frame':   4 obs. of  5 variables:
 $ date    : int  20090503 20090503 20090503 20090503
 $ time    : Factor w/ 4 levels "0:05:12","0:05:17",..: 1 2 3 4
 $ val1    : num  107 108 110 106
 $ val2    : int  1 20 5 5
 $ Datetime: POSIXlt, format: "2009-05-03 00:05:12" "2009-05-03 00:05:17" ...

You can now delete date and `time if you wish:

> dat <- dat[, -(1:2)]
> head(dat)
    val1 val2            Datetime
1 107.25    1 2009-05-03 00:05:12
2 108.25   20 2009-05-03 00:05:17
3 110.25    5 2009-05-03 00:07:45
4 106.25    5 2009-05-03 00:07:56

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