如何删除R数据帧中部分列标题

Question

我有一个包含以下列名的数据框：

R > colnames(crime)

 [1] "http...purl.org.linked.data.sdmx.2009.dimension.refArea"
 [2] "Reference.Area"                                         
 [3] "X1996.1997"                                             
 [4] "X1997.1998"                                             
 [5] "X1998.1999"                                             
 [6] "X1999.2000"                                             
 [7] "X2000.2001"                                             
 [8] "X2001.2002"                                             
 [9] "X2002.2003"                                             
[10] "X2003.2004"                                             
[11] "X2004.2005"                                             
[12] "X2005.2006"                                             
[13] "X2006.2007"                                             
[14] "X2007.2008"                                             
[15] "X2008.2009"                                             
[16] "X2009.2010"                                             
[17] "X2010.2011"                                             
[18] "X2011.2012"                                             
[19] "X2012.2013"                                             
[20] "X2013.2014"                                             
[21] "X2014.2015"                                             
[22] "X2015.2016"                                             
[23] "X2016.2017"                                             
[24] "X2017.2018" 

我还有一篇专栏文章：

R > crime[,1]
 [1] http://statistics.gov.scot/id/statistical-geography/S12000033
 [2] http://statistics.gov.scot/id/statistical-geography/S12000034
 [3] http://statistics.gov.scot/id/statistical-geography/S12000041
 [4] http://statistics.gov.scot/id/statistical-geography/S12000035
 [5] http://statistics.gov.scot/id/statistical-geography/S12000036
 [6] http://statistics.gov.scot/id/statistical-geography/S12000005
 [7] http://statistics.gov.scot/id/statistical-geography/S12000006

我想要的是第一个列名是"refArea“，年份是最后4个数字，即"X1996.1997“将是"1997”。我也希望第一列只包含最后9个字符(例如S12000006 -代码不同，有些是S02……或S01...)

我当前的代码如下：

R > colnames(crime)[colnames(crime) == "http...purl.org.linked.data.sdmx.2009.dimension.refArea"] <- "refArea" #replace url with "refArea"

crime$refArea <- substr(crime$refArea, 53, 61) #substring only characters 53-61 from column refArea

colnames(crime) <- c("refArea", "Reference.Area", "1997", "1998", "1999", "2000", "2001", "2002", "2003", "2004", "2005", "2006", "2007", "2008", "2009", "2010", "2011", "2012", "2013", "2014", "2015", "2016", "2017", "2018") #Manually change column names

但这感觉非常笨拙和糟糕的编码(我必须对8或9个以上的数据集重复此过程)-您将如何改进这一点？

Answer 1

一个选项是sub，用于捕获'refArea‘并删除所有前面的字符。要从'X1996.1997‘中删除"X1996“，我们可以使用substr

colnames(crime)[1] <- sub(".*\\.(refArea)", "\\1", colnames(crime)[1])
v1 <-  colnames(crime)[3:ncol(crime)] 
colnames(crime)[3:ncol(crime)] <- substr(v1, nchar(v1)-3, nchar(v1))