Writing R programs

Although much data analysis in R can be carried out in an interactive manner using command prompt, often for more complex tasks, one needs to write R scripts. As mentioned in the introduction, R has both the perspective of a functional and object-oriented programming language. In this section, some of the standard syntaxes of the programming in R are described.

Control structures

Control structures are meant for controlling the flow of execution of a program. The standard control structures are as follows:

• if and else: To test a condition

• for: To loop over a set of statements for a fixed number of times

• while: To loop over a set of statements while a condition is true

• repeat: To execute an infinite loop

• break: To break the execution of a loop

• next: To skip an iteration of a loop

• return: To exit a function

Functions

If one wants to use R for more serious programming, it is essential to know how to write functions. They make the language more powerful and elegant. R has many...