如何用子串替换多个列名称

Question

我想用substring（）编辑多个列名称。只有我写的代码不起作用。

奇怪的是下面的代码有效。 旧列名：

oldColNames <- names(forcesdf[,c(5:20)]) 

结果：

> names(forcesdf[,c(5:20)]) 
[1] "2000 [YR2000]" "2001 [YR2001]" "2002 [YR2002]" "2003 [YR2003]" "2004 [YR2004]" "2005 [YR2005]" "2006 [YR2006]" 
[8] "2007 [YR2007]" "2008 [YR2008]" "2009 [YR2009]" "2010 [YR2010]" "2011 [YR2011]" "2012 [YR2012]" "2013 [YR2013]" 
[15] "2014 [YR2014]" "2015 [YR2015]" 

而新的列名：

newColNames <- substring(names(forcesdf[,c(5:20)]), 1, 4) 
oldColNames <- newColNames 

结果我excually想：

> oldColNames 
[1] "2000" "2001" "2002" "2003" "2004" "2005" "2006" "2007" "2008" "2009" "2010" "2011" "2012" "2013" "2014" "2015" 

中当然，我想改变我的数据框中的列名，所以最初，我写了下面的代码，但名称没有改变。

names(forcesdf[,c(5:20)]) <- substring(names(forcesdf[,c(5:20)]), 1, 4) 

> names(forcesdf[,c(5:20)]) 
[1] "2000 [YR2000]" "2001 [YR2001]" "2002 [YR2002]" "2003 [YR2003]" "2004 [YR2004]" "2005 [YR2005]" "2006 [YR2006]" 
[8] "2007 [YR2007]" "2008 [YR2008]" "2009 [YR2009]" "2010 [YR2010]" "2011 [YR2011]" "2012 [YR2012]" "2013 [YR2013]" 
[15] "2014 [YR2014]" "2015 [YR2015]" 

Answer 1

测试此

names(forcesdf)[5:20] <- substring(names(forcesdf[,c(5:20)]), 1, 4) 

Answer 2

如果你这样做你可以改变他们：

names(forcesdf)[5:20] <- substring(names(forcesdf)[5:20], 1, 4) 

我觉得关键是在你的代码进行子集列名，但不能引用到他们。