could not find function "bitr"

The error message "could not find function 'bitr'" usually means that the 'bitr' function is not available in the current environment. This could be due to a variety of reasons, such as the package that contains the function not being loaded, or the function not being installed on your system.

To resolve this issue, you may need to install the package that contains the 'bitr' function using the 'install.packages' function in R. For example, if the 'bitr' function is part of the 'bitops' package, you could install it by running the following command:

install.packages("bitops")

Once the package is installed, you can load it into your R session using the 'library' function:

library(bitops)

This should make the 'bitr' function available for use in your code.