季度数据 - 转换系数为日期

问题描述 投票:0回答:2

无法日期列从要素转换为日期类型。我试过基础R和lubridate策略:

> as.Date(df)
Error in as.Date.default(x, ...) : 
  do not know how to convert 'x' to class “Date”

> yq(df)
[1] NA
Warning message:
All formats failed to parse. No formats found. 

数据:

df<- structure(list(Date = structure(c(1L, 1L, 1L, 1L, 1L, 1L), .Label = c("2008-07-31", 
"2009-07-31", "2010-07-31", "2011-07-31", "2012-07-31", "2013-07-31", 
"2014-07-31", "2011-10-31", "2012-10-31", "2013-10-31", "2014-10-31", 
"2016-10-31", "2017-10-31"), class = "factor")), row.names = c(NA, 
6L), class = "data.frame")
r date lubridate posixct
2个回答
1
投票

应用as.DateDate列,而不是整个data.frame。没有软件包使用。

transform(df, Date = as.Date(Date))

赠送:

        Date
1 2008-07-31
2 2008-07-31
3 2008-07-31
4 2008-07-31
5 2008-07-31
6 2008-07-31

0
投票

上面的回答表明,基础R的方法来你的问题。我已经使用了tidyverse包做同样的事情,就像做事情的方式不同。

首先,我们来看看你的数据

df<- structure(list(Date = structure(c(1L, 1L, 1L, 1L, 1L, 1L), .Label = c("2008-07-31", 
"2009-07-31", "2010-07-31", "2011-07-31", "2012-07-31", "2013-07-31", 
"2014-07-31", "2011-10-31", "2012-10-31", "2013-10-31", "2014-10-31", 
"2016-10-31", "2017-10-31"), class = "factor")), row.names = c(NA, 
6L), class = "data.frame")

print(df)

        Date
1 2008-07-31
2 2008-07-31
3 2008-07-31
4 2008-07-31
5 2008-07-31
6 2008-07-31

如果我们看一下数据帧的结构,我们可以看到日期存储为因素

str(df)

'data.frame':   6 obs. of  1 variable:
 $ Date: Factor w/ 13 levels "2008-07-31","2009-07-31",..: 1 1 1 1 1 1

我们需要加载一些库。需要说明的唯一的一个是magrittr包,其提供方便%<>%运算符,它指定在管道上的右侧的操作的结果到原来的可变

library(tidyverse)
library(lubridate)
library(magrittr)

因此,在下面的管道,我们 -

  • 管通过df日期作为因子的as_tibble()数据帧将它转换到tidyverse tibble格式
  • 然后使用mutate功能覆盖Date列,
  • lubridate功能ymd,这是一个方便的功能,它分析中因子或字符串格式的日期在一个year-month-date结构的结果替换它的值。如果数据是在dmy格式的等效可能是day-month-year
df %<>%
  as_tibble() %>%
  mutate(
    Date = ymd(Date)
  )

现在做到这一点,我们可以看一下数据

print(df)
# A tibble: 6 x 1
  Date      
  <date>    
1 2008-07-31
2 2008-07-31
3 2008-07-31
4 2008-07-31
5 2008-07-31
6 2008-07-31

现在,您可以看到日期现在存储作为date数据类型。

最后的评论 -

如果你想要做手工创建数据表或tibbles的,看看在tribble功能如下,我们手动创建相同tibble像你一样,再抹上数据类型factor

df <- tribble(
    ~Date,
    "2008-07-31", 
    "2009-07-31", 
    "2010-07-31", 
    "2011-07-31", 
    "2012-07-31", 
    "2013-07-31", 
    "2014-07-31", 
    "2011-10-31", 
    "2012-10-31", 
    "2013-10-31", 
    "2014-10-31", 
    "2016-10-31", 
    "2017-10-31") 


df %<>%
  mutate(
    Date = as_factor(Date)
  )

glimpse(df)

Observations: 13
Variables: 1
$ Date <fct> 2008-07-31, 2009-07-31, 2010-07-31, 2011-07-31, 2012-07-31, 2013-07-31, 2014-07-31, 2011-10-31, 2012-10-31, 2013-10-31, 2014-10-31...
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