CODEWITHSUNDEEP
rtidyverserlang
H5470
H5470

Reputation: 91

How to fix 'Quosures can only be unquoted within a quasiquotation context' error in R function

I am trying to write my first function using rlang and I am having some trouble fixing the following error.

I've read the vignette, but didn't see a good example of what I'm trying to do.

library(babynames)
library(tidyverse)

name_graph <- function(data, name, sex){
name <- enquo(name)
sex <- enquo(sex)

data %>%
  filter_(name == !!name, sex == !!sex) %>%
  select(year, prop) %>%
  ggplot()+
  geom_line(mapping = aes(year, prop))
}

name_graph(babynames, Robert, M)

I'm expecting my distribution graph, but getting an error:

Called from: abort(paste_line("Quosures can only be unquoted within a quasiquotation context.", "", " # Bad:", " list(!!myquosure)", "", " # Good:", " dplyr::mutate(data, !!myquosure)"))

Upvotes: 4

Views: 3943

Answers (2)

akrun
akrun

Reputation: 886928

We can modify the function by converting the quosures (enquo) to string in the filter

library(rlang)
library(dplyr)
library(ggplot2)
name_graph <- function(data, name, sex){
   name <- enquo(name)
   sex <- enquo(sex)

    data %>%
      filter(name == !! as_label(name), sex == !! as_label(sex)) %>%
      select(year, prop) %>%
      ggplot()+
              geom_line(mapping = aes(year, prop))
    }

name_graph(babynames, Robert, M)

enter image description here

Upvotes: 8

Cettt
Cettt

Reputation: 11981

the function filter_is deprecated and you should try avoid using it. Also dplyr::filter doesn't work well if the variable name is the same as the input.

Try this:

name_graph <- function(data, myname, mysex){

data %>%
  filter(name == myname, sex == mysex) %>%
  select(year, prop) %>%
  ggplot()+
  geom_line(mapping = aes(year, prop))
}

Also, as mentioned in the comments, quosures are used if you try passing column names as input arguments. In your case you are passing character strings as inputs so you do not need quosures and it's better not to use them in your case.

Upvotes: 3

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