Using dplyr filter() in programming

user_4351039 0
Viewed 1883

I am writing my function and want to use dplyr's filter() function to select rows of my data frame that satisfy a condition. This is my code:

library(tidyverse)

df <-data.frame(x = sample(1:100, 50), y = rnorm(50), z = sample(1:100,50), w = sample(1:100, 50),
            p = sample(1:100,50))

new <- function(ang,brad,drau){
  df%>%filter(!!drau %in% 1:50)%>%select(ang,brad) -> A
return(A)
}

brand <- c("z","w","p")
lapply(1:3, function(i) new(ang = "x", brad = "y", drau = brand[i]))%>%bind_rows()

Anytime I run this function, it looks like filter doesn't select any rows that satisfy the condition.

How can I make this work?

Update

For some reason, this works when I don't use `%in%, as in;

new <- function(ang,brad,drau){
  df%>%filter(!!drau > 50)%>%select(ang,brad) -> A
return(A)
}

lapply(1:3, function(i) new(ang = "x", brad = "y", drau = brand[i]))%>%bind_rows()

However, the results are the same for every loop. Why is this so? and also why can't I use %in%.

rlang dplyr tidyverse r
4 Answers

With UQE now deprecated, the accepted answer for this question will not work. This answer should work. The only change here is !!sym()

library(rlang)
library(tidyverse)

df <-data.frame(x = sample(1:100, 50), y = rnorm(50), z = sample(1:100,50), w = sample(1:100, 50),
                p = sample(1:100,50))

new <- function(ang,brad,drau){
  df%>%filter(!!sym(drau) %in% 1:50)%>%select(!!sym(ang), !!sym(brad)) -> A
  return(A)
}

brand <- c("z","w","p")
lapply(1:3, function(i) new(ang = "x", brad = "y", drau = brand[i]))%>%bind_rows()

If you want do not want to pass your function arguments as strings, use !!enquo() instead.

new <- function(ang,brad,drau){
  df%>%filter(!!enquo(drau) %in% 1:50)%>%select(!!enquo(ang), !!enquo(brad)) -> A
  return(A)
}

> head(new(ang = x, brad = y, drau = z))
    x           y
1  44  0.47702540
2  84 -1.09670409
3  59 -0.20556334
4  81 -0.46306635
5  93  1.36845485
6   8  0.37392587
user_43510390

I had a similar issue, and the simple fix that worked for me was to use the ".data" pronoun within the "filter" verb, specifically in this context:

filter(.data[[drau]] %in% 1:50)

More info here: https://tinyheero.github.io/2020/03/01/use-data-env-pronouns-tidyverse.html Also recent talks by Lionel Henry on Rstudio's youtube channel are helpful too.

library(tidyverse)

df <-data.frame(x = sample(1:100, 50), y = rnorm(50), z = sample(1:100,50), w = sample(1:100, 50),
                p = sample(1:100,50))

new <- function(ang,brad,drau){
  df%>%filter(.data[[drau]] %in% 1:50)%>%select(ang,brad) -> A
  return(A)
}

brand <- c("z","w","p")
lapply(1:3, function(i) new(ang = "x", brad = "y", drau = brand[i]))%>%bind_rows()

Hope someone finds some use in this.

user_139827120
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