Question

Thanks in advance for your response.
I am trying to create a stacked bar plot from a csv file, and I have run into the following hiccup:
First I put the csv into a variable:

test <- read.csv(file=\"test4.csv\",sep=\",\",head=TRUE")

Then I try to create a bar plot using the following

barplot(test)

and I get the following error,

Error in barplot.default(test) : 'height' must be a vector or a matrix

so I try

barplot(t(test))

and it works but as expected the axis are switched, so I try

barplot(t(t(test)))

and it works, but I feel there must be a better solution than transposing the transposed.

Answer 1

The issue is that read.csv outputs a data frame and barplot expects either a vector or a matrix. The barplot function works when you transpose because t() coerces data frames to matrices.

If you either start with

test <- as.matrix(read.csv(file="test4.csv",sep=",",head=TRUE))

or later on do

barplot(as.matrix(test))

then you should be fine.