R中带有as.date的新变量

这是

head（都是$stterm）

正如我所说，这只是数据集的一部分，我有4021个观测值。我想创建一个新列，每个日期代表一个值，如下所示

变量应该是连续的

我已经测试了as.date，但是我刚刚得到一个满是NULL的列

重要的是，它是2008-09-01=8，而不是08

"2007-09-01"=7,
"2008-09-01"=8,
"2009-01-19"=9,
"2009-09-01"=9,
"2010-01-19"=10,
"2010-09-01"=10,
"2011-01-19"=11,
"2011-09-01"=11,
"2012-01-19"=12,
"2012-09-01"=12,
"2013-01-19"=13,
"2013-09-01"=13,
"2014-01-19"=14)

所以我想做的只是创建一个数字列，而不是实际日期。 新变量将被调用：

日历年。

---

我需要关于如何在R中写入此内容的提示。您可以按如下方式执行此操作：

require(lubridate)
dat$year <- year(as.Date(dat$stterm))-2000

数据：

---

dat您可以按如下方式执行此操作：

require(lubridate)
dat$year <- year(as.Date(dat$stterm))-2000

数据：

dat尝试
lubridate
库

install.packages(lubridate)
library(lubridate)
year(ymd(both$stterm))-2000

请尝试使用lubridate
库

install.packages(lubridate)
library(lubridate)
year(ymd(both$stterm))-2000

你可以试试这个

d <- as.Date(c("2007-09-01", "2008-09-01", "2009-01-19", "2009-09-01", "2010-01-19", "2010-09-01", "2011-01-19", "2011-09-01", "2012-01-19", "2012-09-01", "2013-01-19", "2013-09-01", "2014-01-19"), format="%Y-%m-%d")
sub("^0", "", sub("[[:digit:]]{2}([[:digit:]]{2}).*", "\\1", d))
 [1] "7"  "8"  "9"  "9"  "10" "10" "11" "11" "12" "12" "13" "13" "14"

d你可以试试这个

d <- as.Date(c("2007-09-01", "2008-09-01", "2009-01-19", "2009-09-01", "2010-01-19", "2010-09-01", "2011-01-19", "2011-09-01", "2012-01-19", "2012-09-01", "2013-01-19", "2013-09-01", "2014-01-19"), format="%Y-%m-%d")
sub("^0", "", sub("[[:digit:]]{2}([[:digit:]]{2}).*", "\\1", d))
 [1] "7"  "8"  "9"  "9"  "10" "10" "11" "11" "12" "12" "13" "13" "14"

d您可以尝试使用基本R执行此操作：
首先要复制数据集的子集：

both <- data.frame( stterm=as.Date(c('2011-01-19','2012-01-19', '2007-09-01','2011-09-01','2008-09-01','2013-09-01')))

both
      stterm
1 2011-01-19
2 2012-01-19
3 2007-09-01
4 2011-09-01
5 2008-09-01
6 2013-09-01

both$calenderyear <- as.numeric(format(both$stterm,"%y"))
both
      stterm calenderyear
1 2011-01-19           11
2 2012-01-19           12
3 2007-09-01            7
4 2011-09-01           11
5 2008-09-01            8
6 2013-09-01           13

两个您可以尝试使用base R执行此操作：
首先要复制数据集的子集：

both <- data.frame( stterm=as.Date(c('2011-01-19','2012-01-19', '2007-09-01','2011-09-01','2008-09-01','2013-09-01')))

both
      stterm
1 2011-01-19
2 2012-01-19
3 2007-09-01
4 2011-09-01
5 2008-09-01
6 2013-09-01

both$calenderyear <- as.numeric(format(both$stterm,"%y"))
both
      stterm calenderyear
1 2011-01-19           11
2 2012-01-19           12
3 2007-09-01            7
4 2011-09-01           11
5 2008-09-01            8
6 2013-09-01           13

两者