Iterate over a categorical and a numerical data frames and ploting a bar chart in r

user_12848857 0
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I have a numeric data frame call A and a categoriacal one call B For every two variables (one from B and one from A) I want to plot a bar chart.

My try:

y <- unlist(lapply(D, Negate(is.numeric)))
x <- unlist(lapply(D, is.numeric))    
A <- D[,x]
B <- D[,y]
A <- as.data.frame(A)
B <- as.data.frame(B)

for(i in (1:ncol(A)))
{
  for(j in (1:ncol(B)))
  {
    ggplot(D, aes(x = A[,i], y = B[,j])) +
    geom_bar(fill='red') 
  }
}

But is not plotting anything. I'm not sure if it's necessary to save each plot in a vector and then plot them with another for. Any suggestions would be great!

ggplot2 dataframe bar-chart r for-loop
2 Answers

You will need to wrap the ggplot statement inside the print() function to generate output while inside a loop:

for(i in (1:ncol(A)))
{
  for(j in (1:ncol(B)))
  {
    g<- ggplot(D, aes(x = A[,i], y = B[,j])) +
             geom_bar(fill='red') 
    print(g)
  }
}
user_57922440

I think you need to replace geom_bar() with geom_col() or to add stat = identity inside geom_bar().

You can also avoid using the for loop by using pmap from package purrr:

 df <- expand.grid(
    i = 1:ncol(A),
    j = 1:ncol(B)
)

purrr::pmap(
    list(df$i, df$j),
    function(.i, .j){
        tmp <- ggplot(D, aes(x = A[,.i], y = B[,.j])) +
            geom_col(fill='red')
        print(tmp)
    }
)

I should also add that you can assign the result of pmap to an object (e.g. p) and then call each charts using p[[k]].

user_57907130
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