Switch Statement in R language is a control statement that is used to move the program control to one code line or module to another which is based upon the condition specified in the program. The switch statement is mostly used in the case of multiple condition check with a list of values scenarios in the R language.
Full Answer
How to create a switch statement in R?
The basic syntax for creating a switch statement in R is − switch (expression, case1, case2, case3....) The following rules apply to a switch statement − If the value of expression is not a character string it is coerced to integer.
How to check the levels of a factor in R?
Similarly, levels of a factor can be checked using the levels () function. How to create a factor in R? We can create a factor using the function factor (). Levels of a factor are inferred from the data if not provided.
What are levels in R with example?
For example: a data field such as marital status may contain only values from single, married, separated, divorced, or widowed. In such case, we know the possible values beforehand and these predefined, distinct values are called levels. Following is an example of factor in R. > x single married married single Levels: married single
What is switch in C++ with example?
switch (expression, list) Here, the expression is evaluated and based on this value, the corresponding item in the list is returned. If the value evaluated from the expression matches with more than one item of the list, switch () function returns the first matched item. Example: switch () function
How do I switch levels in R?
One way to change the level order is to use factor() on the factor and specify the order directly. In this example, the function ordered() could be used instead of factor() .
What does level () do in R?
Levels() function provides access to the levels attribute of a variable. The first form returns the value of the levels of its argument and the second sets the attribute.
How do you find the factor level in R?
We can check if a variable is a factor or not using class() function. Similarly, levels of a factor can be checked using the levels() function.
How do I check the level of data in R?
Get the Number of Levels of a Factor in R Programming – nlevels() Function.Convert a Data Frame into a Numeric Matrix in R Programming – data.matrix() Function.Shiny Package in R Programming.Data visualization with R and ggplot2.dplyr Package in R Programming.R Programming Language – Introduction.More items...•
What is R base package?
This package contains the basic functions which let R function as a language: arithmetic, input/output, basic programming support, etc. Its contents are available through inheritance from any environment. For a complete list of functions, use library(help = "base") .
What are levels in a Dataframe in R?
Most people get confused about levels and characters in R, especially the newbies. The difference is that levels specifically define the factor levels of a factor column and the characters are simple the character column that is not a factor or is not used as a factor but can be converted to a factor.
How many levels does factor R have?
four different factor levelsThe previous output of the RStudio console shows the structure of our example data: It's a factor vector consisting of eight vector elements. Note that our factor has four different factor levels – A, B, C, and D.
What does factor () do in R?
Factors in R are stored as a vector of integer values with a corresponding set of character values to use when the factor is displayed. The factor function is used to create a factor. The only required argument to factor is a vector of values which will be returned as a vector of factor values.
What does FCT mean in R?
factor variablefct: means a factor variable, also known as a categorical variable. int: means a quantitative variable that takes only integer or whole number values.
How do you find the level of a column in R?
To extract the factor levels from factor column, we can simply use levels function. For example, if we have a data frame called df that contains a factor column defined with x then the levels of factor levels in x can be extracted by using the command levels(df$x).
Which of the following is a base package for R language?
6. Which of the following is a base package for R language? Explanation: The other packages contained in the “base” system include utils, stats, datasets, graphics, grDevices, grid, methods, parallel, compiler, splines, tcltk, stats4.
What does stringsAsFactors mean in R?
The argument 'stringsAsFactors' is an argument to the 'data. frame()' function in R. It is a logical that indicates whether strings in a data frame should be treated as factor variables or as just plain strings. The argument also appears in 'read.
Description
switch evaluates EXPR and accordingly chooses one of the further arguments (in … ).
Value
The value of one of the elements of …, or NULL , invisibly (whenever no element is selected).
Warning
It is possible to write calls to switch that can be confusing and may not work in the same way in earlier versions of R. For compatibility (and clarity), always have EXPR as the first argument, naming it if partial matching is a possibility. For the character-string form, have a single unnamed argument as the default after the named values.
Details
switch works in two distinct ways depending whether the first argument evaluates to a character string or a number.
How to create a factor in R?
We can create a factor using the function factor (). Levels of a factor are inferred from the data if not provided.
How to access compoments of a factor?
Accessing components of a factor is very much similar to that of vectors.
How to modify a factor?
Components of a factor can be modified using simple assignments. However, we cannot choose values outside of its predefined levels.
Syntax of switch () function
Here, the expression is evaluated and based on this value, the corresponding item in the list is returned.
Example: switch () function
If the value evaluated is a number, that item of the list is returned.
Example: switch () Function with as String Expression
The expression used in the switch () function can be a string as well. In this case, the matching named item’s value is returned.
