Using match.fun with multiple inputs and filter in R-CodePudding

I have the following database along with a couple of input values:

operator <- ">="
amt <- 600
col <- "salary"

data <- data.frame(
   emp_id = c (1:5), 
   emp_name = c("Rick","Dan","Michelle","Ryan","Gary"),
   salary = c(623.3,515.2,611.0,729.0,843.25)
)

I've used match.fun using the original column name, but want to use the "col" value to specify which column name to filter on, similar to what it'd be below:

data %>% 
   filter(match.fun(operator)(col, amt))

I've tried adding "!!" to the front of col when it's in there, but that doesn't work. If I replace "col" with "salary" in the above table, that does work, but I want to be able to dynamically change what "col" is and have the function react to that.

CodePudding user response：

We may use .data to select the column based on the input col

library(dplyr)
data %>% 
   filter(match.fun(operator)(.data[[col]], amt))

-output

   emp_id emp_name salary
1      1     Rick 623.30
2      3 Michelle 611.00
3      4     Ryan 729.00
4      5     Gary 843.25

Or convert to symbol and evaluate (!!)

data %>% 
 filter(match.fun(operator)(!! rlang::sym(col), amt))
  emp_id emp_name salary
1      1     Rick 623.30
2      3 Michelle 611.00
3      4     Ryan 729.00
4      5     Gary 843.25

Or another option is to pass it in across

data %>% 
   filter(across(all_of(col), ~ match.fun(operator)(.x, amt)))
  emp_id emp_name salary
1      1     Rick 623.30
2      3 Michelle 611.00
3      4     Ryan 729.00
4      5     Gary 843.25

Or another option is to create an expression with paste/str_c and then parse

library(stringr)
data %>% 
  filter(!!rlang::parse_expr(str_c(col, operator, amt)))
  emp_id emp_name salary
1      1     Rick 623.30
2      3 Michelle 611.00
3      4     Ryan 729.00
4      5     Gary 843.25