Mod 2: Functions

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The provided dataset

assignment2 <- c(16, 18, 14, 22, 27, 17, 19, 17, 17, 22, 20, 22)

assignment2 <- c(16, 18, 14, 22, 27, 17, 19, 17, 17, 22, 20, 22)

The provided code

myMean <- function(assignment2) { return( sum(assignment) / length(someData) )}

myMean <- function(assignment2) { 
    
    # commented out due to error:
    # return(sum(assignment)/length(someData)) 
    
    # corrected version:
    return(sum(assignment2)/length(assignment2))
    
}
#tested <- myMean(assignment2)

Discussion

The code as provided will ultimately cause two errors:

• Error in myMean(assignment2) : object ‘assignment’ not found
• Error in myMean(assignment2) : object ‘someData’ not found
  

The code is intended to calculate the average of the dataset through a user-defined function. The two errors indicate that the function is attempting to access two unknown or undeclared variables: assignment and someData. Both unknowns should be replaced with the function’s receiving argument: assignment2.

So, corrected…the function now reads:

myMean <- function(assignment2) { return( sum(assignment2) / length(assignment2) )}

The call myMean(assignment2) will return myMean as: 19.25.

Sanity check, the built-in mean {base} function call of mean(assignment2) returns: 19.25.

Reference:

• Matloff, The Art of R Programming, section 1.3
  
  

GitHub

Related file(s) can be found at Git Me