Message-ID: <CAM_vju=N3W3LZW-O=G5uuuJ2a7vP=yH9y6Ay=geSZWty1Uf7xw@mail.gmail.com>
Date: 2012-02-17T13:36:27Z
From: Sarah Goslee
Subject: How to change the order of columns in a data frame?
In-Reply-To: <4F3E63AC020000ED00064E90@gwmta2.kvl.dk>
> fakedata <- data.frame(A=c(0,0,0), X2=c(2,2,2), X1=c(1,1,1), X3=c(3,3,3))
> fakedata
A X2 X1 X3
1 0 2 1 3
2 0 2 1 3
3 0 2 1 3
> pos <- colnames(fakedata)[2:ncol(fakedata)]
> pos <- c(1, 1+as.numeric(gsub("X", "", pos)))
> fakedata[, pos]
A X1 X2 X3
1 0 1 2 3
2 0 1 2 3
3 0 1 2 3
>
Sarah
2012/2/17 Joel F?rstenberg-H?gg <joelf at life.ku.dk>:
> Dear all,
>
> I have a data frame in which the columns need to be ordered. The first column X is at the right position, but the remaining columns X1-Xn should be ordered like this: X1, X2, X3 etc instead of like below.
>
>> colnames(pos1)
> ?[1] "X" ? "X1" ?"X10" "X11" "X12" "X13" "X14" "X15" "X16" "X17" "X18" "X19" "X2" ?"X20" "X3" ?"X4" ?"X5" ?"X6" ?"X7" ?"X8" ?"X9"
>
>> pos1[1:5,1:5]
> ? ? ?X ? ? ? X1 ? ? ? X10 ? ? ? X11 ? ? ? X12
> 1 100.5 7949.469 18509.064 ?8484.969 17401.056
> 2 101.5 3080.058 ?7794.691 ?3211.323 ?8211.058
> 3 102.5 1854.347 ?4347.571 ?1783.846 ?4827.338
> 4 103.5 2064.441 ?8421.746 ?2012.536 ?8363.785
> 5 104.5 9650.402 26637.926 10730.647 27053.421
>
> I am trying to first change the first column name to something without an X and save as a vector. I would then remove the X from each position use the vector for renaming the columns. Then the column 2-n could be ordered, I hope...
>
> colnames(pos)[1] <- "Mass"
> columnNames <- colnames(pos)
>
> Does any of you have an idea how to do this, or perhaps there is a smoother solution?
> Would it be easier to solve it if the contents of the first column were extracted and used as row names instead?
>
> Best regards,
>
> Joel
>
--
Sarah Goslee
http://www.functionaldiversity.org