how to pass the strings with quotes as function arguments values-CodePudding

I am facing issue as below where I am unable to use the string with quotes as a function argument value, here is program where i am creating a simple function to subset the data based on the string subset condition as below. I am using the rlang package curly curls {{ but this seems not working any thoughts

adsl <- data.frame(SubjList=c(1:10), SAFFL=sample(c('Y','N'),10,replace = T))

subs <- function(data=NA,subset='SubjList!=""'){
data1 <- data %>% filter({{subset}})
  return(data1)
}

subs(data=adsl,subset = "SAFFL=='Y'")

CodePudding user response：

Edit

One solution is to use the parse_expr() function from the rlang package (https://rlang.r-lib.org/reference/parse_expr.html) and the bang-bang operator:

library(tidyverse)
library(rlang)

adsl <- data.frame(SubjList=c(1:10),
                   SAFFL=sample(c('Y','N'),10,
                                replace = T))

subs <- function(data, subset) {
  data1 <- data %>% filter(!!parse_expr((subset)))
  return(data1)
}

subs(data = adsl, subset = 'SAFFL == "Y"')
#>   SubjList SAFFL
#> 1        1     Y
#> 2        3     Y
#> 3        4     Y
#> 4        5     Y
#> 5        6     Y
#> 6        7     Y
#> 7       10     Y

^{Created on 2022-11-30 with reprex v2.0.2}

Original answer

One potential solution is to specify the variable (i.e. "SAFFL") and the value ("Y" or "N") separately, e.g.

library(tidyverse)

adsl <- data.frame(SubjList=c(1:10),
                   SAFFL=sample(c('Y','N'),10,
                                replace = T))

subs <- function(data, var, value){
  data1 <- data %>% filter(.data[[var]] == value)
  return(data1)
}

subs(data = adsl, var = "SAFFL", value = "Y")
#>   SubjList SAFFL
#> 1        4     Y
#> 2        5     Y
subs(data = adsl, var = "SAFFL", value = "N")
#>   SubjList SAFFL
#> 1        1     N
#> 2        2     N
#> 3        3     N
#> 4        6     N
#> 5        7     N
#> 6        8     N
#> 7        9     N
#> 8       10     N

^{Created on 2022-11-30 with reprex v2.0.2}

Does that work for your use-case? Or do you need to pass the variable and the value together for some reason?