[R] How to rename columns that start with numbers?

[Patrick Connolly]

On Thu, 13-Aug-2009 at 04:24PM -0600, Mark Na wrote:

|> Hello,
|> 
|> My dataframe has new columns that start with the number 1 or 2 (resulting
|> from a reshape cast command).
|> 
|> Instead of having these columns automatically renamed by R so start with the
|> letter X, I would like to rename these columns to start with the characters
|> "SURV_" (e.g., SURV_1, SURV_2).
|> 
|> I can't seen to use grep() to identify and rename the columns starting with
|> either 1 or 2.
|> 
|> Any help would be much appreciated, thanks!
|> 
|> (I know I could rename these manually, but the above is a simpler statement
|> of the actual problem, which involves several dozen columns, so that's why
|> I'd prefer not to so it manually)

Without knowing what your data looked liked before it was reshaped,
it's a bit hard to guess what would be a good way to avoid the
problem, but this might be a case where cure might be easier than
prevention.

If your dataframe has names like these:
> names(junk.df)
[1] "Fruit"    "January"  "February" "X1"       "X2"       "X3"       "X4"      

You can replace each incidence of "X" with "SURV_" this way:

> names(junk.df) <-  gsub("X", "SURV_", names(junk.df))
> names(junk.df)
[1] "Fruit"    "January"  "February" "SURV_1"   "SURV_2"   "SURV_3"   "SURV_4"  

If there are other instances where "X" is a desirable part of the
name, it would be a bit trickier, but not much.

HTH


|> 
|> Mark Na
|> 
|> 	[[alternative HTML version deleted]]
|> 
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   ___    Patrick Connolly   
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