Dear R-help,

I am trying to rename the variables in a dataframe, called 'T1A' here.
Seems renaming was successful, but when I call one of the variable I got
error message and I wanted to know why.


The data frame contains 365 rows and 49 columns. I would like to name the
first column `DATE` and the others T0.5, T1, T1.5,...,T24 (as this is a set
of data collected every half hour for a whole year).

Original data is saved as csv file and column 2-49 are named in format
'00:30,01:00,01:30,...,23:30,00:00'. When I read them into R by using
read.csv, the column names are changed automatically as 'X0.30.00,
X1.00.00,...,X23.30.00,X0.00.00' , which dont look great (i mean I would
prefer it in a format as 'hh:mm', NOT using 'dot' between numbers that used
to indicate time, but I have not found a solution...). So I decided to use
a simplified version as above, e.g. T0.5, T1, T1.5,...,T24 and my code is:


TIME<-paste(rep("T",48),as.character(seq(0.5,24,by=0.5)))
names(T1A)<-c("DATE",TIME)

> class(T1A$T0.5)  ## without a space between 'T' and '0.5'
[1] "NULL"
> class(T1A$T 0.5)  ## with a space between 'T' and '0.5'
Error: unexpected numeric constant in "class(T1A$T 0.5"


I also tried the code below, but got same error message...

 TIME<-paste(rep("T",48),seq(0.5,24,by=0.5))
names(T1A)<-c("DATE",TIME)


However, if I do not change the columns' name then everything works
fine, e.g. I can call the variables with no problem.

class(T1A$X00.30.00)
[1] "numeric"

Any thoughts??


Many thanks!!!
HJ

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