Error: could not find function … in R

The possible reasons for getting r could not find function error solved are as follows:

You did not spell the function name correctly.

The function is contained in a library which is not installed.

The library of the function is not loaded with either library() or require().

The version of R you are using is obsolete where that function does not exist.

You can use the following code to check the package in which the function is contained:

help.search("function_name") or ??function_name
 To find the function, use the following functions:
find(function_name)

OR

    getAnywhere(function_name)

You can also use the findFn from the sos package to display the packages containing the function as follows:

    install.packages("sos") library("sos") findFn("function_name")

It will open a web page that will show all the libraries where the function is contained.