In the previous tutorials, we learned about different types of data structures used in R such as vectors, lists, matrices, arrays, etc. Now it is time to understand how to identify through a column vector of data values to check whether it meets a certain condition or only executes a function if it meets a certain condition. So we need control structures or control statements that allow controlling the flow of a program.
In R programming language there are few control structures to control the flow of a program or to simply control flow statements. The most useful and simplest control flow statements in R are loops and decision-making statements.
In any programming language, the decision-making is implemented using some control structures or control flow statements. In simple terms, the control flow structures support to control of the flow of execution in R source code.
The program begins the execution sequentially from the first statement of the R source code. The control structures control the sequential flow with conditional statements like branching and iteration. Branching allows the currently executing piece of code(block) to jump to another part of the same program which results in a deviation from the default execution behavior.In this tutorial, we concentrate on learning the branching statements used to control the flow like If, if-else, nested else-if, switch, etc.
Control structures like for loop allow the simplification of code by avoiding repeated execution of the same code multiple times. It is often described by the term iteration. Iteration is a control structure that uses loops that allows to repeatedly execute a block (a piece of a program) of a statement till a condition applied is satisfying. In our next tutorial, we will discuss the for loop control structure in the R programming language.
The different types of control structures to control the flow of execution in the R programming language are given in the below table with a short description. In the coming sessions of this tutorial, you will learn in detail each control structure with examples. The picture depicts the available control structures in the R programming language.
The types of control structures can be grouped into three
|Types of control structures
|If and else
|To test whether a given condition is true or false
|To execute a loop when a condition is satisfied.
|To repeat the statement iteration
|To exit from a statement in iteration or loop
|To omit the current iteration and jumps to the next iteration cycle without terminating a loop.
|To return the result after execution
|To iterate over a statement (loop) multiple times.