[R] column names in data.frame

[Louize Hill]

Dear R-help,
Please can someone explain how to put a column name on an output data.frame.

##Starting with a data.frame with 3 columns (d$Year, d$NoIndiv, d$wtd_tl)

yr_ind <- split (d$NoIndiv, d$Year)
yr_tl <- split (d$wtd_tl, d$Year)

ann_ind <- sapply (yr_ind, sum)
ann_tl <- sapply (yr_tl, sum)

av_tl <- ann_tl/ann_ind

d2<- data.frame (av_tl)

##This gives me a data.frame with columns, the second of which has a column
name (av_tl)
I have tried
> d2<- data.frame (year = x, av_tl)
> d2<- data.frame (x="year", av_tl)
> d2<- data.frame (x="year", av_tl, check.names = TRUE)
> d2<- data.frame (year, av_tl)

as well as several combinations with cbind, as.matrix, etc...
I cannot relate the examples given in ?data.frame with my problem or find a
similar problem in the archives.
Thanks
Louize