CSV file: Error in -0.01 * height : non-numeric argument to binary operator in R

Question

species 0 30 nM 100nM
MeHg  -14.78  -21.66  -20.41
<1 kDa  -13.33  -15.41  -16.68
1-3 kDa -14.66  -15.29  -15.35
3-10 kDa  -15.71  -17.19  -17.73
10-100 kDa  -16.77  -17.57  -17.77
100 kDa-700 nm  -23.46  -23.76  -21.62

This is my matrix in csv file, I want to draw multiple barplot in R.

Data <- read.csv ("Book1.csv", header=T)
Data2<-as.matrix(Data)
barplot <-(Data2, main="abc", xlab="a", ylab="b", beside=T)

It shows

Error in -0.01 * height : non-numeric argument to binary operator.

I do not know how to change the code

Answer 1

I think you are attempting to pass arguments to barplot using <-. That's just not how R handles functional parameters. Furthermore, barplot takes either a single numeric vector of values, or a numeric matrix. You've given it a character matrix, since that first column could only be a character vector and matrices need to have all of their columns of the same storage type. Hence, the error about "non-numeric argument". Instead, skip the step where you convert to a matrix and instead leave the first column out using a negative index:

barplot( data.matrix(dat[-1]), main="abc", xlab="a", ylab="b", beside=T)