Passing argument in a Subset using function in R - r

Question

I want to make a function that will accept a argument and use it into subset and then plot a graph with multiple line. I wrote following code
plot.new( )
rest_o_noise <- function(noise_level, color) {
rest_o_noise_level = subset(yelp_flat, attributes.RestaurantsPriceRange2!= "NA", eval(parse(text=noise_level)))
rest_o_noise_level <- rest_o_noise_level %>%
group_by(attributes.RestaurantsPriceRange2) %>%
summarise(n=mean(stars))
lines(rest_o_noise_level, stars, col=color)
}
rest_o_noise("attributes.NoiseLevel=='loud'", "green")
rest_o_noise("attributes.NoiseLevel=='low'", "green")
I am getting a error:
Error in grouped_df_impl(data, unname(vars), drop) : Column attributes.RestaurantsPriceRange2 is unknown
Just to be clear attributes.RestaurantsPriceRange2 is present in csv.
final output should look like:
Is this correct way to plot?
Please help!!

Answer 1

Getting a subset of rows from iris data using a conditional in a string
Species <- as.character(iris$Species)
noise_level <- "Species == \"setosa\""
subset(iris, Sepal.Length == 5.1 &
eval(parse(text=noise_level)))
# Sepal.Length Sepal.Width Petal.Length Petal.Width Species
# 1 5.1 3.5 1.4 0.2 setosa
# 18 5.1 3.5 1.4 0.3 setosa
# 20 5.1 3.8 1.5 0.3 setosa
# 22 5.1 3.7 1.5 0.4 setosa
# 24 5.1 3.3 1.7 0.5 setosa
# 40 5.1 3.4 1.5 0.2 setosa
# 45 5.1 3.8 1.9 0.4 setosa
# 47 5.1 3.8 1.6 0.2 setosa
In your case, it would be something like what is below which conditions on the
columns attributes.RestaurantsPriceRange2 and attributes.NoiseLevel to select subset of rows.
plot.new( )
rest_o_noise <- function(noise_level, color) {
rest_o_noise_level = subset(yelp_flat,
(attributes.RestaurantsPriceRange2!= "NA") &
eval(parse(text=noise_level)))
rest_o_noise_level <- rest_o_noise_level %>%
group_by(attributes.RestaurantsPriceRange2) %>%
summarise(n=mean(stars))
lines(rest_o_noise_level, stars, col=color)
}
rest_o_noise("attributes.NoiseLevel==\"loud\"", "green")
You can, of course, select a single column, as below. However, why you would use the "==" for that is not clear, hence I assumed you are trying to select a subset of rows.
noise_level <- "Petal.Width"
subset(iris, Sepal.Length == 5.1,
eval(parse(text=noise_level)))
# Petal.Width
# 1 0.2
# 18 0.3
# 20 0.3
# 22 0.4
# 24 0.5
# 40 0.2
# 45 0.4
# 47 0.2
# 99 1.1