[R] Maintaining Column names while writing csv file.

[Eik Vettorazzi]

Hi Vincy,
have you checked

names(df2)

and

names(df_new)

because by default 'data.frame' checks the column names "to ensure that
they are syntactically valid variable names" and 1w and 2w aren't, so an
X is prepended (see ?data.frame and ?make.names).

compare
tst.fail<-data.frame(a=1:3,"1a"=1:3,"1b"=1:3)
names(tst.fail)

#and
tst<-data.frame(a=1:3,"1a"=1:3,"1b"=1:3,check.names = F)
names(tst)

this works for me:

tst2<-data.frame(a=1:3,w1=4:6,w3=4:6)
write.csv(merge(tst,tst2),file="testr.csv")


hth.

Am 19.07.2012 08:55, schrieb Vincy Pyne:
> Dear R helpers,
> 
> I have one trivial problem while writing an output file in csv format.
> 
> I have two dataframes say df1 and df2 which I am reading from two different csv files. 
> 
> df1 has column names as date, r1, r2, r3 while the dataframe df2 has column names as date, 1w, 2w. 
> 
> (the dates in both the date frames are identical also no of elements in each column are equal say = 10).
> 
> I merge these dataframes as
> 
> df_new = merge(df1, df2, by = "date", all = T) 
> 
> So my new data frame has columns as 
> 
> date, r1, r2, r3, 1w, 2w
> 
> However, if I try to write this new dataframe as a csv file as
> 
> write.csv(data.frame(df_new), 'df_new.csv', row.names = FALSE)
> 
> The file gets written, but when I open the csv file, the column names displayed are as
> 
> date, r1, r2, r3, X1w, X2w
> 
> My original output file has about 200 columns so it is not possible to write column names individually. Also, I can't change the column names since I am receiving these files from external source and need to maintain the column names.
> 
> Kindly guide
> 
> 
> Regards
> 
> Vincy
> 
> 
> 	[[alternative HTML version deleted]]
> 
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Eik Vettorazzi

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