error message when doing iteration with ggplot2:"More than one expression parsed"

Question

I have a data frame with 8 variables, I tried to plot bar plots of 3 variables(discrete variables) in one page using the following script:

lyst <- list(colnames(mydata[3:5]))
pl<-lapply(lyst, function(i)ggplot(mydata, aes_string(i)) + geom_bar(aes_string(fill=i)))
marrangeGrob(pl, nrow=2, ncol=2)

At first it worked, but now I get the following error message: Error: More than one expression parsed Call rlang::last_error() to see a backtrace.

rlang::last_error() More than one expression parsed Backtrace:

1. base::lapply(...)

2. global::FUN(X[[i]], ...)

3. ggplot2::aes_string(i)

4. base::lapply(...)

5. ggplot2:::FUN(X[[i]], ...)

6. rlang::parse_expr(x).

Any one have an idea how to fix this error?

Answer 1

For me, the column names of my dataframe contained unwanted characters like semicolons and white spaces. To fix this problem, I cleaned the column names before passing them as strings to aes_string(). You can do this with base r's make.names() function or using janitor::clean_names() before running your code.

Solution:

# Using base r:

colnames(mydata) <- make.names(colnames(mydata))

# Using Janitor:

install.packages(janitor) # If not already installed

mydata <- janitor::clean_names(mydata)