Trying to create a data.frame like this:
a = "foo"
bar = data.frame(a = 1:3)
But the name of the column is a, not foo:
> bar
a
1 1
2 2
3 3
The column can be renamed after creating data.frame, but how to easily assign it's name by a variable just in the same data.frame command?
The setNames() function should work for you:
a <- "Numbers"
b <- "Letters"
bar <- setNames(data.frame(1:3, letters[1:3]), c(a, b))
bar
# Numbers Letters
# 1 1 a
# 2 2 b
# 3 3 c
table or data.frame? If b is a data.frame, you could just use setNames(data.frame(1:3, b), c(a, names(b))) (if I understood your question correctly).I don't think you can do what you want to do here because of the way R is interpreting the argument names you supply. Effectively you want get(a) = 1:3 as you want R to take the value of the object stored as a rather than the label a itself, but that idiom is not allowed here.
I would do this:
> a <- "foo"
> bar <- data.frame(1:3)
> names(bar) <- a
>
> bar
foo
1 1
2 2
3 3
bar <- `names<-`(data.frame(1:3),a)
setNames().`names<-`, but I'm not sure why it's not recommended.Try:
a = structure(data.frame(1:3), names="foo")
> a
foo
1 1
2 2
3 3
Slight modification of Daniel Gerlanc's answer using chaining
a <- "foo"
a <- data.frame(1:3) %>% structure(names = c(a))
foo
1 1
2 2
3 3
Chaining is useful when you are creating a data frame from another data type, for example a zoo series,
a <- c("foo","data")
bar
2016-01-01 2016-01-02 2016-01-03 2016-01-04 2016-01-05
0.78 0.46 0.82 1.07 1.04
a <- bar %>% as.data.frame() %>% tibble::rownames_to_column() %>% structure(names=a)
foo data
1 2016-01-01 0.78
2 2016-01-02 0.46
3 2016-01-03 0.82
4 2016-01-04 1.07
5 2016-01-05 1.04
