Bug decoder for R beginners

Error: unexpected ‘)’ in “some.object <- 2)”

Explanation: There is a parenthesis somewhere that is not matching. In the example above there is an extra closing parenthesis after the 2 without a sister open parenthesis.

> some.object <- 2 # now this will work

Error in obj1 + obj2 : non-numeric argument to binary operator

Explanation: Mathematical operations in R only work with numbers, is one of obj1 or obj2 a character?

> obj1 <- 3
> obj2 <- "hi"
> obj1 + obj2 # bug!
> obj2 <- "3" # watch out, 3 is between quotation marks so interpreted as a character
> obj1 + obj2 # bug!
> obj2 <- 3
> obj1 + obj2 # no bug since both obj1 and obj2 are numbers now

Error: object ‘yourvar’ not found

Explanation: The object ‘yourvar’ is not in the R environment. Did you assign it a value?

> ls() # to view the objects currently in the R environment

> yourvar <- 2 # assign the value 2 to yourvar
> yourvar # now print it

## [1] 2

> yourvar * 2 # success

## [1] 4

If it is the column of a dataframe, make sure you specify that with mytunadf$yourvar.

Error in file(file, “rt”) : cannot open the connection In addition: Warning message: In file(file, “rt”) : cannot open file ‘file.txt’: No such file or directory

Explanation: the file ‘file.txt’ is not in your current working directory.

> # To see the current location of the working directory
> getwd()
> # To change the location of your working directory
> setwd("/my/new/working/directory") # specify path here, e.g. "C:/Projects/OFP-data" (note the "")
> # To see what files are in your current working directory
> list.files() # is file.txt here?