tibble preserves names attribute of added vector in column (and as.data.frame preserves as well)

[ghost]

I wonder whether a tibble should preserve a vector's names attribute when added as a column or not. A data frame drops this attribute when a column is added.

?tibble might contain a hint that this is intended behaviour, but it is not clear from that ("tibble() is much lazier than base::data.frame() in terms of transforming the user's input. Character vectors are not coerced to factor. List-columns are expressly anticipated and do not require special tricks. Column names are not modified.").

See the example below about the difference in behaviour.

I would "vote" mimicing base R data frame's behaviour here.

At least when converting back to data frame via as.data.frame.tbl_df the names attribute should be pruned from columns.

library(tibble)
a <- 1:5
b <- 6:10
names(b) <- letters[1:5]

df <- data.frame(a, a * 2)
tb <- tibble(df)

df$b <- b
tb$b <- b

lapply(df, names) # data frame's columns do not have names
#> $a
#> NULL
#> 
#> $a...2
#> NULL
#> 
#> $b
#> NULL
lapply(tb, names) # tibble's column b preserved names
#> $a
#> NULL
#> 
#> $a...2
#> NULL
#> 
#> $b
#> [1] "a" "b" "c" "d" "e"

df_tb <- as.data.frame(tb)
lapply(df_tb, names) # data frame's column b has names - illegal data frame?
#> $a
#> NULL
#> 
#> $a...2
#> NULL
#> 
#> $b
#> [1] "a" "b" "c" "d" "e"

[krlmlr]

Thanks. This has been added in tibble 3.0.0 as an experimental feature.

[ghost]

Thank you for clarification that this is intended for a tibble. What about as.data.frame.tbl_df though? Shouldn't that produce a data frame withouth "inner names" as such a data frame cannot be generated by default data frame methods?

[krlmlr]

I missed that part. Can you show an example where this is important?

[ghost]

It led to a hiccup in data processing of a package, see here https://stackoverflow.com/a/65646743/4640346, as the package did not cater for the case when there are names in columns (why should it? a data frame does not have them). Data was pruned by as.data.frame before processing.
Further - and only slightly related - see this PR#18034 about R https://bugs.r-project.org/bugzilla/show_bug.cgi?id=18034

[krlmlr]

Let's remove inner names in as.data.frame.tbl_df() .

[krlmlr]

Done now, also tweaked documentation.

[github-actions]

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