How to write, save, and call your own functions in R With an Example

·         How to write?

                General form of function is

NameOfFun <- function(argument1,argument2...)

            {

                        Your expressions go here

            }

name <- function(x,y,..)

            {

                        if(.....) do something to x and or y

                        if(.....) do something to ............

            }

·         How to save?

                1- From R, write or paste your function code in R Editor or R script

                2- Save your function as "nameOfFile.R" in your working directory

                               

·         How to Call?

1-  in R Console type source("nameOfFile.R")

I have written a function that automatically assign letter grades. You can copy the function from

http://dl.dropbox.com/u/11248688/GradingFunction.txt

Or you can follow the following steps that may help you to know how to call a function:-

1- Download the function from

http://dl.dropbox.com/u/11248688/GradingFunction.zip

2- Unzip the folder and copy the file "GradingFunction.R" into your working Directory

3- Go to R, and type

source("GradingFunction.R") to call the function

4- If you are a TA and would like to try the function in your classes, follow the arguments of function as explained here

http://dl.dropbox.com/u/11248688/GradingFunction.txt

5- I have also randomly generated grades if you wish to try the function. There are two examples from the above link.

Note: This function may not directly related  to Data Analysis, but the process is the same (e.g., you want to assign labels into your grouping variables if conditions satisfied) 

Adil