ggplot for loop outputs all the same graph

Question

I\'ve written a for loop which goes through the columns of a dataframe and produces a graph for each column using ggplot. The problem is the graphs that are output are all t

Answer 1

Here's a more concise way to produce your example:

df <- data.frame(
  Person = paste0("Person", 1:5),
  var1 = c(1,2,3,4,5),
  var2 = c(2,2,2,2,2),
  var3 = c(1,3,5,3,1),
  var4 = c(5,4,3,2,1)
)

Now, about your plots.

Best solution

Reshape the data frame to 'long' format, and then use facets:

library(ggplot2)
library(tidyr)
gather(df, var, value, -Person) %>%
  ggplot(aes(Person, value)) +
    geom_bar(stat = "identity") +
    facet_wrap(~ var)

Otherwise…

If you gotta stick with a data structure that looks like what you posted, then use aes_string:

library(ggplot2)
library(gridExtra)

g <- lapply(1:4, function(i) {

  ggplot(df, aes_string("Person", paste0("var", i))) +
    geom_bar(stat = "identity")

})
grid.arrange(grobs = g, ncol = 2)