I can calculate the rank of the values ( val
) in my dataframe df
within the group name1
with the code:
res <- df %>% arrange(val) %>% group_by(name1) %>% mutate(RANK=row_number())
Instead of writing the column "name1" in the code, I want to pass it as variable, eg crit = "name1"
. However, the code below does not work since crit1
is assumed to be the column name instead of a variable name.
res <- df %>% arrange(val) %>% group_by(crit1) %>% mutate(RANK=row_number())
How can I pass crit1
in the code?
Thanks.
We can use group_by_
library(dplyr)
df %>%
arrange(val) %>%
group_by_(.dots=crit1) %>%
mutate(RANK=row_number())
#Source: local data frame [10 x 4]
#Groups: name1, name2 [7]
# val name1 name2 RANK
# <dbl> <chr> <chr> <int>
#1 -0.848370044 b c 1
#2 -0.583627199 a a 1
#3 -0.545880758 a a 2
#4 -0.466495124 b b 1
#5 0.002311942 a c 1
#6 0.266021979 c a 1
#7 0.419623149 c b 1
#8 0.444585270 a c 2
#9 0.536585304 b a 1
1#0 0.847460017 a c 3
group_by_
is deprecated in the recent versions (now using dplyr
version - 0.8.1
), so we can use group_by_at
which takes a vector of strings as input variables
df %>%
arrange(val) %>%
group_by_at(crit1) %>%
mutate(RANK=row_number())
Or another option is to convert to symbols ( syms
from rlang
) and evaluate ( !!!
)
df %>%
arrange(val) %>%
group_by(!!! rlang::syms(crit1)) %>%
mutate(RANK = row_number())
set.seed(24)
df <- data.frame(val = rnorm(10), name1= sample(letters[1:3], 10, replace=TRUE),
name2 = sample(letters[1:3], 10, replace=TRUE),
stringsAsFactors=FALSE)
crit1 <- c("name1", "name2")
The new across
syntax eliminates the need for !!! rlang::syms()
!!! rlang::syms()
. So you can now simplify the code by:
df %>%
arrange(val) %>%
group_by(across(all_of(crit1))) %>%
mutate(RANK = row_number())
Facing a similar task I could successfully work with these two options.
Use across()
:
for (crit in names(df)) {
print(df |>
# all_of() is not needed here
group_by(across(crit)) |>
count())
}
Use syms()
and !!
:
crits = syms(names(df))
for (crit in crits) {
print(df |>
# the use of !! instead of !!! is now encouraged
group_by(!!crit) |>
count())
}
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