I'd like to copy a set of variables in my tibble so I can have variable_unmodified and variable values in downstream evaluation. I've come up with a hacky version using the old-style underscore NSE select_() function and .dots, but would like to use the newer NSE approach of tidy evaluation semantics.
This does what I want:
tibble_to_max <- tibble(
"a_col" = c("1", "2", "3", "4"),
"max_1" = c("3;4", "2{3}4", "7", ".{1}"),
"max_2" = c("3;4", "2{3}4", "7", ".{1}")
)
cols_to_max <- c("max_1", "max_2")
unparsed_names <- paste0(cols_to_max, "_unparsed")
tibble_to_max %>%
bind_cols(select_(., .dots = setNames(cols_to_max, unparsed_names)))
output:
# A tibble: 4 x 5
a_col max_1 max_2 max_1_unparsed max_2_unparsed
<chr> <chr> <chr> <chr> <chr>
1 1 3;4 3;4 3;4 3;4
2 2 2{3}4 2{3}4 2{3}4 2{3}4
3 3 7 7 7 7
4 4 .{1} .{1} .{1} .{1}
But if I try to do it with select() and !!, .dots doesn't work as I expected:
tibble_to_max %>%
bind_cols(select(., .dots = setNames(!!cols_to_max, !!unparsed_names)))
The columns are not named as desired:
# A tibble: 4 x 5
a_col max_1 max_2 .dots1 .dots2
<chr> <chr> <chr> <chr> <chr>
1 1 3;4 3;4 3;4 3;4
2 2 2{3}4 2{3}4 2{3}4 2{3}4
3 3 7 7 7 7
4 4 .{1} .{1} .{1} .{1}
What is the correct way to do this? Also, bonus points for avoiding defining unparsed_names as a separate variable...
Thanks to @CPak for getting me on the right path. This accomplishes what I was shooting for, and uses tidy evaluation semantics instead of select_():
tibble_to_max <- tibble(
"a_col" = c("1", "2", "3", "4"),
"max_1" = c("3;4", "2{3}4", "7", ".{1}"),
"max_2" = c("3;4", "2{3}4", "7", ".{1}")
)
cols_to_max <- c("max_1", "max_2")
tibble_to_max %>%
bind_cols(
select_at(.,
.vars = !!cols_to_max,
.funs = funs(paste0(., "_unparsed"))
)
)