Understand R Speak

R as a calculator

  • R can be used like a calculator type the following into your script.  To run it when your cursor is on the line in the script press Ctrl Enter
1 + 1
  • The console will give out the answer as 2.  The square brackets is the index number of the answer. In this case the answer is only one value
> 1 + 1
[1] 2
  • R follows the rules as any calculator.  In your script calculate the following
1+1
20*5
(45*3)+3.7
2^2
pi
(30/90)*100
  • The output will be as below
> 1+1
[1] 2
> 20*5
[1] 100
> (45*3)+3.7
[1] 138.7
> 2^2
[1] 4
> pi
[1] 3.141593
> (30/90)*100
[1] 33.33333

R functions

  • R is made up of thousands of functions that you use to manipulate and analyse your data.   They are the equivalent to maths functions in Excel e.g. STDEV(), SUM(), MEAN()

  • A collection of themed R functions for e.g. a data type, or an analysis type is called a package
  • R has thousands and thousands of packages to integrate with propriety software (ArcGIS, Stata), other tools (Twitter, SQL) and multiple data types (.txt, .csv, .sav) including compressed file formats (e.g. NetCDF)
  • Each function has a number of arguments that are conditions for how you apply or run the function.  All R functions follow the same format:

    Function_name(arg1, arg2, arg3...)

  • R has a wonderful help file to show you exactly how to use each function and argument....it even gives examples for you to work through. 


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