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")
应用as.Date
到Date
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
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 -
df
日期作为因子的as_tibble()
数据帧将它转换到tidyverse tibble格式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...