[R] How to change the order of columns in a data frame?

jim holtman jholtman at gmail.com
Fri Feb 17 14:44:35 CET 2012


pos2 <- pos1[, c("X", "X1", "X2", "X3", "X4", "X5", "X6", "X7", "X8",
"X9", "X10", "X11", "X12",
      "X13", "X14", "X15", "X16", "X17", "X18", "X19", "X20")]


2012/2/17 Joel Fürstenberg-Hägg <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
>
>        [[alternative HTML version deleted]]
>
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-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.



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