So, in this case, we may use R’s Switch statements, which have several benefits. A switch statement can be used to evaluate expressions using a String object, a List item, or a single integer; in other words, switch statements are suitable for fixed data values. For multi-way branching, Switch Statements are preferable. When we utilize switch statements (which is obvious when there is a great number), code processing is quick; when there are a huge number of cases, if-else statements take a long time. When we need to combine cases, switch statements are far less prone to errors because they are considerably cleaner.”
What are Strings in the R Programming Language in Ubuntu 20.04?
Long if expressions that test a variable to numerous integral values can be replaced with switch-cases, a multiway branch expression in R is called a switch case. The mapping and searching through a list of values technique is used in the Switch statement. If more than one value matches the expression, the switch statement returns the first value that matches the expression. One of the scenarios can be chosen in one of two ways: by index or by matching value.
Switch based on Index: When the cases are just numbers, and a statement is also an integer, the value of the statement is used to choose the case.
Switch based on Matching Value: Cases with both a case value and an output value, such as case 1=value1, are matched against the expression value. The output is the corresponding value when a match with a case is found.
Syntax of the Switch Case in the R Programming Language in Ubuntu 20.04
The Switch statement, which chooses one of the cases depending on the index, has the following syntax.
switch (expression, List_Cases)
The expression argument is analyzed here, and the relevant element in the collection is returned as a result of this value. The switch() method contains the first matched item if the value calculated from the expression satisfies more than one element.
Important Features of the Switch Case in R in Ubuntu 20.04?
- A character string that is always compared to the cases in the list.
- If an expression is not a string of characters, it is converted to an integer.
- The first match item will be used if there are several matches.
- If no matching case exists, an unrecognized case can be utilized.
How to Evaluate the Standard Error in the R in Ubuntu 20.04?
The basic ideas for constructing string vectors and character strings in R are covered in this chapter. You’ll also discover how R handles objects with characters in them.
Example # 1
Switch() returns the value depending on the element’s name if the given expression is a string of characters.
As we have a character “A” inside the defined variable “X.” So we are going to pass this variable inside our switch function. The switch function takes this X as an argument, and we have also defined the set of the cases inside it. The switch function returned the value of an element based on its name.
The unnamed element is returned if there is no match (if there is one). An error is thrown if there are several nameless elements. As there is no character, “D” is found in the list of values, and the last value in the list has no assigned character. So, if there is no match, the switch function just selects the unidentified element.
Example # 2
The expression and list arguments are the key arguments for the switch() function. Let’s discuss this statement with the example code.
Here, we have established a variable as Names and assigned the switch function to it. The switch function takes the integer value 2 as the first argument and the collection of names that represent the cases in the switch function. The switch expression is passed over each case for the matched name in the list. When the expression value is matched with the name, the switch operation is terminated. As the index value 2 has the name Alice so the name Alice is generated on the screen.
Example # 3
The switch() function can accept both integers and texts as cases. In this situation, it will carry out procedures on the variables first, and then, based on the output number, it will execute the case.
Example # 4
A string concatenation statement is used in the below R switch statement. Paste() function is a built-in R for joining vectors by transforming them into characters. The paste() method accepts three parameters and returns a string that has been concatenated. In R, the paste() function concatenates the vectors without using a separator. The paste() function joins vectors or strings together.
Here, we have created two variables, a and b, which are used inside the paste function. The switch function takes this paste function as the first argument, and the second argument is the element of the list. The paste function concatenates the variable’s values a and b and then matches the value inside the data list. As the concatenated value is 21 so the output value generated is “Good Night.”
Conclusion
In R, the switch() function uses the mapping strategy to search through a list of values. If there are several matches for a given value, the switch() method will produce the first match, which is the value that matches the expression. In comparison to the If-Else statement, switch cases are more efficient. With some examples, we have gone over the rules and several use cases for the switch Statements in R.
