CODEWITHSUNDEEP
rggplot2dataframequotesquoting
remi
remi

Reputation: 779

ggplot handling quoted variable

I run into an unexpected issue in generating a ggplot() plot after operations done to a dataframe. I'm providing an illustrative example:

func <- function(){  
  library(ggplot2)
  df <- read.table(....)

  # Perform operation on df to retrieve column of interest index/number
  column.index <- regexpr(...)   
  # Now need to find variable name for this column
  var.name <- names(df)[column.index]
  # ...also need to mutate data in this column
  df[,column.index] <- df[,column.index] * 10

  # Generate plot
  plot <- ggplot(data, aes(x=var.name))+geom_bar()
  print(plot)
}

Here ggplot will throw an error since var.name is quoted, eg., "mpg". Any idea how to resolve this?

Edit: tested solutions from this question to no avail.

Upvotes: 5

Views: 3772

Answers (2)

smci
smci

Reputation: 33960

Use aes_string, which allows you to pass a string name for the variable.

Upvotes: 6

easports611
easports611

Reputation: 482

You could use the package "dplyr" to re-name the var.name column to something generic (x) and then plot on x:

# also need to mutate data in this column
df[,column.index] <- df[,column.index] * 10
# ***NEW*** re-name column to generic name
df <- rename_(df, .dots=setNames(list(var.name), 'x'))
# generate plot
plot <- ggplot(df, aes(x=x))+geom_bar()

Upvotes: -3

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